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Bibliography on: Pangenome

The Electronic Scholarly Publishing Project: Providing world-wide, free access to classic scientific papers and other scholarly materials, since 1993.


ESP: PubMed Auto Bibliography 12 Aug 2022 at 01:32 Created: 


Although the enforced stability of genomic content is ubiquitous among MCEs, the opposite is proving to be the case among prokaryotes, which exhibit remarkable and adaptive plasticity of genomic content. Early bacterial whole-genome sequencing efforts discovered that whenever a particular "species" was re-sequenced, new genes were found that had not been detected earlier — entirely new genes, not merely new alleles. This led to the concepts of the bacterial core-genome, the set of genes found in all members of a particular "species", and the flex-genome, the set of genes found in some, but not all members of the "species". Together these make up the species' pan-genome.

Created with PubMed® Query: pangenome or "pan-genome" or "pan genome" NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)


RevDate: 2022-08-09

Xia F, Jiang M, Wen Z, et al (2022)

Complete Genomic Analysis of ST117 Lineage Extraintestinal Pathogenic Escherichia coli (ExPEC) to Reveal Multiple Genetic Determinants to Drive its Global Transmission: ST117 E. coli as An Emerging Multidrug-resistant Foodborne ExPEC with Zoonotic Potential.

Transboundary and emerging diseases [Epub ahead of print].

Avian pathogenic Escherichia coli (APEC) is recognized as a primary source of food-borne extraintestinal pathogenic E. coli (ExPEC), which poses a significant risk of extraintestinal infections in humans. The potential of human infection with ST117 lineage APEC/ExPEC from poultry is particularly concerning. However, relatively few whole-genome studies have focused on ST117 as an emerging ExPEC lineage. In this study, the complete genomes of 11 avian ST117 isolates and the draft genomes of 20 ST117 isolates in China were sequenced to reveal the genomic islands and large plasmid composition of ST117 APEC. With reference to the extensive E. coli genomes available in public databases, large-scale comprehensive genomic analysis of the ST117 lineage APEC/ExPEC was performed to reveal the features of the ST117 pan-genome and population. The high variability of the accessory genome emphasized the diversity and dynamic traits of the ST117 pan-genome. ST117 isolates recovered from different hosts and geographic sources were randomly located on a phylogeny tree, suggesting that ST117 E. coli lacked host specificity. A time-scaled phylogeny tree showed that ST117 was a recent E. coli lineage with a relatively short evolutionary period. Further characterization of a wide diversity of ExPEC-related virulence genes, PAIs, and resistance genes of the ST117 pan-genome provided insights into the virulence and resistance of ST117 APEC/ExPEC. The results suggested zoonotic potential of ST117 APEC/ExPEC between birds and humans. Moreover, genomic analysis showed that a pool of diverse plasmids drove the virulence and multidrug resistance of ST117 APEC/ExPEC. Several types of large plasmids were scattered across the ST117 isolates, but there was no strong plasmid-clade adaptation. Combined with the pan-genome analysis, a double polymerase chain reaction (PCR) method was designed for rapid and cost-effective detection of ST117 isolates from various of avian and human APEC/ExPEC isolates. Overall, this study addressed a gap in current knowledge about the ST117 APEC/ExPEC genome, with significant implications to understand the success and spread of ST117 APEC/ExPEC. This article is protected by copyright. All rights reserved.

RevDate: 2022-08-09

Goldman AD, B Kaçar (2022)

Very early evolution from the perspective of microbial ecology.

The universal ancestor at the root of the species tree of life depicts a population of organisms with a surprising degree of complexity, posessing genomes and translation systems much like that of microbial life today. As the first life forms were most likely to have been simple replicators, considerable evolutionary change must have taken place prior to the last universal common ancestor. It is often assumed that the lack of earlier branches on the tree of life is due to a prevalence of random horizontal gene transfer that obscured the delineations between lineages and hindered their divergence. Therefore, principles of microbial evolution and ecology may give us some insight into these early stages in the history of life. Here, we synthesize the current understanding of organismal and genome evolution from the perspective of microbial ecology and apply these evolutionary principles to the earliest stages of life on Earth. We focus especially on broad evolutionary modes pertaining to horizontal gene transfer, pangenome structure, and microbial mat communities.

RevDate: 2022-08-08

Camargo A, Guerrero-Araya E, Castañeda S, et al (2022)

Intra-species diversity of Clostridium perfringens: A diverse genetic repertoire reveals its pathogenic potential.

Frontiers in microbiology, 13:952081.

Clostridium perfringens is the causative agent of many enterotoxic diseases in humans and animals, and it is present in diverse environments (soil, food, sewage, and water). Multilocus Sequence Typing (MLST) and Whole Genome Sequencing (WGS) have provided a general approach about genetic diversity of C. perfringens; however, those studies are limited to specific locations and often include a reduced number of genomes. In this study, 372 C. perfringens genomes from multiple locations and sources were used to assess the genetic diversity and phylogenetic relatedness of this pathogen. In silico MLST was used for typing the isolates, and the resulting sequence types (ST) were assigned to clonal complexes (CC) based on allelic profiles that differ from its founder by up to double-locus variants. A pangenome analysis was conducted, and a core genome-based phylogenetic tree was created to define phylogenetic groups. Additionally, key virulence factors, toxinotypes, and antibiotic resistance genes were identified using ABRicate against Virulence Factor Database (VFDB), TOXiper, and Resfinder, respectively. The majority of the C. perfringens genomes found in publicly available databases were derived from food (n = 85) and bird (n = 85) isolates. A total of 195 STs, some of them shared between sources such as food and human, horses and dogs, and environment and birds, were grouped in 25 CC and distributed along five phylogenetic groups. Fifty-three percent of the genomes were allocated to toxinotype A, followed by F (32%) and G (7%). The most frequently found virulence factors based on > 70% coverage and 99.95% identity were plc (100%), nanH (99%), ccp (99%), and colA (98%), which encode an alpha-toxin, a sialidase, an alpha-clostripain, and a collagenase, respectively, while tetA (39.5%) and tetB (36.2%), which mediate tetracycline resistance determinants, were the most common antibiotic resistance genes detected. The analyses conducted here showed a better view of the presence of this pathogen across several host species. They also confirm that the genetic diversity of C. perfringens is based on a large number of virulence factors that vary among phylogroups, and antibiotic resistance markers, especially to tetracyclines, aminoglycosides, and macrolides. Those characteristics highlight the importance of C. perfringens as a one of the most common causes of foodborne illness.

RevDate: 2022-08-04

Meleshko D, Yang R, Marks P, et al (2022)

Efficient detection and assembly of non-reference DNA sequences with synthetic long reads.

Nucleic acids research pii:6655589 [Epub ahead of print].

Recent pan-genome studies have revealed an abundance of DNA sequences in human genomes that are not present in the reference genome. A lion's share of these non-reference sequences (NRSs) cannot be reliably assembled or placed on the reference genome. Improvements in long-read and synthetic long-read (aka linked-read) technologies have great potential for the characterization of NRSs. While synthetic long reads require less input DNA than long-read datasets, they are algorithmically more challenging to use. Except for computationally expensive whole-genome assembly methods, there is no synthetic long-read method for NRS detection. We propose a novel integrated alignment-based and local assembly-based algorithm, Novel-X, that uses the barcode information encoded in synthetic long reads to improve the detection of such events without a whole-genome de novo assembly. Our evaluations demonstrate that Novel-X finds many non-reference sequences that cannot be found by state-of-the-art short-read methods. We applied Novel-X to a diverse set of 68 samples from the Polaris HiSeq 4000 PGx cohort. Novel-X discovered 16 691 NRS insertions of size > 300 bp (total length 18.2 Mb). Many of them are population specific or may have a functional impact.

RevDate: 2022-08-02

Dereeper A, Summo M, DF Meyer (2022)

PanExplorer: A web-based tool for exploratory analysis and visualization of bacterial pan-genomes.

Bioinformatics (Oxford, England) pii:6653297 [Epub ahead of print].

MOTIVATION: As pan-genome approaches are largely employed for bacterial comparative genomics and evolution analyses, but still difficult to be carried out by non-bioinformatician biologists, there is a need for an innovative tool facilitating the exploration of bacterial pan-genomes.

RESULTS: PanExplorer is a web application providing various genomic analyses and reports, giving intuitive views that enable a better understanding of bacterial pan-genomes. As an example, we produced the pan-genome for 121 Anaplasmataceae strains (including 30 Ehrlichia, 15 Anaplasma, 68 Wolbachia).

PanExplorer is written in Perl CGI and relies on several JavaScript libraries for visualization (hotmap.js, MauveViewer, CircosJS). It is freely available at The source code has been released in a GitHub repository A documentation section is available on PanExplorer website.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2022-08-01

Zheng X, Dai X, Zhu Y, et al (2022)

(Meta)Genomic Analysis Reveals Diverse Energy Conservation Strategies Employed by Globally Distributed Gemmatimonadota.

mSystems [Epub ahead of print].

Gemmatimonadota is a phylum-level lineage distributed widely but rarely reported. Only six representatives of Gemmatimonadota have so far been isolated and cultured in laboratory. The physiology, ecology, and evolutionary history of this phylum remain unknown. The 16S rRNA gene survey of our salt lake and deep-sea sediments, and Earth Microbiome Project (EMP) samples, reveals that Gemmatimonadota exist in diverse environments globally. In this study, we retrieved 17 metagenome-assembled genomes (MAGs) from salt lake sediments (12 MAGs) and deep-sea sediments (5 MAGs). Analysis of these MAGs and the nonredundant MAGs or genomes from public databases reveals Gemmatimonadota can degrade various complex organic substrates, and mainly employ heterotrophic pathways (e.g., glycolysis and tricarboxylic acid [TCA] cycle) for growth via aerobic respiration. And the processes of sufficient energy being stored in glucose through gluconeogenesis, followed by the synthesis of more complex compounds, are prevalent in Gemmatimonadota. A highly expandable pangenome for Gemmatimonadota has been observed, which presumably results from their adaptation to thriving in diverse environments. The enrichment of the Na+/H+ antiporter in the SG8-23 order represents their adaptation to salty habitats. Notably, we identified a novel lineage of the SG8-23 order, which is potentially anoxygenic phototrophic. This lineage is not closely related to the phototrophs in the order of Gemmatimonadales. The two orders differ distinctly in the gene organization and phylogenetic relationship of their photosynthesis gene clusters, indicating photosystems in Gemmatimonadota have evolved in two independent routes. IMPORTANCE The phylum Gemmatimonadota is widely distributed in various environments. However, their physiology, ecology and evolutionary history remain unknown, primary due to the limited cultured isolates and available genomes. We were intrigued to find out how widespread this phylum is, and how it can thrive under diverse conditions. Our results here expand the knowledge of the genetic and metabolic diversity of Gemmatimonadota, and shed light on the diverse energy conservation strategies (i.e., oxidative phosphorylation, substrate phosphorylation, and photosynthetic phosphorylation) responsible for their global distribution. Moreover, gene organization and phylogenetic analysis of photosynthesis gene clusters in Gemmatimonadota provide a valuable insight into the evolutionary history of photosynthesis.

RevDate: 2022-08-02

Zhang Y, Chu H, Yu L, et al (2022)

Analysis of the Taxonomy, Synteny, and Virulence Factors for Soft Rot Pathogen Pectobacterium aroidearum in Amorphophallus konjac Using Comparative Genomics.

Frontiers in microbiology, 13:868709.

Bacterial soft rot is a devastating disease for a wide range of crops, vegetables, and ornamental plants including konjac (Amorphophallus konjac). However, the pangenome and genomic plasticity of the konjac soft rot pathogens is little explored. In this study, we reported the complete genome sequences of 11 bacterial isolates that can cause typical soft rot symptoms in konjac by in vitro and in vivo pathogenicity tests. Based on in silico DNA-DNA hybridization, average nucleotide identity and phylogenomic analysis, all 11 isolates were determined to be Pectobacterium aroidearum. In addition, synteny analysis of these genomes revealed considerable chromosomal inversions, one of which is triggered by homologous recombination of ribose operon. Pangenome analysis and COG enrichment analysis showed that the pangenome of P. aroidearum is open and that accessory genes are enriched in replication, recombination, and repair. Variations in type IV secretion system and type VI secretion system were found, while plant cell wall degrading enzymes were conserved. Furthermore, sequence analyses also provided evidence for the presence of a type V secretion system in Pectobacterium. These findings advance our understanding of the pathogenicity determinants, genomic plasticity, and evolution of P. aroidearum.

RevDate: 2022-08-02

Wu J, Xu XD, Liu L, et al (2022)

A Chromosome Level Genome Assembly of a Winter Turnip Rape (Brassica rapa L.) to Explore the Genetic Basis of Cold Tolerance.

Frontiers in plant science, 13:936958.

Winter rapeseed (Brassica rapa L.) is an important overwintering oilseed crop that is widely planted in northwest China and suffers chronic low temperatures in winter. So the cold stress becomes one of the major constraints that limit its production. The currently existing genomes limit the understanding of the cold-tolerant genetic basis of rapeseed. Here we assembled a high-quality long-read genome of B. rapa "Longyou-7" cultivar, which has a cold-tolerant phenotype, and constructed a graph-based pan-genome to detect the structural variations within homologs of currently reported cold-tolerant related genes in the "Longyou-7" genome, which provides an additional elucidation of the cold-tolerant genetic basis of "Longyou-7" cultivar and promotes the development of cold-tolerant breeding in B. rapa.

RevDate: 2022-08-03
CmpDate: 2022-08-02

Aurongzeb M, Rashid Y, Habib Ahmed Naqvi S, et al (2022)

Insights into genome evolution, pan-genome, and phylogenetic implication through mitochondrial genome sequence of Naegleria fowleri species.

Scientific reports, 12(1):13152.

In the current study, we have systematically analysed the mitochondrial DNA (mtDNA) sequence of Naegleria fowleri (N. fowleri) isolate AY27, isolated from Karachi, Pakistan. The N. fowleri isolate AY27 has a circular mtDNA (49,541 bp), which harbours 69 genes (46 protein-coding genes, 21 tRNAs and 2 rRNAs). The pan-genome analysis of N. fowleri species showed a Bpan value of 0.137048, which implies that the pan-genome is open. KEGG classified core, accessory and unique gene clusters for human disease, metabolism, environmental information processing, genetic information processing and organismal system. Similarly, COG characterization of protein showed that core and accessory genes are involved in metabolism, information storages and processing, and cellular processes and signaling. The Naegleria species (n = 6) formed a total of 47 gene clusters; 42 single-copy gene clusters and 5 orthologous gene clusters. It was noted that 100% genes of Naegleria species were present in the orthogroups. We identified 44 single nucleotide polymorphisms (SNP) in the N. fowleri isolate AY27 mtDNA using N. fowleri strain V511 as a reference. Whole mtDNA phylogenetic tree analysis showed that N. fowleri isolates AY27 is closely related to N. fowleri (Accession no. JX174181.1). The ANI (Average Nucleotide Identity) values presented a much clear grouping of the Naegleria species compared to the whole mtDNA based phylogenetic analysis. The current study gives a comprehensive understanding of mtDNA architecture as well as a comparison of Naegleria species (N. fowleri and N. gruberi species) at the mitochondrial genome sequence level.

RevDate: 2022-07-28

Singh PK, Rawal HC, Panda AK, et al (2022)

Pan-genomic, transcriptomic, and miRNA analyses to decipher genetic diversity and anthocyanin pathway genes among the traditional rice landraces.

Genomics pii:S0888-7543(22)00181-1 [Epub ahead of print].

Black rice is famous for containing high anthocyanin while Joha rice is aromatic with low anthocyanin containing rice from the North Eastern Region (NER) of India. However, there are limited reports on the anthocyanin biosynthesis in Manipur Black rice. Therefore, the present study was aimed to understand the origin, domestication and anthocyanin biosynthesis pathways in Black rice using the next generation sequencing of approaches. With the sequencing data, various analyses were carried out for differential expression and construction of a pan-genome. Protein coding RNA and small RNA sequencing analysis aided in determining 7415 and 131 differentially expressed transcripts and miRNAs, respectively in NER rice. This is the first extensive study on identification and expression analysis of miRNAs and their target genes in regulating anthocyanin biosynthesis in NER rice. This study will aid in better understanding for decoding the theory of high or low anthocyanin content in different rice genotypes.

RevDate: 2022-07-31

Alshabrmi FM, Alrumaihi F, Alrasheedi SF, et al (2022)

An In-Silico Investigation to Design a Multi-Epitopes Vaccine against Multi-Drug Resistant Hafnia alvei.

Vaccines, 10(7):.

Antimicrobial resistance has become a significant health issue because of the misuse of antibiotics in our daily lives, resulting in high rates of morbidity and mortality. Hafnia alvei is a rod-shaped, Gram-negative and facultative anaerobic bacteria. The medical community has emphasized H. alvei's possible association with gastroenteritis. As of now, there is no licensed vaccine for H. alvei, and as such, computer aided vaccine design approaches could be an ideal approach to highlight the potential vaccine epitopes against this bacteria. By using bacterial pan-genome analysis (BPGA), we were able to study the entire proteomes of H. alvei with the aim of developing a vaccine. Based on the analysis, 20,370 proteins were identified as core proteins, which were further used in identifying potential vaccine targets based on several vaccine candidacy parameters. The prioritized vaccine targets against the bacteria are; type 1 fimbrial protein, flagellar hook length control protein (FliK), flagellar hook associated protein (FlgK), curli production assembly/transport protein (CsgF), fimbria/pilus outer membrane usher protein, fimbria/pilus outer membrane usher protein, molecular chaperone, flagellar filament capping protein (FliD), TonB-dependent hemoglobin /transferrin/lactoferrin family receptor, Porin (OmpA), flagellar basal body rod protein (FlgF) and flagellar hook-basal body complex protein (FliE). During the epitope prediction phase, different antigenic, immunogenic, non-Allergenic, and non-Toxic epitopes were predicted for the above-mentioned proteins. The selected epitopes were combined to generate a multi-epitope vaccine construct and a cholera toxin B subunit (adjuvant) was added to enhance the vaccine's antigenicity. Downward analyses of vaccines were performed using a vaccine three-dimensional model. Docking studies have confirmed that the vaccine strongly binds with MHC-I, MHC-II, and TLR-4 immune cell receptors. Additionally, molecular dynamics simulations confirmed that the vaccine epitopes were exposed to nature and to the host immune system and interpreted strong intermolecular binding between the vaccine and receptors. Based on the results of the study, the model vaccine construct seems to have the capacity to produce protective immune responses in the host, making it an attractive candidate for further in vitro and in vivo studies.

RevDate: 2022-07-31

Bukhari SAR, Irfan M, Ahmad I, et al (2022)

Comparative Genomics and Pan-Genome Driven Prediction of a Reduced Genome of Akkermansia muciniphila.

Microorganisms, 10(7):.

Akkermanisia muciniphila imparts important health benefits and is considered a next-generation probiotic. It is imperative to understand the genomic diversity and metabolic potential of the species for safer applications as probiotics. As it resides with both health-promoting and pathogenic bacteria, understanding the evolutionary patterns are crucial, but this area remains largely unexplored. Moreover, pan-genome has previously been established based on only a limited number of strains and without careful strain selection. The pan-genomics have become very important for understanding species diversity and evolution. In the current study, a systematic approach was used to find a refined pan-genome profile of A. muciniphila by excluding too-diverse strains based on average nucleotide identity-based species demarcation. The strains were divided into four phylogroups using a variety of clustering techniques. Horizontal gene transfer and recombination patterns were also elucidated. Evolutionary patterns revealed that different phylogroups were expanding differently. Furthermore, a comparative evaluation of the metabolic potential of the pan-genome and its subsections was performed. Lastly, the study combines functional annotation, persistent genome, and essential genes to devise an approach to determine a minimal genome that can systematically remove unwanted genes, including virulent factors. The selection of one strain to be used as a chassis for the prediction of a reduced genome was very carefully performed by analyzing several genomic parameters, including the number of unique genes and the resistance and pathogenic potential of the strains. The strategy could be applied to other microbes, including human-associated microbiota, towards a common goal of predicting a minimal or a reduced genome.

RevDate: 2022-07-31

Maphosa MN, Steenkamp ET, Kanzi AM, et al (2022)

Intra-Species Genomic Variation in the Pine Pathogen Fusarium circinatum.

Journal of fungi (Basel, Switzerland), 8(7):.

Fusarium circinatum is an important global pathogen of pine trees. Genome plasticity has been observed in different isolates of the fungus, but no genome comparisons are available. To address this gap, we sequenced and assembled to chromosome level five isolates of F. circinatum. These genomes were analysed together with previously published genomes of F. circinatum isolates, FSP34 and KS17. Multi-sample variant calling identified a total of 461,683 micro variants (SNPs and small indels) and a total of 1828 macro structural variants of which 1717 were copy number variants and 111 were inversions. The variant density was higher on the sub-telomeric regions of chromosomes. Variant annotation revealed that genes involved in transcription, transport, metabolism and transmembrane proteins were overrepresented in gene sets that were affected by high impact variants. A core genome representing genomic elements that were conserved in all the isolates and a non-redundant pangenome representing all genomic elements is presented. Whole genome alignments showed that an average of 93% of the genomic elements were present in all isolates. The results of this study reveal that some genomic elements are not conserved within the isolates and some variants are high impact. The described genome-scale variations will help to inform novel disease management strategies against the pathogen.

RevDate: 2022-07-31
CmpDate: 2022-07-28

Li G, Shu J, Jin J, et al (2022)

Development of a Multi-Epitope Vaccine for Mycoplasma hyopneumoniae and Evaluation of Its Immune Responses in Mice and Piglets.

International journal of molecular sciences, 23(14):.

Mycoplasma hyopneumoniae (Mhp), the primary pathogen causing Mycoplasma pneumonia of swine (MPS), brings massive economic losses worldwide. Genomic variability and post-translational protein modification can enhance the immune evasion of Mhp, which makes MPS prone to recurrent outbreaks on farms, even with vaccination or other treatments. The reverse vaccinology pipeline has been developed as an attractive potential method for vaccine development due to its high efficiency and applicability. In this study, a multi-epitope vaccine for Mhp was developed, and its immune responses were evaluated in mice and piglets. Genomic core proteins of Mhp were retrieved through pan-genome analysis, and four immunodominant antigens were screened by host homologous protein removal, membrane protein screening, and virulence factor identification. One immunodominant antigen, AAV27984.1 (membrane nuclease), was expressed by E. coli and named rMhp597. For epitope prioritization, 35 B-cell-derived epitopes were identified from the four immunodominant antigens, and 10 MHC-I and 6 MHC-II binding epitopes were further identified. The MHC-I/II binding epitopes were merged and combined to produce recombinant proteins MhpMEV and MhpMEVC6His, which were used for animal immunization and structural analysis, respectively. Immunization of mice and piglets demonstrated that MhpMEV could induce humoral and cellular immune responses. The mouse serum antibodies could detect all 11 synthetic epitopes, and the piglet antiserum suppressed the nuclease activity of rMhp597. Moreover, piglet serum antibodies could also detect cultured Mhp strain 168. In summary, this study provides immunoassay results for a multi-epitope vaccine derived from the reverse vaccinology pipeline, and offers an alternative vaccine for MPS.

RevDate: 2022-07-31
CmpDate: 2022-07-28

Rida T, Ahmad S, Ullah A, et al (2022)

Pan-Genome Analysis of Oral Bacterial Pathogens to Predict a Potential Novel Multi-Epitopes Vaccine Candidate.

International journal of environmental research and public health, 19(14):.

Porphyromonas gingivalis is a Gram-negative anaerobic bacterium, mainly present in the oral cavity and causes periodontal infections. Currently, no licensed vaccine is available against P. gingivalis and other oral bacterial pathogens. To develop a vaccine against P. gingivalis, herein, we applied a bacterial pan-genome analysis (BPGA) on the bacterial genomes that retrieved a total number of 4908 core proteins, which were further utilized for the identification of good vaccine candidates. After several vaccine candidacy analyses, three proteins, namely lytic transglycosylase domain-containing protein, FKBP-type peptidyl-propyl cis-trans isomerase and superoxide dismutase, were shortlisted for epitopes prediction. In the epitopes prediction phase, different types of B and T-cell epitopes were predicted and only those with an antigenic, immunogenic, non-allergenic, and non-toxic profile were selected. Moreover, all the predicted epitopes were joined with each other to make a multi-epitopes vaccine construct, which was linked further to the cholera toxin B-subunit to enhance the antigenicity of the vaccine. For downward analysis, a three dimensional structure of the designed vaccine was modeled. The modeled structure was checked for binding potency with major histocompatibility complex I (MHC-I), major histocompatibility complex II (MHC-II), and Toll-like receptor 4 (TLR-4) immune cell receptors which revealed that the designed vaccine performed proper binding with respect to immune cell receptors. Additionally, the binding efficacy of the vaccine was validated through a molecular dynamic simulation that interpreted strong intermolecular vaccine-receptor binding and confirmed the exposed situation of vaccine epitopes to the host immune system. In conclusion, the study suggested that the model vaccine construct has the potency to generate protective host immune responses and that it might be a good vaccine candidate for experimental in vivo and in vitro studies.

RevDate: 2022-07-31

Ezzeroug Ezzraimi A, Hannachi N, Mariotti A, et al (2022)

The Antibacterial Effect of Platelets on Escherichia coli Strains.

Biomedicines, 10(7):.

Platelets play an important role in defense against pathogens; however, the interaction between Escherichia coli and platelets has not been well described and detailed. Our goal was to study the interaction between platelets and selected strains of E. coli in order to evaluate the antibacterial effect of platelets and to assess bacterial effects on platelet activation. Washed platelets and supernatants of pre-activated platelets were incubated with five clinical colistin-resistant and five laboratory colistin-sensitive strains of E. coli in order to study bacterial growth. Platelet activation was measured with flow cytometry by evaluating CD62P expression. To identify the difference in strain behavior toward platelets, a pangenome analysis using Roary and O-antigen serotyping was carried out. Both whole platelets and the supernatant of activated platelets inhibited growth of three laboratory colistin-sensitive strains. In contrast, platelets promoted growth of the other strains. There was a negative correlation between platelet activation and bacterial growth. The Roary results showed no logical clustering to explain the mechanism of platelet resistance. The diversity of the responses might be due to strains of different types of O-antigen. Our results show a bidirectional interaction between platelets and E. coli whose expression is dependent on the bacterial strain involved.

RevDate: 2022-07-25

Suraby EJ, Sruthi KB, G Antony (2022)

Genome-wide identification of type III effectors and other virulence factors in Ralstonia pseudosolanacearum causing bacterial wilt in ginger (Zingiber officinale).

Molecular genetics and genomics : MGG [Epub ahead of print].

Ralstonia pseudosolanacearum causes bacterial wilt in ginger, reducing ginger production worldwide. We sequenced the whole genome of a highly virulent phylotype I, race 4, biovar 3 Ralstonia pseudosolanacearum strain GRsMep isolated from a severely infected ginger field in India. R. pseudosolanacearum GRsMep genome is organised into two replicons: chromosome and megaplasmid with a total genome size of 5,810,605 bp. This strain encodes approximately 72 effectors which include a combination of core effectors as well as highly variable, diverse repertoire of type III effectors. Comparative genome analysis with GMI1000 identified conservation in the genes involved in the general virulence mechanism. Our analysis identified type III effectors, RipBJ and RipBO as present in GRsMep but absent in the reported genomes of other strains infecting Zingiberaceae family. GRsMep contains 126 unique genes when compared to the pangenome of the Ralstonia strains that infect the Zingiberaceae family. The whole-genome data of R. pseudosolanacearum strain will serve as a resource for exploring the evolutionary processes that structure and regulate the virulence determinants of the strain. Pathogenicity testing of the transposon insertional mutant library of GRsMep through virulence assay on ginger plants identified a few candidate virulence determinants specific to bacterial wilt in ginger.

RevDate: 2022-07-25

Dang VH, Hill CB, Zhang XQ, et al (2022)

Multi-locus genome-wide association studies reveal novel alleles for flowering time under vernalisation and extended photoperiod in a barley MAGIC population.

TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik [Epub ahead of print].

KEY MESSAGE: Key genes controlling flowering and interactions of different photoperiod alleles with various environments were identified in a barley MAGIC population. A new candidate gene for vernalisation requirements was also detected. Optimal flowering time has a major impact on grain yield in crop species, including the globally important temperate cereal crop barley (Hordeum vulgare L.). Understanding the genetics of flowering is a key avenue to enhancing yield potential. Although bi-parental populations were used intensively to map genes controlling flowering, their lack of genetic diversity requires additional work to obtain desired gene combinations in the selected lines, especially when the two parental cultivars did not carry the genes. Multi-parent mapping populations, which use a combination of four or eight parental cultivars, have higher genetic and phenotypic diversity and can provide novel genetic combinations that cannot be achieved using bi-parental populations. This study uses a Multi-parent advanced generation intercross (MAGIC) population from four commercial barley cultivars to identify genes controlling flowering time in different environmental conditions. Genome-wide association studies (GWAS) were performed using 5,112 high-quality markers from Diversity Arrays Technology sequencing (DArT-seq), and Kompetitive allele-specific polymerase chain reaction (KASP) genetic markers were developed. Phenotypic data were collected from fifteen different field trials for three consecutive years. Planting was conducted at various sowing times, and plants were grown with/without additional vernalisation and extended photoperiod treatments. This study detected fourteen stable regions associated with flowering time across multiple environments. GWAS combined with pangenome data highlighted the role of CEN gene in flowering and enabled the prediction of different CEN alleles from parental lines. As the founder lines of the multi-parental population are elite germplasm, the favourable alleles identified in this study are directly relevant to breeding, increasing the efficiency of subsequent breeding strategies and offering better grain yield and adaptation to growing conditions.

RevDate: 2022-07-26

Wang Z, Yang J, Cheng F, et al (2022)

Subgenome dominance and its evolutionary implications in crop domestication and breeding.

Horticulture research, 9:uhac090.

Polyploidization or whole-genome duplication (WGD) is a well-known speciation and adaptation mechanism in angiosperms, while subgenome dominance is a crucial phenomenon in allopolyploids, established following polyploidization. The dominant subgenomes contribute more to genome evolution and homoeolog expression bias, both of which confer advantages for short-term phenotypic adaptation and long-term domestication. In this review, we firstly summarize the probable mechanistic basis for subgenome dominance, including the effects of genetic [transposon, genetic incompatibility, and homoeologous exchange (HE)], epigenetic (DNA methylation and histone modification), and developmental and environmental factors on this evolutionary process. We then move to Brassica rapa, a typical allopolyploid with subgenome dominance. Polyploidization provides the B. rapa genome not only with the genomic plasticity for adapting to changeable environments, but also an abundant genetic basis for morphological variation, making it a representative species for subgenome dominance studies. According to the 'two-step theory', B. rapa experienced genome fractionation twice during WGD, in which most of the genes responding to the environmental cues and phytohormones were over-retained, enhancing subgenome dominance and consequent adaption. More than this, the pangenome of 18 B. rapa accessions with different morphotypes recently constructed provides further evidence to reveal the impacts of polyploidization and subgenome dominance on intraspecific diversification in B. rapa. Above and beyond the fundamental understanding of WGD and subgenome dominance in B. rapa and other plants, however, it remains elusive why subgenome dominance has tissue- and spatiotemporal-specific features and could shuffle between homoeologous regions of different subgenomes by environments in allopolyploids. We lastly propose acceleration of the combined application of resynthesized allopolyploids, omics technology, and genome editing tools to deepen mechanistic investigations of subgenome dominance, both genetic and epigenetic, in a variety of species and environments. We believe that the implications of genomic and genetic basis of a variety of ecologically, evolutionarily, and agriculturally interesting traits coupled with subgenome dominance will be uncovered and aid in making new discoveries and crop breeding.

RevDate: 2022-07-26
CmpDate: 2022-07-26

Kopf A, Bunk B, Coldewey SM, et al (2022)

Comparative Genomic Analysis of the Human Pathogen Wohlfahrtiimonas Chitiniclastica Provides Insight Into the Identification of Antimicrobial Resistance Genotypes and Potential Virulence Traits.

Frontiers in cellular and infection microbiology, 12:912427.

Recent studies suggest that Wohlfahrtiimonas chitiniclastica may be the cause of several diseases in humans including sepsis and bacteremia making the bacterium as a previously underappreciated human pathogen. However, very little is known about the pathogenicity and genetic potential of W. chitiniclastica; therefore, it is necessary to conduct systematic studies to gain a deeper understanding of its virulence characteristics and treatment options. In this study, the entire genetic repertoire of all publicly available W. chitiniclastica genomes was examined including in silico characterization of bacteriophage content, antibiotic resistome, and putative virulence profile. The pan-genome of W. chitiniclastica comprises 3819 genes with 1622 core genes (43%) indicating a putative metabolic conserved species. Furthermore, in silico analysis indicated presumed resistome expansion as defined by the presence of genome-encoded transposons and bacteriophages. While macrolide resistance genes macA and macB are located within the core genome, additional antimicrobial resistance genotypes for tetracycline (tetH, tetB, and tetD), aminoglycosides (ant(2'')-Ia, aac(6')-Ia,aph(3'')-Ib, aph(3')-Ia, and aph(6)-Id)), sulfonamide (sul2), streptomycin (strA), chloramphenicol (cat3), and beta-lactamase (blaVEB) are distributed among the accessory genome. Notably, our data indicate that the type strain DSM 18708T does not encode any additional clinically relevant antibiotic resistance genes, whereas drug resistance is increasing within the W. chitiniclastica clade. This trend should be monitored with caution. To the best of our knowledge, this is the first comprehensive genome analysis of this species, providing new insights into the genome of this opportunistic human pathogen.

RevDate: 2022-07-23

Li Y, Wang Y, J Liu (2022)

Genomic Insights Into the Interspecific Diversity and Evolution of Mobiluncus, a Pathogen Associated With Bacterial Vaginosis.

Frontiers in microbiology, 13:939406.

Bacterial vaginosis (BV) is a common vaginal infection and has been associated with increased risk for a wide array of health issues. BV is linked with a variety of heterogeneous pathogenic anaerobic bacteria, among which Mobiluncus is strongly associated with BV diagnosis. However, their genetic features, pathogenicity, interspecific diversity, and evolutionary characters have not been illustrated at genomic level. The current study performed phylogenomic and comparative genomic analyses of Mobiluncus. Phylogenomic analyses revealed remarkable phylogenetic distinctions among different species. Compared with M. curtisii, M. mulieris had a larger genome and pangenome size with more insertion sequences but less CRISPR-Cas systems. In addition, these two species were diverse in profile of virulence factors, but harbored similar antibiotic resistance genes. Statistically different functional genome profiles between strains from the two species were determined, as well as correlations of some functional genes/pathways with putative pathogenicity. We also showed that high levels of horizontal gene transfer might be an important strategy for species diversification and pathogenicity. Collectively, this study provides the first genome sequence level description of Mobiluncus, and may shed light on its virulence/pathogenicity, functional diversification, and evolutionary dynamics. Our study could facilitate the further investigations of this important pathogen, and might improve the future treatment of BV.

RevDate: 2022-08-03

Dindhoria K, Kumar S, Baliyan N, et al (2022)

Bacillus licheniformis MCC 2514 genome sequencing and functional annotation for providing genetic evidence for probiotic gut adhesion properties and its applicability as a bio-preservative agent.

Gene, 840:146744 pii:S0378-1119(22)00563-7 [Epub ahead of print].

Bacillus licheniformis is a well-known probiotic that can be found in a variety of foods. The strain Bacillus licheniformis MCC 2514 was previously characterized by our group for its bio-physiological capabilities establishing it as a promising probiotic, but information on the genetic evidence for its attributes was lacking. In the current study, whole genome analysis identified the underlying molecular determinants responsible for its probiotic potential. The circular genome of MCC 2514 was 4,230,480 bp with 46.2% GC content, 24 rRNA, and 83 tRNA genes. The pangenome analysis between B. licheniformis MCC 2514 and 12 other B. licheniformis strains revealed a pangenome of 6008 genes and core genome of 3775 genes. Genome mining revealed NRPS and bacteriocins producing gene clusters indicating its biocontrol properties. Several genes encoding carbohydrate degrading enzymes, which aid in proper food degradation in the intestine, were also observed. Stress tolerance, vitamin, and essential amino acids biosynthesis related genes were found, which are important characteristics of a probiotic strain. Additionally, vital genes responsible for gut adhesion and biofilm formation were observed in its genome. The bacterium has been shown to improve the shelf life of idli batter by preventing whey separation, CO2, and odour production while maintaining the pH of 3.96-4.29, especially at cold temperatures. It has significantly reduced coliform contamination at both room and low temperatures, demonstrating its bio-preservative ability, which is also corroborated by the presence of the NRPS and bacteriocin gene clusters in its genome. The present study helped to understand both, the ability of B. licheniformis MCC 2514 to adapt the intestinal gut environment and its probiotic functionality for food preservation.

RevDate: 2022-07-21

Wang Z, Guo G, Li Q, et al (2022)

Combing Immunoinformatics with Pangenome Analysis To Design a Multiepitope Subunit Vaccine against Klebsiella pneumoniae K1, K2, K47, and K64.

Microbiology spectrum [Epub ahead of print].

Klebsiella pneumoniae is an opportunistic Gram-negative bacterium that has become a leading causative agent of nosocomial infections, mainly infecting patients with immunosuppressive diseases. Capsular (K) serotypes K1, K2, K47, and K64 are commonly associated with higher virulence (hypervirulent Klebsiella pneumoniae), and more threateningly, isolates belonging to the last two K serotypes are also frequently associated with resistance to carbapenem (hypervirulent carbapenem-resistant Klebsiella pneumoniae). The prevalence of these isolates has posed significant threats to human health, and there are no appropriate therapies available against them. Therefore, in this study, a method combining immunoinformatics and pangenome analysis was applied for contriving a multiepitope subunit vaccine against these four threatening serotypes. To obtain cross-protection, 12 predicted conserved antigens were screened from the core genome of 274 complete Klebsiella pneumoniae genomes (KL1, KL2, KL47, and KL64), from which the epitopes of T and B cells were extracted for vaccine construction. In addition, the immunological properties, the interaction with Toll-like receptors, and the stability in a simulative humoral environment were evaluated by immunoinformatics methods, molecular docking, and molecular dynamics simulation. All of these evaluations indicated the potency of this constructed vaccine to be an effective therapeutic agent. Lastly, the cDNA of the designed vaccine was optimized and ligated to pET-28a(+) for expression vector construction. Overall, our research provides a newly cross-protective control strategy against these troublesome pathogens and paves the way for the development of a safe and effective vaccine. IMPORTANCE Klebsiella pneumoniae is an opportunistic Gram-negative bacterium that has become a leading causative agent of nosocomial infections. Among the numerous capsular serotypes, K1, K2, K47, and K64 are commonly associated with higher virulence (hypervirulent K. pneumoniae). More threateningly, the last two serotypes are frequently associated with resistance to carbapenem (hypervirulent carbapenem-resistant K. pneumoniae). However, there is currently no therapeutic agent or vaccine specifically against these isolates. Therefore, development of a vaccine against these pathogens is very essential. In this study, for the first time, a method combining pangenome analysis, reverse vaccinology, and immunoinformatics was applied for contriving a multiepitope subunit vaccine against K. pneumoniae isolates of K1, K2, K47, and K64. Also, the immunological properties of the constructed vaccine were evaluated and its high potency was revealed. Overall, our research will pave the way for the vaccine development against these four threatening capsular serotypes of K. pneumoniae.

RevDate: 2022-07-21

Sassi M, Bronsard J, Pascreau G, et al (2022)

Forecasting Staphylococcus aureus Infections Using Genome-Wide Association Studies, Machine Learning, and Transcriptomic Approaches.

mSystems [Epub ahead of print].

Staphylococcus aureus is a major human and animal pathogen, colonizing diverse ecological niches within its hosts. Predicting whether an isolate will infect a specific host and its subsequent clinical fate remains unknown. In this study, we investigated the S. aureus pangenome using a curated set of 356 strains, spanning a wide range of hosts, origins, and clinical display and antibiotic resistance profiles. We used genome-wide association study (GWAS) and random forest (RF) algorithms to discriminate strains based on their origins and clinical sources. Here, we show that the presence of sak and scn can discriminate strains based on their host specificity, while other genes such as mecA are often associated with virulent outcomes. Both GWAS and RF indicated the importance of intergenic regions (IGRs) and coding DNA sequence (CDS) but not sRNAs in forecasting an outcome. Additional transcriptomic analyses performed on the most prevalent clonal complex 8 (CC8) clonal types, in media mimicking nasal colonization or bacteremia, indicated three RNAs as potential RNA markers to forecast infection, followed by 30 others that could serve as infection severity predictors. Our report shows that genetic association and transcriptomics are complementary approaches that will be combined in a single analytical framework to improve our understanding of bacterial pathogenesis and ultimately identify potential predictive molecular markers. IMPORTANCE Predicting the outcome of bacterial colonization and infections, based on extensive genomic and transcriptomic data from a given pathogen, would be of substantial help for clinicians in treating and curing patients. In this report, genome-wide association studies and random forest algorithms have defined gene combinations that differentiate human from animal strains, colonization from diseases, and nonsevere from severe diseases, while it revealed the importance of IGRs and CDS, but not small RNAs (sRNAs), in anticipating an outcome. In addition, transcriptomic analyses performed on the most prevalent clonal types, in media mimicking either nasal colonization or bacteremia, revealed significant differences and therefore potent RNA markers. Overall, the use of both genomic and transcriptomic data in a single analytical framework can enhance our understanding of bacterial pathogenesis.

RevDate: 2022-08-03

Baseggio L, Silayeva O, Engelstädter J, et al (2022)

The Evolution of a Specialized, Highly Virulent Fish Pathogen through Gene Loss and Acquisition of Host-Specific Survival Mechanisms.

Applied and environmental microbiology, 88(14):e0022222.

Photobacterium damselae comprises two subspecies, P. damselae subsp. damselae and P. damselae subsp. piscicida, that contrast remarkably despite their taxonomic relationship. The former is opportunistic and free-living but can cause disease in compromised individuals from a broad diversity of taxa, while the latter is a highly specialized, primary fish pathogen. Here, we employ new closed curated genome assemblies from Australia to estimate the global phylogenetic structure of the species P. damselae. We identify genes responsible for the shift from an opportunist to a host-adapted fish pathogen, potentially via an arthropod vector as fish-to-fish transmission was not achieved in repeated cohabitation challenges despite high virulence for Seriola lalandi. Acquisition of ShdA adhesin and of thiol peroxidase may have allowed the environmental, generalist ancestor to colonize zooplankton and to occasionally enter in fish host sentinel cells. As dependence on the host has increased, P. damselae has lost nonessential genes, such as those related to nitrite and sulfite reduction, urea degradation, a type 6 secretion system (T6SS) and several toxin-antitoxin (TA) systems. Similar to the evolution of Yersinia pestis, the loss of urease may be the crucial event that allowed the pathogen to stably colonize zooplankton vectors. Acquisition of host-specific genes, such as those required to form a sialic acid capsule, was likely necessary for the emergent P. damselae subsp. piscicida to become a highly specialized, facultative intracellular fish pathogen. Processes that have shaped P. damselae subsp. piscicida from subsp. damselae are similar to those underlying evolution of Yersinia pestis from Y. pseudotuberculosis. IMPORTANCE Photobacterium damselae subsp. damselae is a ubiquitous marine bacterium and opportunistic pathogen of compromised hosts of diverse taxa. In contrast, its sister subspecies P. damselae subsp. piscicida (Pdp) is highly virulent in fish. Pdp has evolved from a single subclade of Pdd through gene loss and acquisition. We show that fish-to-fish transmission does not occur in repeated infection models in the primary host, Seriola lalandi, and present genomic evidence for vector-borne transmission, potentially via zooplankton. The broad genomic changes from generalist Pdd to specialist Pdp parallel those of the environmental opportunist Yersinia pseudotuberculosis to vector-borne plague bacterium Y. pestis and demonstrate that evolutionary processes in bacterial pathogens are universal between the terrestrial and marine biosphere.

RevDate: 2022-07-21

Jonkheer EM, van Workum DM, Sheikhizadeh Anari S, et al (2022)

PanTools v3: functional annotation, classification, and phylogenomics.

Bioinformatics (Oxford, England) pii:6647839 [Epub ahead of print].

SUMMARY: The ever-increasing number of sequenced genomes necessitates the development of pangenomic approaches for comparative genomics. Introduced in 2016, PanTools is a platform that allows pangenome construction, homology grouping and pangenomic read mapping. The use of graph database technology makes PanTools versatile, applicable from small viral genomes like SARS-CoV-2 up to large plant or animal genomes like tomato or human. Here we present our third major update to PanTools that enables the integration of functional annotations and provides both gene-level analyses and phylogenetics.

PanTools is implemented in Java 8 and released under the GNU GPLv3 license. Software and documentation are available at

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2022-07-20

Guitart-Matas J, Gonzalez-Escalona N, Maguire M, et al (2022)

Revealing Genomic Insights of the Unexplored Porcine Pathogen Actinobacillus pleuropneumoniae Using Whole Genome Sequencing.

Microbiology spectrum [Epub ahead of print].

Actinobacillus pleuropneumoniae (APP) is the causative agent of pleuropneumonia in pigs, one of the most relevant bacterial respiratory diseases in the swine industry. To date, 19 serotypes have been described based on capsular polysaccharide typing with significant virulence dissimilarities. In this study, 16 APP isolates from Spanish origin were selected to perform antimicrobial susceptibility tests and comparative genomic analysis using whole genome sequencing (WGS). To obtain a more comprehensive worldwide molecular epidemiologic analyses, all APP whole genome assemblies available at the National Center for Biotechnology Information (NCBI) at the time of the study were also included. An in-house in silico PCR approach enabled the correct serotyping of unserotyped or incorrectly serotyped isolates and allowed for the discrimination between serotypes 9 and 11. A pangenome analysis identified the presence or absence of gene clusters to be serotype specific, as well as virulence profile analyses targeting the apx operons. Antimicrobial resistance genes were correlated to the presence of specific plasmids. Altogether, this study provides new insights into the genetic variability within APP serotypes, correlates phenotypic tests with bioinformatic analyses and manifests the benefits of populated databases for a better assessment of diversity and variability of relatively unknown pathogens. Overall, genomic comparative analysis enhances the understanding of transmission and epidemiological patterns of this species and suggests vertical transmission of the pathogen, including the resistance genes, within the Spanish integrated systems. IMPORTANCE Pleuropneumonia is one of the most relevant respiratory infections in the swine industry. Despite Actinobacillus pleuropneumoniae (APP) being one of the most important pathogens in the pig production, this is the first comparative study including all available whole genome sequencing data from NCBI. Moreover, this study also includes 16 APP isolates of Spanish origin with known epidemiological relationships through vertical integrated systems. Genomic comparisons provided a deeper understanding of molecular and epidemiological knowledge between different APP serotypes. Furthermore, determination of resistance and toxin profiles allowed correlation with the presence of mobile genetic elements and specific serotype, respectively.

RevDate: 2022-07-20

Babiker A, Bower C, Lutgring JD, et al (2022)

Clinical and Genomic Epidemiology of mcr-9-Carrying Carbapenem-Resistant Enterobacterales Isolates in Metropolitan Atlanta, 2012 to 2017.

Microbiology spectrum [Epub ahead of print].

Colistin is a last-resort antibiotic for multidrug-resistant Gram-negative infections. Recently, the ninth allele of the mobile colistin resistance (mcr) gene family, designated mcr-9, was reported. However, its clinical and public health significance remains unclear. We queried genomes of carbapenem-resistant Enterobacterales (CRE) for mcr-9 from a convenience sample of clinical isolates collected between 2012 and 2017 through the Georgia Emerging Infections Program, a population- and laboratory-based surveillance program. Isolates underwent phenotypic characterization and whole-genome sequencing. Phenotypic characteristics, genomic features, and clinical outcomes of mcr-9-positive and -negative CRE cases were then compared. Among 235 sequenced CRE genomes, 13 (6%) were found to harbor mcr-9, all of which were Enterobacter cloacae complex. The median MIC and rates of heteroresistance and inducible resistance to colistin were similar between mcr-9-positive and -negative isolates. However, rates of resistance were higher among mcr-9-positive isolates across most antibiotic classes. All cases had significant health care exposures. The 90-day mortality was similarly high in both mcr-9-positive (31%) and -negative (7%) CRE cases. Nucleotide identity and phylogenetic analysis did not reveal geotemporal clustering. mcr-9-positive isolates had a significantly higher number of median [range] antimicrobial resistance (AMR) genes (16 [4 to 22] versus 6 [2 to 15]; P < 0.001) than did mcr-9-negative isolates. Pangenome tests confirmed a significant association of mcr-9 detection with mobile genetic element and heavy metal resistance genes. Overall, the presence of mcr-9 was not associated with significant changes in colistin resistance or clinical outcomes, but continued genomic surveillance to monitor for emergence of AMR genes is warranted. IMPORTANCE Colistin is a last-resort antibiotic for multidrug-resistant Gram-negative infections. A recently described allele of the mobile colistin resistance (mcr) gene family, designated mcr-9, has been widely reported among Enterobacterales species. However, its clinical and public health significance remains unclear. We compared characteristics and outcomes of mcr-9-positive and -negative CRE cases. All cases were acquired in the health care setting and associated with a high rate of mortality. The presence of mcr-9 was not associated with significant changes in colistin resistance, heteroresistance, or inducible resistance but was associated with resistance to other antimicrobials and antimicrobial resistance (AMR), virulence, and heavy metal resistance (HMR) genes. Overall, the presence of mcr-9 was not associated with significant phenotypic changes or clinical outcomes. However, given the increase in AMR and HMR gene content and potential clinical impact, continued genomic surveillance of multidrug-resistant organisms to monitor for emergence of AMR genes is warranted.

RevDate: 2022-07-19

Wang Y, Du F, Wang J, et al (2022)

Improving bread wheat yield through modulating an unselected AP2/ERF gene.

Nature plants [Epub ahead of print].

Crop breeding heavily relies on natural genetic variation. However, additional new variations are desired to meet the increasing human demand. Inflorescence architecture determines grain number per spike, a major determinant of bread wheat (Triticum aestivum L.) yield. Here, using Brachypodium distachyon as a wheat proxy, we identified DUO-B1, encoding an APETALA2/ethylene response factor (AP2/ERF) transcription factor, regulating spike inflorescence architecture in bread wheat. Mutations of DUO-B1 lead to mild supernumerary spikelets, increased grain number per spike and, importantly, increased yield under field conditions without affecting other major agronomic traits. DUO-B1 suppresses cell division and promotes the expression of BHt/WFZP, whose mutations could lead to branched 'miracle-wheat'. Pan-genome analysis indicated that DUO-B1 has not been utilized in breeding, and holds promise to increase wheat yield further.

RevDate: 2022-07-16

Liu Y, Z Tian (2022)

Super graph-based pan-genome: bring rice functional genomic study into a new dawn.

Molecular plant pii:S1674-2052(22)00225-8 [Epub ahead of print].

RevDate: 2022-08-01

Ksiezarek M, Grosso F, Ribeiro TG, et al (2022)

Genomic diversity of genus Limosilactobacillus.

Microbial genomics, 8(7):.

RevDate: 2022-07-16

Zaidi SE, Zaheer R, Barbieri R, et al (2022)

Genomic Characterization of Enterococcus hirae From Beef Cattle Feedlots and Associated Environmental Continuum.

Frontiers in microbiology, 13:859990.

Enterococci are commensal bacteria of the gastrointestinal tract of humans, animals, and insects. They are also found in soil, water, and plant ecosystems. The presence of enterococci in human, animal, and environmental settings makes these bacteria ideal candidates to study antimicrobial resistance in the One-Health continuum. This study focused on Enterococcus hirae isolates (n = 4,601) predominantly isolated from beef production systems including bovine feces (n = 4,117, 89.5%), catch-basin water (n = 306, 66.5%), stockpiled bovine manure (n = 24, 0.5%), and natural water sources near feedlots (n = 145, 32%), and a few isolates from urban wastewater (n = 9, 0.2%) denoted as human-associated environmental samples. Antimicrobial susceptibility profiling of a subset (n = 1,319) of E. hirae isolates originating from beef production systems (n = 1,308) showed high resistance to tetracycline (65%) and erythromycin (57%) with 50.4% isolates harboring multi-drug resistance, whereas urban wastewater isolates (n = 9) were resistant to nitrofurantoin (44.5%) and tigecycline (44.5%) followed by linezolid (33.3%). Genes for tetracycline (tetL, M, S/M, and O/32/O) and macrolide resistance erm(B) were frequently found in beef production isolates. Antimicrobial resistance profiles of E. hirae isolates recovered from different environmental settings appeared to reflect the kind of antimicrobial usage in beef and human sectors. Comparative genomic analysis of E. hirae isolates showed an open pan-genome that consisted of 1,427 core genes, 358 soft core genes, 1701 shell genes, and 7,969 cloud genes. Across species comparative genomic analysis conducted on E. hirae, Enterococcus faecalis and Enterococcus faecium genomes revealed that E. hirae had unique genes associated with vitamin production, cellulose, and pectin degradation, traits which may support its adaptation to the bovine digestive tract. E. faecium and E. faecalis more frequently harbored virulence genes associated with biofilm formation, iron transport, and cell adhesion, suggesting niche specificity within these species.

RevDate: 2022-07-13

Shang L, Li X, He H, et al (2022)

A super pan-genomic landscape of rice.

Cell research [Epub ahead of print].

Pan-genomes from large natural populations can capture genetic diversity and reveal genomic complexity. Using de novo long-read assembly, we generated a graph-based super pan-genome of rice consisting of a 251-accession panel comprising both cultivated and wild species of Asian and African rice. Our pan-genome reveals extensive structural variations (SVs) and gene presence/absence variations. Additionally, our pan-genome enables the accurate identification of nucleotide-binding leucine-rich repeat genes and characterization of their inter- and intraspecific diversity. Moreover, we uncovered grain weight-associated SVs which specify traits by affecting the expression of their nearby genes. We characterized genetic variants associated with submergence tolerance, seed shattering and plant architecture and found independent selection for a common set of genes that drove adaptation and domestication in Asian and African rice. This super pan-genome facilitates pinpointing of lineage-specific haplotypes for trait-associated genes and provides insights into the evolutionary events that have shaped the genomic architecture of various rice species.

RevDate: 2022-07-12

Olsen KM (2022)

The rice pangenome branches out.

Cell research [Epub ahead of print].

RevDate: 2022-07-13
CmpDate: 2022-07-13

Contreras-Moreira B, Del Río ÁR, Cantalapiedra CP, et al (2022)

Pangenome Analysis of Plant Transcripts and Coding Sequences.

Methods in molecular biology (Clifton, N.J.), 2512:121-152.

The pangenome of a species is the sum of the genomes of its individuals. As coding sequences often represent only a small fraction of each genome, analyzing the pangene set can be a cost-effective strategy for plants with large genomes or highly heterozygous species. Here, we describe a step-by-step protocol to analyze plant pangene sets with the software GET_HOMOLOGUES-EST . After a short introduction, where the main concepts are illustrated, the remaining sections cover the installation and typical operations required to analyze and annotate pantranscriptomes and gene sets of plants. The recipes include instructions on how to call core and accessory genes, how to compute a presence-absence pangenome matrix, and how to identify and analyze private genes, present only in some genotypes. Downstream phylogenetic analyses are also discussed.

RevDate: 2022-07-13
CmpDate: 2022-07-13

Tay Fernandez CG, Marsh JI, Nestor BJ, et al (2022)

An SGSGeneloss-Based Method for Constructing a Gene Presence-Absence Table Using Mosdepth.

Methods in molecular biology (Clifton, N.J.), 2512:73-80.

Presence-absence variants (PAV) are genomic regions present in some individuals of a species, but not others. PAVs have been shown to contribute to genomic diversity, especially in bacteria and plants. These structural variations have been linked to traits and can be used to track a species' evolutionary history. PAVs are usually called by aligning short read sequence data from one or more individuals to a reference genome or pangenome assembly, and then comparing coverage. Regions where reads do not align define absence in that individual, and the regions are classified as PAVs. The method below details how to align sequence reads to a reference and how to use the sequencing-coverage calculator Mosdepth to identify PAVs and construct a PAV table for use in downstream comparative genome analysis.

RevDate: 2022-07-11

González-Díaz A, Berbel D, Ercibengoa M, et al (2022)

Genomic features of predominant non-PCV13 serotypes responsible for adult invasive pneumococcal disease in Spain.

The Journal of antimicrobial chemotherapy pii:6639590 [Epub ahead of print].

BACKGROUND: Although pneumococcal conjugate vaccines (PCVs) effectively prevent invasive pneumococcal disease (IPD), serotype replacement has occurred.

OBJECTIVES: We studied the pangenome, antibiotic resistance mechanisms and presence of mobile elements in predominant non-PCV13 serotypes causing adult IPD after PCV13 vaccine introduction in Spain.

METHODS: We conducted a multicentre study comparing three periods in six Spanish hospitals and analysed through whole genome sequencing representative strains collected in the pre-PCV13, early-PCV13 and late-PCV13 periods.

RESULTS: Among 2197 cases of adult IPD identified, 110 pneumococci expressing non-PCV13 capsules were sequenced. Seven predominant serotypes accounted for 42.6% of IPD episodes in the late-PCV13 period: serotypes 8 (14.4%), 12F (7.5%), 9N (5.2%), 11A (4.1%), 22F (3.9%), 24F (3.9%) and 16F (3.6%). All predominant non-PCV13 serotypes were highly clonal, comprising one or two clonal complexes (CC). In general, CC538, CC4048, CC3016F, CC43322F and CC669N, related to predominant non-PCV13 serotypes, were antibiotic susceptible. CC15611A was associated with resistance to co-trimoxazole, penicillin and amoxicillin. CC23024F was non-susceptible to penicillin and resistant to erythromycin, clindamycin, and tetracycline. Six composite transposon structures of the Tn5252-family were found in CC23024F, CC98912F and CC3016F carrying different combinations of erm(B), tet(M), and cat. Pangenome analysis revealed differences in accessory genomes among the different CC, with most variety in CC3016F (23.9%) and more conservation in CC15611A (8.5%).

CONCLUSIONS: We identified highly clonal predominant serotypes responsible for IPD in adults. The detection of not only conjugative elements carrying resistance determinants but also clones previously associated with vaccine serotypes (CC15611A and CC23024F) highlights the importance of the accessory genome.

RevDate: 2022-08-03

Yang T, F Gao (2022)

High-quality pan-genome of Escherichia coli generated by excluding confounding and highly similar strains reveals an association between unique gene clusters and genomic islands.

Briefings in bioinformatics, 23(4):.

The pan-genome analysis of bacteria provides detailed insight into the diversity and evolution of a bacterial population. However, the genomes involved in the pan-genome analysis should be checked carefully, as the inclusion of confounding strains would have unfavorable effects on the identification of core genes, and the highly similar strains could bias the results of the pan-genome state (open versus closed). In this study, we found that the inclusion of highly similar strains also affects the results of unique genes in pan-genome analysis, which leads to a significant underestimation of the number of unique genes in the pan-genome. Therefore, these strains should be excluded from pan-genome analysis at the early stage of data processing. Currently, tens of thousands of genomes have been sequenced for Escherichia coli, which provides an unprecedented opportunity as well as a challenge for pan-genome analysis of this classical model organism. Using the proposed strategies, a high-quality E. coli pan-genome was obtained, and the unique genes was extracted and analyzed, revealing an association between the unique gene clusters and genomic islands from a pan-genome perspective, which may facilitate the identification of genomic islands.

RevDate: 2022-07-16
CmpDate: 2022-07-12

Alshammari A, Alharbi M, Alghamdi A, et al (2022)

Computer-Aided Multi-Epitope Vaccine Design against Enterobacter xiangfangensis.

International journal of environmental research and public health, 19(13):.

Antibiotic resistance is a global public health threat and is associated with high mortality due to antibiotics' inability to treat bacterial infections. Enterobacter xiangfangensis is an emerging antibiotic-resistant bacterial pathogen from the Enterobacter genus and has the ability to acquire resistance to multiple antibiotic classes. Currently, there is no effective vaccine against Enterobacter species. In this study, a chimeric vaccine is designed comprising different epitopes screened from E. xiangfangensis proteomes using immunoinformatic and bioinformatic approaches. In the first phase, six fully sequenced proteomes were investigated by bacterial pan-genome analysis, which revealed that the pathogen consists of 21,996 core proteins, 3785 non-redundant proteins and 18,211 redundant proteins. The non-redundant proteins were considered for the vaccine target prioritization phase where different vaccine filters were applied. By doing so, two proteins; ferrichrome porin (FhuA) and peptidoglycan-associated lipoprotein (Pal) were shortlisted for epitope prediction. Based on properties of antigenicity, allergenicity, water solubility and DRB*0101 binding ability, three epitopes (GPAPTIAAKR, ATKTDTPIEK and RNNGTTAEI) were used in multi-epitope vaccine designing. The designed vaccine construct was analyzed in a docking study with immune cell receptors, which predicted the vaccine's proper binding with said receptors. Molecular dynamics analysis revealed that the vaccine demonstrated stable binding dynamics, and binding free energy calculations further validated the docking results. In conclusion, these in silico results may help experimentalists in developing a vaccine against E. xiangfangensis in specific and Enterobacter in general.

RevDate: 2022-07-23

Saraiva MMS, Benevides VP, da Silva NMV, et al (2022)

Genomic and Evolutionary Analysis of Salmonella enterica Serovar Kentucky Sequence Type 198 Isolated From Livestock In East Africa.

Frontiers in cellular and infection microbiology, 12:772829.

Since its emergence in the beginning of the 90's, multidrug-resistant (MDR) Salmonella enterica subsp. enterica serovar Kentucky has become a significant public health problem, especially in East Africa. This study aimed to investigate the antimicrobial resistance profile and the genotypic relatedness of Salmonella Kentucky isolated from animal sources in Ethiopia and Kenya (n=19). We also investigated population evolutionary dynamics through phylogenetic and pangenome analyses with additional publicly available Salmonella Kentucky ST198 genomes (n=229). All the 19 sequenced Salmonella Kentucky isolates were identified as ST198. Among these isolates, the predominant genotypic antimicrobial resistance profile observed in ten (59.7%) isolates included the aac(3)-Id, aadA7, strA-strB, bla TEM-1B, sul1, and tet(A) genes, which mediated resistance to gentamicin, streptomycin/spectinomycin, streptomycin, ampicillin, sulfamethoxazole and tetracycline, respectively; and gyrA and parC mutations associated to ciprofloxacin resistance. Four isolates harbored plasmid types Incl1 and/or Col8282; two of them carried both plasmids. Salmonella Pathogenicity islands (SPI-1 to SPI-5) were highly conserved in the 19 sequenced Salmonella Kentucky isolates. Moreover, at least one Pathogenicity Island (SPI 1-4, SPI 9 or C63PI) was identified among the 229 public Salmonella Kentucky genomes. The phylogenetic analysis revealed that almost all Salmonella Kentucky ST198 isolates (17/19) stemmed from a single strain that has accumulated ciprofloxacin resistance-mediating mutations. A total of 8,104 different genes were identified in a heterogenic and still open Salmonella Kentucky ST198 pangenome. Considering the virulence factors and antimicrobial resistance genes detected in Salmonella Kentucky, the implications of this pathogen to public health and the epidemiological drivers for its dissemination must be investigated.

RevDate: 2022-07-02

Garg G, Kamphuis LG, Bayer PE, et al (2022)

A pan-genome and chromosome-length reference genome of narrow-leafed lupin (Lupinus angustifolius) reveals genomic diversity and insights into key industry and biological traits.

The Plant journal : for cell and molecular biology [Epub ahead of print].

Narrow-leafed lupin (NLL; Lupinus angustifolius) is a key rotational crop for sustainable farming systems, whose grain is high in protein content. It is a gluten-free, non-GM, alternative protein source to soybean and as such has gained an interest as a human food ingredient. Here, we present a chromosome-length reference genome for the species and a pan-genome assembly comprising 55 NLL lines including, Australian and European cultivars, breeding lines and wild accessions. We present the core and variable genes for the species and report on the absence of essential mycorrhizal associated genes. The genome and pan-genomes of NLL and its close relative white lupin (L. albus) are compared. Furthermore, we provide additional evidence supporting LaRAP2-7 as the key alkaloid regulatory gene for NLL and demonstrate the NLL genome is underrepresented in classical NLR disease resistance genes compared to other sequenced legume species. The NLL genomic resources generated here coupled with previously generated RNA-seq datasets provide new opportunities to fast-track lupin crop improvement.

RevDate: 2022-07-21

Sang J, Zhuang D, Zhang T, et al (2022)

Convergent and Divergent Age Patterning of Gut Microbiota Diversity in Humans and Nonhuman Primates.

mSystems [Epub ahead of print].

The gut microbiome has significant effects on healthy aging and aging-related diseases, whether in humans or nonhuman primates. However, little is known about the divergence and convergence of gut microbial diversity between humans and nonhuman primates during aging, which limits their applicability for studying the gut microbiome's role in human health and aging. Here, we performed 16S rRNA gene sequencing analysis for captive rhesus macaques (Macaca mulatta) and compared this data set with other freely available gut microbial data sets containing four human populations (Chinese, Japanese, Italian, and British) and two nonhuman primates (wild lemurs [Lemur catta] and wild chimpanzees [Pan troglodytes]). Based on the consistent V4 region of the 16S rRNA gene, beta diversity analysis suggested significantly separated gut microbial communities associated with host backgrounds of seven host groups, but within each group, significant gut microbial divergences were observed, and indicator bacterial genera were identified as associated with aging. We further discovered six common anti-inflammatory gut bacteria (Prevotellamassilia, Prevotella, Gemmiger, Coprococcus, Faecalibacterium, and Roseburia) that had butyrate-producing potentials suggested by pangenomic analysis and that showed similar dynamic changes in at least two selected host groups during aging, independent of distinct host backgrounds. Finally, we found striking age-related changes in 66 plasma metabolites in macaques. Two highly changed metabolites, hydroxyproline and leucine, enriched in adult macaques were significantly and positively correlated with Prevotella and Prevotellamassilia. Furthermore, genus-level pangenome analysis suggested that those six common indicator bacteria can synthesize leucine and arginine as hydroxyproline and proline precursors in both humans and macaques. IMPORTANCE This study provides the first comprehensive investigation of age patterning of gut microbiota of four human populations and three nonhuman primates and found that Prevotellamassilia, Prevotella, Gemmiger, Coprococcus, Faecalibacterium, and Roseburia may be common antiaging microbial markers in both humans and nonhuman primates due to their potential metabolic capabilities for host health benefits. Our results also provide key support for using macaques as animal models in studies of the gut microbiome's role during human aging.

RevDate: 2022-07-15

Liu C, Wang Y, Peng J, et al (2022)

High-quality genome assembly and pan-genome studies facilitate genetic discovery in mung bean and its improvement.

Plant communications pii:S2590-3462(22)00107-9 [Epub ahead of print].

Mung bean is an economically important legume crop species that is used as a food, consumed as a vegetable, and used as an ingredient and even as a medicine. To explore the genomic diversity of mung bean, we assembled a high-quality reference genome (Vrad_JL7) that was ∼479.35 Mb in size, with a contig N50 length of 10.34 Mb. A total of 40,125 protein-coding genes were annotated, representing ∼96.9% of the genetic region. We also sequenced 217 accessions, mainly landraces and cultivars from China, and identified 2,229,343 high-quality single-nucleotide polymorphisms (SNPs). Population structure revealed that the Chinese accessions diverged into two groups and were distinct from non-Chinese lines. Genetic diversity analysis based on genomic data from 750 accessions in 23 countries supported the hypothesis that mung bean was first domesticated in south Asia and introduced to east Asia probably through the Silk Road. We constructed the first pan-genome of mung bean germplasm and assembled 287.73 Mb of non-reference sequences. Among the genes, 83.1% were core genes and 16.9% were variable. Presence/absence variation (PAV) events of nine genes involved in the regulation of the photoperiodic flowering pathway were identified as being under selection during the adaptation process to promote early flowering in the spring. Genome-wide association studies (GWASs) revealed 2,912 SNPs and 259 gene PAV events associated with 33 agronomic traits, including a SNP in the coding region of the SWEET10 homolog (jg24043) involved in crude starch content and a PAV event in a large fragment containing 11 genes for color-related traits. This high-quality reference genome and pan-genome will provide insights into mung bean breeding.

RevDate: 2022-07-16
CmpDate: 2022-06-28

Guo G, Wang Z, Li Q, et al (2022)

Genomic characterization of Streptococcus parasuis, a close relative of Streptococcus suis and also a potential opportunistic zoonotic pathogen.

BMC genomics, 23(1):469.

Streptococcus parasuis (S. parasuis) is a close relative of Streptococcus suis (S. suis), composed of former members of S. suis serotypes 20, 22 and 26. S. parasuis could infect pigs and cows, and recently, human infection cases have been reported, making S. parasuis a potential opportunistic zoonotic pathogen. In this study, we analysed the genomic characteristics of S. parasuis, using pan-genome analysis, and compare some phenotypic determinants such as capsular polysaccharide, integrative conjugative elements, CRISPR-Cas system and pili, and predicted the potential virulence genes by associated analysis of the clinical condition of isolated source animals and genotypes. Furthermore, to discuss the relationship with S. suis, we compared these characteristics of S. parasuis with those of S. suis. We found that the characteristics of S. parasuis are similar to those of S. suis, both of them have "open" pan-genome, their antimicrobial resistance gene profiles are similar and a srtF pilus cluster of S. suis was identified in S. parasuis genome. But S. parasuis still have its unique characteristics, two novel pilus clusters are and three different type CRISPR-Cas system were found. Therefore, this study provides novel insights into the interspecific and intraspecific genetic characteristics of S. parasuis, which can be useful for further study of this opportunistic pathogen, such as serotyping, diagnostics, vaccine development, and study of the pathogenesis mechanism.

RevDate: 2022-06-25

Huang G, Y Zhu (2022)

Insights of section-wide pan-genome into hybrid potato breeding.

Science China. Life sciences [Epub ahead of print].

RevDate: 2022-07-26
CmpDate: 2022-07-26

Menghwar H, J Perez-Casal (2022)

Comparative genomic analysis of Canadian Mycoplasma bovis strains isolated from Bison and Cattle.

Comparative immunology, microbiology and infectious diseases, 87:101835.

Mycoplasma bovis (M. bovis) in cattle causes pneumonia, arthritis, otitis media, and mastitis. In addition, multiple outbreaks have been recorded in North American bison. The genomic data on Canadian M. bovis in bison and cattle to date is limited. Whole-genome sequencing (WGS) was used to assess the degree of genome conservation across four Canadian M. bovis strains recovered from bison and cattle. Whole-genome sequences of four M. bovis isolates (Mb1, Mb160, Mb300, Mb304) and the PG45 reference genome were utilized to identify the M. bovis genomic similarity, whole-genome single nucleotide polymorphism (WGS-SNP), virulence determinants, and genomic islands. The pan-genome analysis showed that M. bovis encodes a minimum of 971 genes, while the core genome contained 637 genes. Comparative genomics revealed limited diversity in gene content between bison and cattle isolates. Whole-genome SNP analysis showed that the four M. bovis isolates differed from each other and to PG45. A total of 40 putative virulence genes associated with adhesion, colonization, and destruction of tissues were found in the bison and cattle isolates using the virulence factors database (VFDB). These putative virulence factors were equally distributed among isolates. Genomic Islands (GIs) ranging from 4 to 9 and associated with transposases, restriction-modification, ribosomal hypothetical proteins, variable surface lipoproteins, and unknowns were also identified. Overall, the genomic characterization of these isolates may provide new insights into the mechanisms of pathogenicity in M. bovis.

RevDate: 2022-08-01

Kutyna DR, Onetto CA, Williams TC, et al (2022)

Construction of a synthetic Saccharomyces cerevisiae pan-genome neo-chromosome.

Nature communications, 13(1):3628.

The Synthetic Yeast Genome Project (Sc2.0) represents the first foray into eukaryotic genome engineering and a framework for designing and building the next generation of industrial microbes. However, the laboratory strain S288c used lacks many of the genes that provide phenotypic diversity to industrial and environmental isolates. To address this shortcoming, we have designed and constructed a neo-chromosome that contains many of these diverse pan-genomic elements and which is compatible with the Sc2.0 design and test framework. The presence of this neo-chromosome provides phenotypic plasticity to the Sc2.0 parent strain, including expanding the range of utilizable carbon sources. We also demonstrate that the induction of programmable structural variation (SCRaMbLE) provides genetic diversity on which further adaptive gains could be selected. The presence of this neo-chromosome within the Sc2.0 backbone may therefore provide the means to adapt synthetic strains to a wider variety of environments, a process which will be vital to transitioning Sc2.0 from the laboratory into industrial applications.

RevDate: 2022-06-24

Li W, Liu J, Zhang H, et al (2022)

Plant pan-genomics: recent advances, new challenges, and roads ahead.

Journal of genetics and genomics = Yi chuan xue bao pii:S1673-8527(22)00162-X [Epub ahead of print].

Pan-genomics can encompass most of the genetic diversity of a species or population and has proved to be a powerful tool for studying genomic evolution and the origin and domestication of species, and for providing information for plant improvement. Plant genomics has greatly progressed because of improvements in sequencing technologies and the rapid reduction of sequencing costs. Nevertheless, pan-genomics still presents many challenges, including computationally intensive assembly methods, high costs with large numbers of samples, ineffective integration of big data, and difficulty in applying it to downstream multi-omics analysis and breeding research. In this review, we summarize the definition and recent achievements of plant pan-genomics, computational technologies used for pan-genome construction, and the applications of pan-genomes in plant genomics and molecular breeding. We also discuss challenges and perspectives for future pan-genomics studies and provide a detailed pipeline for sample selection, genome assembly and annotation, structural variation identification, and construction and application of graph-based pan-genomes. The aim is to provide important guidance for plant pan-genome research and a better understanding of the genetic basis of genome evolution, crop domestication, and phenotypic diversity for future studies.

RevDate: 2022-06-24

Bradbury PJ, Casstevens T, Jensen SE, et al (2022)

The Practical Haplotype Graph, a platform for storing and using pangenomes for imputation.

Bioinformatics (Oxford, England) pii:6617344 [Epub ahead of print].

MOTIVATION: Pangenomes provide novel insights for population and quantitative genetics, genomics, and breeding not available from studying a single reference genome. Instead, a species is better represented by a pangenome or collection of genomes. Unfortunately, managing and using pangenomes for genomically diverse species is computationally and practically challenging. We developed a trellis graph representation anchored to the reference genome that represents most pangenomes well and can be used to impute complete genomes from low density sequence or variant data.

RESULTS: The Practical Haplotype Graph (PHG) is a pangenome pipeline, database (PostGRES & SQLite), data model (Java, Kotlin, or R), and Breeding API (BrAPI) web service. The PHG has already been able to accurately represent diversity in four major crops including maize, one of the most genomically diverse species, with up to 1000-fold data compression. Using simulated data, we show that, at even 0.1X coverage, with appropriate reads and sequence alignment, imputation results in extremely accurate haplotype reconstruction. The PHG is a platform and environment for the understanding and application of genomic diversity.

AVAILABILITY: All resources listed here are freely available. The PHG Docker used to generate the simulation results is as maizegenetics/phg:0.0.27. PHG source code is at The code used for the analysis of simulated data is at The PHG database of NAM parent haplotypes is in the CyVerse data store ( and named /iplant/home/shared/panzea/panGenome/PHG_db_maize/phg_v5Assemblies_20200608.db.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2022-07-21

Chandrasekar SS, Phanse Y, Riel M, et al (2022)

Systemic Neutralizing Antibodies and Local Immune Responses Are Critical for the Control of SARS-CoV-2.

Viruses, 14(6):.

Antibody measurements are primarily used to evaluate experimental and approved COVID-19 vaccines, which is unilateral considering our immune responses' complex nature. Previously, we showed that nanoparticle plasmid DNA adjuvant system, QAC, and MVA based vaccines were immunogenic against SARS-CoV-2. Here, we report on the protective efficacy of systemic humoral and mucosal cell-mediated immune responses in transgenic mice models against SARS-CoV-2 following nanoparticle immunization. Parenteral, intramuscular administration of QAC-based plasmid DNA vaccine-encoding SARS-CoV-2 S and N led to the induction of significant serum neutralizing humoral responses, which reduced viral burden in the lungs and prevented viral dissemination to the brain. In contrast, the mucosal, intranasal administration of a heterologous vaccine elicited significant mucosal cell-mediated immune responses in the lungs that limited lung viral replication. The presented results demonstrate that serum neutralizing humoral and local lung T-cell immune responses are critical for the control of SARS-CoV-2 replication.

RevDate: 2022-07-16

Al-Megrin WAI, Karkashan A, Alnuqaydan AM, et al (2022)

Design of a Multi-Epitopes Based Chimeric Vaccine against Enterobacter cloacae Using Pan-Genome and Reverse Vaccinology Approaches.

Vaccines, 10(6):.

Enterobacter cloacae (EC) is a significant emerging pathogen that is occasionally associated with lung infection, surgical site infection, urinary infection, sepsis, and outbreaks in neonatal intensive care units. In light of the fact that there is currently no approved vaccine or therapeutic option for the treatment of EC, the current study was developed to concentrate on applications based on modern computational approaches to design a multi-epitope-based E. cloacae peptide vaccine (MEBEPV) expressing the antigenic determinants prioritized from the EC genome. Integrated computational analyses identified two potential protein targets (phosphoporin protein-PhoE and putative outer-membrane porin protein) for further exploration on the basis of pangenome subtractive proteomics and immunoinformatic in-depth examination of the core proteomes. Then, a multi-epitope peptide vaccine was designed, which comprised shortlisted epitopes that were capable of eliciting both innate and adaptive immunity, as well as the cholera toxin's B-subunit, which was used as an adjuvant in the vaccine formulation. To ensure maximum expression, the vaccine's 3D structure was developed and the loop was refined, improving the stability by disulfide engineering, and the physicochemical characteristics of the recombinant vaccine sequence were found to be ideal for both in vitro and in vivo experimentation. Blind docking was then used for the prediction of the MEBEPV predominant blinding mode with MHCI, MHCII, and TLR3 innate immune receptors, with lowest global energy of -18.64 kJ/mol, -48.25 kJ/mol, and -5.20 kJ/mol for MHC-I, MHC-II, and TLR-4, respectively, with docked complexes considered for simulation. In MD and MMGBSA investigations, the docked models of MEBEPV-TLR3, MEBEPV-MHCI, and MEBEPV-MHCII were found to be stable during the course of the simulation. MM-GBSA analysis calculated -122.17 total net binding free energies for the TLR3-vaccine complex, -125.4 for the MHC I-vaccine complex, and -187.94 for the MHC II-vaccine complex. Next, MM-PBSA analysis calculated -115.63 binding free energy for the TLR3-vaccine complex, -118.19 for the MHC I-vaccine complex, and -184.61 for the MHC II-vaccine complex. When the vaccine was tested in silico, researchers discovered that it was capable of inducing both types of immune responses (cell mediated and humoral) at the same time. Even though the suggested MEBEPV has the potential to be a powerful contender against E. cloacae-associated illnesses, further testing in the laboratory will be required before it can be declared safe and immunogenic.

RevDate: 2022-07-16

Jungkhun N, Gomes de Farias AR, Watcharachaiyakup J, et al (2022)

Phylogenetic Characterization and Genome Sequence Analysis of Burkholderia glumae Strains Isolated in Thailand as the Causal Agent of Rice Bacterial Panicle Blight.

Pathogens (Basel, Switzerland), 11(6):.

Burkholderia glumae is one of the most critical rice-pathogenic bacteria, and it causes bacterial panicle blight (BPB) in rice plants. In 2017, BPB symptoms were observed from rice fields in Chiang Rai, Northern Thailand. Sixty-one isolates obtained from the symptomatic panicles of rice were initially identified as B. glumae by polymerase chain reaction (PCR) using species-specific primers. Among them, six selected strains isolated from the susceptible japonica rice cultivar DOA2 were characterized in terms of morpho-physiology, pathology, phylogenetics, and genomics. Our genome sequence analysis of the six selected strains revealed the presence of multiple prophages, which may reflect the high level of diversity in this bacterial species through dynamic horizontal gene transfer processes, including phage infection. This notion was supported by the results of phylogenetic and phylogenomic analyses, which showed the formation of several subgroups not related to the years of isolation or the geographical origins. This study reports the isolation of B. glumae as the causal pathogen of BPB disease in japonica rice in Thailand and provides genomic resources to better understand the biology and diversity of this plant pathogenic bacterium. Further studies with a vast collection of B. glumae strains from various rice-growing regions around the world are needed to elucidate the evolution, variability, and lifestyle of the pathogen.

RevDate: 2022-07-16

Guo Y, Liu Z, Fu Y, et al (2022)

Pan-Genomes Provide Insights into the Genetic Basis of Auricularia heimuer Domestication.

Journal of fungi (Basel, Switzerland), 8(6):.

In order to reveal the genetic variation signals of Auricularia heimuer that have occurred during their domestication and to find potential functional gene families, we constructed a monokaryotic pan-genome of A. heimuer representing four cultivated strains and four wild strains. The pan-genome contained 14,089 gene families, of which 67.56% were core gene families and 31.88% were dispensable gene families. We screened substrate utilization-related genes such as the chitinase gene ahchi1 of the glycoside hydrolase (GH) 18 family and a carbohydrate-binding module (CBM)-related gene from the dispensable families of cultivated populations. The genomic difference in the ahchi1 gene between the wild and cultivated genomes was caused by a 33 kb presence/absence variation (PAV). The detection rate of the ahchi1 gene was 93.75% in the cultivated population, significantly higher than that in the wild population (17.39%), indicating that it has been selected in cultivated strains. Principal component analysis (PCA) of the polymorphic markers in fragments near the ahchi1 gene was enriched in cultivated strains, and this was caused by multiple independent instances of artificial selection. We revealed for the first time the genetic basis of the ahchi1 gene in domestication, thereby providing a foundation for elucidating the potential function of the ahchi1 gene in the breeding of A. heimuer.

RevDate: 2022-07-16

Cooper ZS, Rapp JZ, Shoemaker AMD, et al (2022)

Evolutionary Divergence of Marinobacter Strains in Cryopeg Brines as Revealed by Pangenomics.

Frontiers in microbiology, 13:879116.

Marinobacter spp. are cosmopolitan in saline environments, displaying a diverse set of metabolisms that allow them to competitively occupy these environments, some of which can be extreme in both salinity and temperature. Here, we introduce a distinct cluster of Marinobacter genomes, composed of novel isolates and in silico assembled genomes obtained from subzero, hypersaline cryopeg brines, relic seawater-derived liquid habitats within permafrost sampled near Utqiaġvik, Alaska. Using these new genomes and 45 representative publicly available genomes of Marinobacter spp. from other settings, we assembled a pangenome to examine how the new extremophile members fit evolutionarily and ecologically, based on genetic potential and environmental source. This first genus-wide genomic analysis revealed that Marinobacter spp. in general encode metabolic pathways that are thermodynamically favored at low temperature, cover a broad range of organic compounds, and optimize protein usage, e.g., the Entner-Doudoroff pathway, the glyoxylate shunt, and amino acid metabolism. The new isolates contributed to a distinct clade of subzero brine-dwelling Marinobacter spp. that diverged genotypically and phylogenetically from all other Marinobacter members. The subzero brine clade displays genomic characteristics that may explain competitive adaptations to the extreme environments they inhabit, including more abundant membrane transport systems (e.g., for organic substrates, compatible solutes, and ions) and stress-induced transcriptional regulatory mechanisms (e.g., for cold and salt stress) than in the other Marinobacter clades. We also identified more abundant signatures of potential horizontal transfer of genes involved in transcription, the mobilome, and a variety of metabolite exchange systems, which led to considering the importance of this evolutionary mechanism in an extreme environment where adaptation via vertical evolution is physiologically rate limited. Assessing these new extremophile genomes in a pangenomic context has provided a unique view into the ecological and evolutionary history of the genus Marinobacter, particularly with regard to its remarkable diversity and its opportunism in extremely cold and saline environments.

RevDate: 2022-07-16
CmpDate: 2022-06-24

Kuzmanović N, Biondi E, Overmann J, et al (2022)

Genomic analysis provides novel insights into diversification and taxonomy of Allorhizobium vitis (i.e. Agrobacterium vitis).

BMC genomics, 23(1):462.

BACKGROUND: Allorhizobium vitis (formerly named Agrobacterium vitis or Agrobacterium biovar 3) is the primary causative agent of crown gall disease of grapevine worldwide. We obtained and analyzed whole-genome sequences of diverse All. vitis strains to get insights into their diversification and taxonomy.

RESULTS: Pairwise genome comparisons and phylogenomic analysis of various All. vitis strains clearly indicated that All. vitis is not a single species, but represents a species complex composed of several genomic species. Thus, we emended the description of All. vitis, which now refers to a restricted group of strains within the All. vitis species complex (i.e. All. vitis sensu stricto) and proposed a description of a novel species, All. ampelinum sp. nov. The type strain of All. vitis sensu stricto remains the current type strain of All. vitis, K309T. The type strain of All. ampelinum sp. nov. is S4T. We also identified sets of gene clusters specific to the All. vitis species complex, All. vitis sensu stricto and All. ampelinum, respectively, for which we predicted the biological function and infer the role in ecological diversification of these clades, including some we could experimentally validate. All. vitis species complex-specific genes confer tolerance to different stresses, including exposure to aromatic compounds. Similarly, All. vitis sensu stricto-specific genes confer the ability to degrade 4-hydroxyphenylacetate and a putative compound related to gentisic acid. All. ampelinum-specific genes have putative functions related to polyamine metabolism and nickel assimilation. Congruently with the genome-based classification, All. vitis sensu stricto and All. ampelinum were clearly delineated by MALDI-TOF MS analysis. Moreover, our genome-based analysis indicated that Allorhizobium is clearly separated from other genera of the family Rhizobiaceae.

CONCLUSIONS: Comparative genomics and phylogenomic analysis provided novel insights into the diversification and taxonomy of Allorhizobium vitis species complex, supporting our redefinition of All. vitis sensu stricto and description of All. ampelinum. Our pan-genome analyses suggest that these species have differentiated ecologies, each relying on specialized nutrient consumption or toxic compound degradation to adapt to their respective niche.

RevDate: 2022-08-01
CmpDate: 2022-07-19

Romero Picazo D, Werner A, Dagan T, et al (2022)

Pangenome Evolution in Environmentally Transmitted Symbionts of Deep-Sea Mussels Is Governed by Vertical Inheritance.

Genome biology and evolution, 14(7):.

Microbial pangenomes vary across species; their size and structure are determined by genetic diversity within the population and by gene loss and horizontal gene transfer (HGT). Many bacteria are associated with eukaryotic hosts where the host colonization dynamics may impact bacterial genome evolution. Host-associated lifestyle has been recognized as a barrier to HGT in parentally transmitted bacteria. However, pangenome evolution of environmentally acquired symbionts remains understudied, often due to limitations in symbiont cultivation. Using high-resolution metagenomics, here we study pangenome evolution of two co-occurring endosymbionts inhabiting Bathymodiolus brooksi mussels from a single cold seep. The symbionts, sulfur-oxidizing (SOX) and methane-oxidizing (MOX) gamma-proteobacteria, are environmentally acquired at an early developmental stage and individual mussels may harbor multiple strains of each symbiont species. We found differences in the accessory gene content of both symbionts across individual mussels, which are reflected by differences in symbiont strain composition. Compared with core genes, accessory genes are enriched in genome plasticity functions. We found no evidence for recent HGT between both symbionts. A comparison between the symbiont pangenomes revealed that the MOX population is less diverged and contains fewer accessory genes, supporting that the MOX association with B. brooksi is more recent in comparison to that of SOX. Our results show that the pangenomes of both symbionts evolved mainly by vertical inheritance. We conclude that genome evolution of environmentally transmitted symbionts that associate with individual hosts over their lifetime is affected by a narrow symbiosis where the frequency of HGT is constrained.

RevDate: 2022-07-06
CmpDate: 2022-07-06

Da Silva WM, Larzabal M, Aburjaile FF, et al (2022)

Whole-genome sequencing analysis of Shiga toxin-producing Escherichia coli O22:H8 isolated from cattle prediction pathogenesis and colonization factors and position in STEC universe phylogeny.

Journal of microbiology (Seoul, Korea), 60(7):689-704.

Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen capable of causing illness in humans. In a previous study, our group showed that a STEC isolate belonging to O22:H8 serotype (strain 154) can interfere with STEC O157:H7 colonization both in vitro and in vivo. Using whole-genome sequencing and genomic comparative, we predicted a subset of genes acquired by O22:H8 strain 154 through horizontal gene transfer that might be responsible for the phenotype previously described by our group. Among them were identified genes related to the pathogenesis of non-LEE (locus of enterocyte effacement) STEC, specific metabolic processes, antibiotic resistance and genes encoding for the T6SS-1 that is related to inter-bacterial competition. In addition, we showed that this strain carries stx1c and stx2dact, a mucus-inducible variant. The results obtained in this study provide insights into STEC genomic plasticity and the importance of genomic islands in the adaptation and pathogenesis of this pathogen.

RevDate: 2022-07-21

Bai X, Ylinen E, Zhang J, et al (2022)

Comparative Genomics of Shiga Toxin-Producing Escherichia coli Strains Isolated from Pediatric Patients with and without Hemolytic Uremic Syndrome from 2000 to 2016 in Finland.

Microbiology spectrum [Epub ahead of print].

Shiga toxin-producing Escherichia coli (STEC) infection can cause mild to severe illness, such as nonbloody or bloody diarrhea, and the fatal hemolytic uremic syndrome (HUS). The molecular mechanism underlying the variable pathogenicity of STEC infection is not fully defined so far. Here, we performed a comparative genomics study on a large collection of clinical STEC strains collected from STEC-infected pediatric patients with and without HUS in Finland over a 16-year period, aiming to identify the bacterial genetic factors that can predict the risk to cause HUS and poor renal outcome. Of 240 STEC strains included in this study, 52 (21.7%) were from pediatric patients with HUS. Serotype O157:H7 was the main cause of HUS, and Shiga toxin gene subtype stx2a was significantly associated with HUS. Comparative genomics and pangenome-wide association studies identified a number of virulence and accessory genes overrepresented in HUS-associated STEC compared to non-HUS STEC strains, including genes encoding cytolethal distending toxins, type III secretion system effectors, adherence factors, etc. No virulence or accessory gene was significantly associated with risk factors for poor renal outcome among HUS patients assessed in this study, including need for and duration of dialysis, presence and duration of anuria, and leukocyte counts. Whole-genome phylogeny and multiple-correspondence analysis of pangenomes could not separate HUS STEC from non-HUS STEC strains, suggesting that STEC strains with diverse genetic backgrounds may independently acquire genetic elements that determine their varied pathogenicity. Our findings indicate that nonbacterial factors, i.e., characteristics of the host immunity, might affect STEC virulence and clinical outcomes. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) is a serious public health burden worldwide which causes outbreaks of gastrointestinal diseases and the fatal hemolytic uremic syndrome (HUS) characterized by the triad of mechanical hemolytic anemia, thrombocytopenia, and acute renal failure. Understanding the mechanism underlying the disease severity and patient outcome is of high importance. Using comparative genomics on a large collection of clinical STEC strains from STEC-infected patients with and without HUS, our study provides a reference of STEC genetic factors/variants that can be used as predictors of the development of HUS, which will aid risk assessment at the early stage of STEC infection. Additionally, our findings suggest that nonbacterial factors may play a primary role in the renal outcome in STEC-infected patients with HUS; further studies are needed to validate this.

RevDate: 2022-07-16
CmpDate: 2022-06-23

Rocha J, Henriques I, Gomila M, et al (2022)

Common and distinctive genomic features of Klebsiella pneumoniae thriving in the natural environment or in clinical settings.

Scientific reports, 12(1):10441.

The Klebsiella pneumoniae complex is comprised of ubiquitous bacteria that can be found in soils, plants or water, and as humans' opportunistic pathogens. This study aimed at inferring common and distinctive features in clinical and environmental K. pneumoniae. Whole genome sequences of members of the K. pneumoniae complex (including K. variicola, n = 6; and K. quasipneumoniae, n = 7), of clinical (n = 78) and environmental (n = 61) origin from 21 countries were accessed from the GenBank. These genomes were compared based on phylogeny, pangenome and selected clinically relevant traits. Phylogenetic analysis based on 2704 genes of the core genome showed close relatedness between clinical and environmental strains, in agreement with the multi-locus sequence typing. Eight out of the 62 sequence types (STs) identified, included both clinical and environmental genomes (ST11, ST14, ST15, ST37, ST45, ST147, ST348, ST437). Pangenome-wide association studies did not evidence significant differences between clinical and environmental genomes. However, the genomes of clinical isolates presented significantly more exclusive genes related to antibiotic resistance/plasmids, while the environmental isolates yielded significantly higher allelic diversity of genes related with functions such as efflux or oxidative stress. The study suggests that K. pneumoniae can circulate among the natural environment and clinical settings, probably under distinct adaptation pressures.

RevDate: 2022-08-02
CmpDate: 2022-06-23

Sollitto M, Kenny NJ, Greco S, et al (2022)

Detecting Structural Variants and Associated Gene Presence-Absence Variation Phenomena in the Genomes of Marine Organisms.

Methods in molecular biology (Clifton, N.J.), 2498:53-76.

As complete genomes become easier to attain, even from previously difficult-to-sequence species, and as genomic resequencing becomes more routine, it is becoming obvious that genomic structural variation is more widespread than originally thought and plays an important role in maintaining genetic variation in populations. Structural variants (SVs) and associated gene presence-absence variation (PAV) can be important players in local adaptation, allowing the maintenance of genetic variation and taking part in other evolutionarily relevant phenomena. While recent studies have highlighted the importance of structural variation in Mollusca, the prevalence of this phenomenon in the broader context of marine organisms remains to be fully investigated.Here, we describe a straightforward and broadly applicable method for the identification of SVs in fully assembled diploid genomes, leveraging the same reads used for assembly. We also explain a gene PAV analysis protocol, which could be broadly applied to any species with a fully sequenced reference genome available. Although the strength of these approaches have been tested and proven in marine invertebrates, which tend to have high levels of heterozygosity, possibly due to their lifestyle traits, they are also applicable to other species across the tree of life, providing a ready means to begin investigations into this potentially widespread phenomena.

RevDate: 2022-06-23
CmpDate: 2022-06-23

Kumar S, Bansal K, SK Sethi (2022)

Reclassification of Streptococcus ilei as a later heterotypic synonym of Streptococcus koreensis based on whole-genome sequence analysis.

Archives of microbiology, 204(7):408.

The genus Streptococcus, a member of family Streptococcaceae, is known for its wide range of industrial, clinical and human relevance. Among the species of genus Streptococcus two members, namely Streptococcus koreensis and Streptococcus ilei, were isolated from subgingival dental plaque and human small intestinal fluid, respectively. The 16S rRNA gene sequence similarity of the type strains of these members shows a similarity of 99.87%. In this study, we performed a systematic study to clarify the taxonomic assignment of these two species. Genome similarity assessment based on whole-genome sequence information such as average nucleotide identity using orthoANI and fastANI, digital DNA-DNA hybridization value between S. koreensis and S. ilei were 96.31, 96.60, 86.4 and 97.63, respectively. All these genome similarity values clearly exceeded the species delineation cutoffs. Phylogenetic assessment using 16S rRNA gene and whole-genome information using PhyloPhlAn, which uses around 400 conserved genes across bacterial phyla, provides additional evidence for these members forming a monophyletic clade in the phylogenetic tree. Pan genome analysis suggests a very large core genome (n = 1374) and the presence of no unique gene between the genomes of S. koreensis and S. ilei. Additionally, we found highly syntenic genomes of type strains of these two species. Based on these evidences, we propose S. ilei should be reclassified as a later heterotypic synonym of S. koreensis.

RevDate: 2022-07-21

Montelongo C, Mores CR, Putonti C, et al (2022)

Whole-Genome Sequencing of Staphylococcus aureus and Staphylococcus haemolyticus Clinical Isolates from Egypt.

Microbiology spectrum [Epub ahead of print].

Infections caused by antibiotic-resistant Staphylococcus are a global concern. This is true in the Middle East, where increasingly resistant Staphylococcus aureus and Staphylococcus haemolyticus strains have been detected. While extensive surveys have revealed the prevalence of infections caused by antibiotic-resistant staphylococci in Europe, Asia, and North America, the population structure of antibiotic-resistant staphylococci recovered from patients and clinical settings in Egypt remains uncharacterized. We performed whole-genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital; 46 of the S. aureus genomes and all 10 of the S. haemolyticus genomes carry mecA, which confers methicillin resistance. Supplemented with additional publicly available genomes from the other parts of the Middle East (34 S. aureus and 6 S. haemolyticus), we present the largest genomic study to date of staphylococcal isolates from the Middle East. These genomes include 20 S. aureus multilocus sequence types (MLST), including 3 new ones. They also include 9 S. haemolyticus MLSTs, including 1 new one. Phylogenomic analyses of each species' core genome largely mirrored those of the MLSTs, irrespective of geographical origin. The hospital-acquired spa t037/ST239-SCCmec III/MLST CC8 clone represented the largest clade, comprising 22% of the S. aureus isolates. Like S. aureus genome surveys of other regions, these isolates from the Middle East have an open pangenome, a strong indicator of gene exchange of virulence factors and antibiotic resistance genes with other reservoirs. Our genome analyses will inform antibiotic stewardship and infection control plans in the Middle East. IMPORTANCE Staphylococci are understudied despite their prevalence within the Middle East. Methicillin-resistant Staphylococcus aureus (MRSA) is endemic to hospitals in Egypt, as are other antibiotic-resistant strains of S. aureus and S. haemolyticus. To provide insight into the strains circulating in Egypt, we performed whole-genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital. Through analysis of these genomes, as well as all available S. aureus and S. haemolyticus genomes from the Middle East (n = 40), we were able to produce a picture of the diversity in this region more complete than those afforded by traditional molecular typing strategies. For example, we identified 4 new MLSTs. Most strains harbored genes associated with multidrug resistance, toxin production, biofilm formation, and immune evasion. These data provide invaluable insight for future antibiotic stewardship and infection control within the Middle East.

RevDate: 2022-07-16

Parakkunnel R, Bhojaraja Naik K, Susmita C, et al (2022)

Evolution and co-evolution: insights into the divergence of plant heat shock factor genes.

Physiology and molecular biology of plants : an international journal of functional plant biology, 28(5):1029-1047.

The Heat Shock Factor (Hsf) genes are widely distributed across the plant kingdom regulating the plant response to various abiotic stresses. In addition to natural selection, breeding and accelerated selection changed the structure and function of Hsf genes. 1076 Hsf genes from 30 genera from primitive algae to the most advanced plant species and major crop plants were used for phylogenetic analysis. The interspecific divergence was studied with 11 members of genus Oryza while intraspecific divergence was studied with sesame pan-genome adapted to diverse ecological niches. B2 genes in eudicots and monocots originated separately while A1 gave rise to the recently evolved Class-C genes and land colonization happened with evolution of A1 genes. An increase in the number of lineages in the Oryza clade with the evolution of AA genome indicated independent domestication and positive selection was observed in > 53% of loci whereas the highly conserved homologues were under purifying selection. The paralogous genes under positive selection exhibited more domain changes for diversified function and increased fitness. A significant co-evolving cluster involving amino acids Phenylalanine, Lysine and Valine played crucial role in maintaining hydrophobic core along with highly conserved Tryptophan residues. A mutation of Glutamic acid to Glutamine was observed in A8 genes of Lamiales affecting protein solvency. Breeding resulted in accumulation of mutations reducing the hydrophobicity of proteins and a further reduction in protein aggregation. This study identify genome duplications, non-neutral selection and co-evolving residues as causing drastic changes in the conserved domain of Hsf proteins.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-022-01183-7.

RevDate: 2022-07-16

Podrzaj L, Burtscher J, KJ Domig (2022)

Comparative Genomics Provides Insights Into Genetic Diversity of Clostridium tyrobutyricum and Potential Implications for Late Blowing Defects in Cheese.

Frontiers in microbiology, 13:889551.

Clostridium tyrobutyricum has been recognized as the main cause of late blowing defects (LBD) in cheese leading to considerable economic losses for the dairy industry. Although differences in spoilage ability among strains of this species have been acknowledged, potential links to the genetic diversity and functional traits remain unknown. In the present study, we aimed to investigate and characterize genomic variation, pan-genomic diversity and key traits of C. tyrobutyricum by comparing the genomes of 28 strains. A comparative genomics analysis revealed an "open" pangenome comprising 9,748 genes and a core genome of 1,179 genes shared by all test strains. Among those core genes, the majority of genes encode proteins related to translation, ribosomal structure and biogenesis, energy production and conversion, and amino acid metabolism. A large part of the accessory genome is composed of sets of unique, strain-specific genes ranging from about 5 to more than 980 genes. Furthermore, functional analysis revealed several strain-specific genes related to replication, recombination and repair, cell wall, membrane and envelope biogenesis, and defense mechanisms that might facilitate survival under stressful environmental conditions. Phylogenomic analysis divided strains into two clades: clade I contained human, mud, and silage isolates, whereas clade II comprised cheese and milk isolates. Notably, these two groups of isolates showed differences in certain hypothetical proteins, transcriptional regulators and ABC transporters involved in resistance to oxidative stress. To the best of our knowledge, this is the first study to provide comparative genomics of C. tyrobutyricum strains related to LBD. Importantly, the findings presented in this study highlight the broad genetic diversity of C. tyrobutyricum, which might help us understand the diversity in spoilage potential of C. tyrobutyricum in cheese and provide some clues for further exploring the gene modules responsible for the spoilage ability of this species.

RevDate: 2022-07-16

Wang Y, Habekuß A, Jayakodi M, et al (2022)

High-Resolution Mapping of Barley mild mosaic virus Resistance Gene rym15.

Frontiers in plant science, 13:908170.

Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), which are transmitted by the soil-borne plasmodiophorid Polymyxa graminis, cause high yield losses in barley. In previous studies, the recessive BaMMV resistance gene rym15, derived from the Japanese landrace Chikurin Ibaraki 1, was mapped on chromosome 6HS of Hordeum vulgare. In this study, 423 F4 segmental recombinant inbred lines (RILs) were developed from crosses of Chikurin Ibaraki 1 with two BaMMV-susceptible cultivars, Igri (139 RILs) and Uschi (284 RILs). A set of 32 competitive allele-specific PCR (KASP) assays, designed using single nucleotide polymorphisms (SNPs) from the barley 50 K Illumina Infinium iSelect SNP chip, genotyping by sequencing (GBS) and whole-genome sequencing (WGS), was used as a backbone for construction of two high-resolution maps. Using this approach, the target locus was narrowed down to 0.161 cM and 0.036 cM in the Igri × Chikurin Ibaraki 1 (I × C) and Chikurin Ibaraki 1 × Uschi (C × U) populations, respectively. Corresponding physical intervals of 11.3 Mbp and 0.281 Mbp were calculated for I × C and C × U, respectively, according to the Morex v3 genome sequence. In the 0.281 Mbp target region, six high confidence (HC) and two low confidence (LC) genes were identified. Genome assemblies of BaMMV-susceptible cultivars Igri and Golden Promise from the barley pan-genome, and a HiFi assembly of Chikurin Ibaraki 1 together with re-sequencing data for the six HC and two LC genes in susceptible parental cultivar Uschi revealed functional SNPs between resistant and susceptible genotypes only in two of the HC genes. These SNPs are the most promising candidates for the development of functional markers and the two genes represent promising candidates for functional analysis.

RevDate: 2022-07-12
CmpDate: 2022-07-12

Nanjani S, Soni R, Paul D, et al (2022)

Genome analysis uncovers the prolific antagonistic and plant growth-promoting potential of endophyte Bacillus velezensis K1.

Gene, 836:146671.

Insights into the application of endophytic bacilli in sustainable agricultural practices have opened up new avenues for the inhibition of soil-borne pathogens and the improvement of plant health. Bacillus subtilis K1, an endophytic bacterium originally isolated from aerial roots of Ficus benghalensis is a potential biocontrol agent secreting a mixture of surfactins, iturins and fengycins. The current study extends the characterization of this bacterium through genomic and comparative genomics approaches. The sequencing of the bacterial genome at Illumina MiSeq platform revealed that it possessed a 4,103,502-bp circular chromosome with 45.98% GC content and 4325 predicted protein-coding sequences. Based on phylogenomics and whole-genome average nucleotide identity, the B. subtilis K1 was taxonomically classified as Bacillus velezensis. The formerly evaluated phenotypic traits viz. C-source utilization and lipopeptide-mediated fungal antagonism were correlated to their molecular determinants. The genome also harbored several genes associated with induced systemic resistance and plant growth promotion i.e, phytohormone production, nitrogen assimilation and reduction, siderophore production, phosphate solubilization, biofilm formation, swarming motility, acetoin and butanediol synthesis. The production of antifungal volatile organic compounds and plant growth promotion was experimentally demonstrated by volatile compound assay and seed germination assay on cumin and groundnut. The isolate also holds great prospects for application as a soil inoculant as indicated by enhancement in the growth of groundnut via in planta pot studies. Bacterial pan-genome analysis based on a comparison of whole genomes with eighteen other Bacillus strains was also conducted. Comparative examination of biosynthetic gene clusters across all genomes indicated that the largest number of gene clusters were harbored by the K1 genome. Based on the findings, we propose K1 as a model for scrutinizing non-ribosomally synthesized peptide synthetase and polyketide synthetase derived molecules.

RevDate: 2022-07-16

Posada-Reyes AB, Balderas-Martínez YI, Ávila-Ríos S, et al (2022)

An Epistatic Network Describes oppA and glgB as Relevant Genes for Mycobacterium tuberculosis.

Frontiers in molecular biosciences, 9:856212.

Mycobacterium tuberculosis is an acid-fast bacterium that causes tuberculosis worldwide. The role of epistatic interactions among different loci of the M. tuberculosis genome under selective pressure may be crucial for understanding the disease and the molecular basis of antibiotic resistance acquisition. Here, we analyzed polymorphic loci interactions by applying a model-free method for epistasis detection, SpydrPick, on a pan-genome-wide alignment created from a set of 254 complete reference genomes. By means of the analysis of an epistatic network created with the detected epistatic interactions, we found that glgB (α-1,4-glucan branching enzyme) and oppA (oligopeptide-binding protein) are putative targets of co-selection in M. tuberculosis as they were associated in the network with M. tuberculosis genes related to virulence, pathogenesis, transport system modulators of the immune response, and antibiotic resistance. In addition, our work unveiled potential pharmacological applications for genotypic antibiotic resistance inherent to the mutations of glgB and oppA as they epistatically interact with fprA and embC, two genes recently included as antibiotic-resistant genes in the catalog of the World Health Organization. Our findings showed that this approach allows the identification of relevant epistatic interactions that may lead to a better understanding of M. tuberculosis by deciphering the complex interactions of molecules involved in its metabolism, virulence, and pathogenesis and that may be applied to different bacterial populations.

RevDate: 2022-07-25

Tantoso E, Eisenhaber B, Kirsch M, et al (2022)

To kill or to be killed: pangenome analysis of Escherichia coli strains reveals a tailocin specific for pandemic ST131.

BMC biology, 20(1):146.

BACKGROUND: Escherichia coli (E. coli) has been one of the most studied model organisms in the history of life sciences. Initially thought just to be commensal bacteria, E. coli has shown wide phenotypic diversity including pathogenic isolates with great relevance to public health. Though pangenome analysis has been attempted several times, there is no systematic functional characterization of the E. coli subgroups according to the gene profile.

RESULTS: Systematically scanning for optimal parametrization, we have built the E. coli pangenome from 1324 complete genomes. The pangenome size is estimated to be ~25,000 gene families (GFs). Whereas the core genome diminishes as more genomes are added, the softcore genome (≥95% of strains) is stable with ~3000 GFs regardless of the total number of genomes. Apparently, the softcore genome (with a 92% or 95% generation threshold) can define the genome of a bacterial species listing the critically relevant, evolutionarily most conserved or important classes of GFs. Unsupervised clustering of common E. coli sequence types using the presence/absence GF matrix reveals distinct characteristics of E. coli phylogroups B1, B2, and E. We highlight the bi-lineage nature of B1, the variation of the secretion and of the iron acquisition systems in ST11 (E), and the incorporation of a highly conserved prophage into the genome of ST131 (B2). The tail structure of the prophage is evolutionarily related to R2-pyocin (a tailocin) from Pseudomonas aeruginosa PAO1. We hypothesize that this molecular machinery is highly likely to play an important role in protecting its own colonies; thus, contributing towards the rapid rise of pandemic E. coli ST131.

CONCLUSIONS: This study has explored the optimized pangenome development in E. coli. We provide complete GF lists and the pangenome matrix as supplementary data for further studies. We identified biological characteristics of different E. coli subtypes, specifically for phylogroups B1, B2, and E. We found an operon-like genome region coding for a tailocin specific for ST131 strains. The latter is a potential killer weapon providing pandemic E. coli ST131 with an advantage in inter-bacterial competition and, suggestively, explains their dominance as human pathogen among E. coli strains.

RevDate: 2022-06-15

Kong X, Wang H, Guo G, et al (2022)

Duck sewage source coliphage P762 can lyse STEC and APEC.

Virus genes [Epub ahead of print].

Multiple pathogenic types or serotypes restrict treatment for colibacillosis. In addition, rising antibiotic resistance has heightened public awareness to prevent and control pathogenic Escherichia coli. The bacteriophage is a viable technique to treat colibacillosis as an alternative to antibiotics. P762, a coliphage isolated from duck farm sewage, was demonstrated to cloud lyse Shiga toxin-producing Escherichia Coli serotypes O157 and non-O157 (17/39), Avian pathogenic E. coli covered serotype O78, O83, and O9 (5/19), and other pathogenic Escherichia coli (5/17). Additional fundamental biological characteristics analysis revealed that P762 is stable at pH 3 ~ 11 and temperature between 4 °C and 60 °C, and its optimum multiplicity of infection (MOI) is 0.1. The one-step curve of P762 exhibited three bursts of growth stage: two rapid and one slow stage. Furthermore, the first rapid burst size is 80 CFU/PFU, the burst size of the slow stage is 10 CFU/PFU, and the second rapid burst size is about 990 CFU/PFU. In addition, P762 can form a "halo" on a double agar plate, implying that the phage secretes depolymerase. With 95.14% identity and 90% query coverage, genome sequence analysis revealed that P762 is most closely related to Escherichia phage DY1, which belongs to the genus Kayfunavirus. After screening using RAST and VFDB, no virulence factors were discovered in P762. In vitro antibacterial tests revealed that P762 has high bactericidal activity in lettuce leaves contaminated with STEC. In conclusion, phage P762 might be employed in the future to prevent and control pathogenic Escherichia coli.

RevDate: 2022-07-06

De Oliveira AL, Srivastava A, Espada-Hinojosa S, et al (2022)

The complete and closed genome of the facultative generalist Candidatus Endoriftia persephone from deep-sea hydrothermal vents.

Molecular ecology resources [Epub ahead of print].

The mutualistic interactions between Riftia pachyptila and its endosymbiont Candidatus Endoriftia persephone (short Endoriftia) have been extensively researched. However, the closed Endoriftia genome is still lacking. Here, by employing single-molecule real-time sequencing we present the closed chromosomal sequence of Endoriftia. In contrast to theoretical predictions of enlarged and mobile genetic element-rich genomes related to facultative endosymbionts, the closed Endoriftia genome is streamlined with fewer than expected coding sequence regions, insertion-, prophage-sequences and transposase-coding sequences. Automated and manually curated functional analyses indicated that Endoriftia is more versatile regarding sulphur metabolism than previously reported. We identified the presence of two identical rRNA operons and two long CRISPR regions in the closed genome. Additionally, pangenome analyses revealed the presence of three types of secretion systems (II, IV and VI) in the different Endoriftia populations indicating lineage-specific adaptations. The in depth mobilome characterization identified the presence of shared genomic islands in the different Endoriftia drafts and in the closed genome, suggesting that the acquisition of foreign DNA predates the geographical dispersal of the different endosymbiont populations. Finally, we found no evidence of epigenetic regulation in Endoriftia, as revealed by gene screenings and absence of methylated modified base motifs in the genome. As a matter of fact, the restriction-modification system seems to be dysfunctional in Endoriftia, pointing to a higher importance of molecular memory-based immunity against phages via spacer incorporation into CRISPR system. The Endoriftia genome is the first closed tubeworm endosymbiont to date and will be valuable for future gene oriented and evolutionary comparative studies.

RevDate: 2022-07-16

Mustapha MM, Srinivasa VR, Griffith MP, et al (2022)

Genomic Diversity of Hospital-Acquired Infections Revealed through Prospective Whole-Genome Sequencing-Based Surveillance.

mSystems, 7(3):e0138421.

Healthcare-associated infections (HAIs) cause mortality, morbidity, and waste of health care resources. HAIs are also an important driver of antimicrobial resistance, which is increasing around the world. Beginning in November 2016, we instituted an initiative to detect outbreaks of HAIs using prospective whole-genome sequencing-based surveillance of bacterial pathogens collected from hospitalized patients. Here, we describe the diversity of bacteria sampled from hospitalized patients at a single center, as revealed through systematic analysis of bacterial isolate genomes. We sequenced the genomes of 3,004 bacterial isolates from hospitalized patients collected over a 25-month period. We identified bacteria belonging to 97 distinct species, which were distributed among 14 groups of related species. Within these groups, isolates could be distinguished from one another by both average nucleotide identity (ANI) and principal-component analysis of accessory genes (PCA-A). Core genome genetic distances and rates of evolution varied among species, which has practical implications for defining shared ancestry during outbreaks and for our broader understanding of the origins of bacterial strains and species. Finally, antimicrobial resistance genes and putative mobile genetic elements were frequently observed, and our systematic analysis revealed patterns of occurrence across the different species sampled from our hospital. Overall, this study shows how understanding the population structure of diverse pathogens circulating in a single health care setting can improve the discriminatory power of genomic epidemiology studies and can help define the processes leading to strain and species differentiation. IMPORTANCE Hospitalized patients are at increased risk of becoming infected with antibiotic-resistant organisms. We used whole-genome sequencing to survey and compare over 3,000 clinical bacterial isolates collected from hospitalized patients at a large medical center over a 2-year period. We identified nearly 100 different bacterial species, which we divided into 14 different groups of related species. When we examined how genetic relatedness differed between species, we found that different species were likely evolving at different rates within our hospital. This is significant because the identification of bacterial outbreaks in the hospital currently relies on genetic similarity cutoffs, which are often applied uniformly across organisms. Finally, we found that antibiotic resistance genes and mobile genetic elements were abundant and were shared among the bacterial isolates we sampled. Overall, this study provides an in-depth view of the genomic diversity and evolutionary processes of bacteria sampled from hospitalized patients, as well as genetic similarity estimates that can inform hospital outbreak detection and prevention efforts.

RevDate: 2022-07-16

Hwang Y, PR Girguis (2022)

Differentiated Evolutionary Strategies of Genetic Diversification in Atlantic and Pacific Thaumarchaeal Populations.

mSystems, 7(3):e0147721.

Some marine microbes are seemingly "ubiquitous," thriving across a wide range of environmental conditions. While the increased depth in metagenomic sequencing has led to a growing body of research on within-population heterogeneity in environmental microbial populations, there have been fewer systematic comparisons and characterizations of population-level genetic diversity over broader expanses of time and space. Here, we investigated the factors that govern the diversification of ubiquitous microbial taxa found within and between ocean basins. Specifically, we use mapped metagenomic paired reads to examine the genetic diversity of ammonia-oxidizing archaeal ("Candidatus Nitrosopelagicus brevis") populations in the Pacific (Hawaii Ocean Time-series [HOT]) and Atlantic (Bermuda Atlantic Time Series [BATS]) Oceans sampled over 2 years. We observed higher nucleotide diversity in "Ca. N. brevis" at HOT, driven by a higher rate of homologous recombination. In contrast, "Ca. N. brevis" at BATS featured a more open pangenome with a larger set of genes that were specific to BATS, suggesting a history of dynamic gene gain and loss events. Furthermore, we identified highly differentiated genes that were regulatory in function, some of which exhibited evidence of recent selective sweeps. These findings indicate that different modes of genetic diversification likely incur specific adaptive advantages depending on the selective pressures that they are under. Within-population diversity generated by the environment-specific strategies of genetic diversification is likely key to the ecological success of "Ca. N. brevis." IMPORTANCE Ammonia-oxidizing archaea (AOA) are one of the most abundant chemolithoautotrophic microbes in the marine water column and are major contributors to global carbon and nitrogen cycling. Despite their ecological importance and geographical pervasiveness, there have been limited systematic comparisons and characterizations of their population-level genetic diversity over time and space. Here, we use metagenomic time series from two ocean observatories to address the fundamental questions of how abiotic and biotic factors shape the population-level genetic diversity and how natural microbial populations adapt across diverse habitats. We show that the marine AOA "Candidatus Nitrosopelagicus brevis" in different ocean basins exhibits distinct modes of genetic diversification in response to their selective regimes shaped by nutrient availability and patterns of environmental fluctuations. Our findings specific to "Ca. N. brevis" have broader implications, particularly in understanding the population-level responses to the changing climate and predicting its impact on biogeochemical cycles.

RevDate: 2022-06-14
CmpDate: 2022-06-14

Palma F, Radomski N, Guérin A, et al (2022)

Genomic elements located in the accessory repertoire drive the adaptation to biocides in Listeria monocytogenes strains from different ecological niches.

Food microbiology, 106:103757.

In response to the massive use of biocides for controlling Listeria monocytogenes (hereafter Lm) contaminations along the food chain, strains showing biocide tolerance emerged. Here, accessory genomic elements were associated with biocide tolerance through pangenome-wide associations performed on 197 Lm strains from different lineages, ecological, geographical and temporal origins. Mobile elements, including prophage-related loci, the Tn6188_qacH transposon and pLMST6_emrC plasmid, were widespread across lineage I and II food strains and associated with tolerance to benzalkonium-chloride (BC), a quaternary ammonium compound (QAC) widely used in food processing. The pLMST6_emrC was also associated with tolerance to another QAC, the didecyldimethylammonium-chloride, displaying a pleiotropic effect. While no associations were detected for chemically reactive biocides (alcohols and chlorines), genes encoding for cell-surface proteins were associated with BC or polymeric biguanide tolerance. The latter was restricted to lineage I strains from animal and the environment. In conclusion, different genetic markers, with polygenic nature or not, appear to have driven the Lm adaptation to biocide, especially in food strains but also from animal and the environment. These markers could aid to monitor and predict the spread of biocide tolerant Lm genotypes across different ecological niches, finally reducing the risk of such strains in food industrial settings.

RevDate: 2022-07-16

Quan C, Lu H, Lu Y, et al (2022)

Population-scale genotyping of structural variation in the era of long-read sequencing.

Computational and structural biotechnology journal, 20:2639-2647.

Population-scale studies of structural variation (SV) are growing rapidly worldwide with the development of long-read sequencing technology, yielding a considerable number of novel SVs and complete gap-closed genome assemblies. Herein, we highlight recent studies using a hybrid sequencing strategy and present the challenges toward large-scale genotyping for SVs due to the reference bias. Genotyping SVs at a population scale remains challenging, which severely impacts genotype-based population genetic studies or genome-wide association studies of complex diseases. We summarize academic efforts to improve genotype quality through linear or graph representations of reference and alternative alleles. Graph-based genotypers capable of integrating diverse genetic information are effectively applied to large and diverse cohorts, contributing to unbiased downstream analysis. Meanwhile, there is still an urgent need in this field for efficient tools to construct complex graphs and perform sequence-to-graph alignments.

RevDate: 2022-07-16
CmpDate: 2022-06-13

Lin G, Liu Q, Wang L, et al (2022)

The Comparative Analysis of Genomic Diversity and Genes Involved in Carbohydrate Metabolism of Eighty-Eight Bifidobacterium pseudocatenulatum Isolates from Different Niches of China.

Nutrients, 14(11):.

Eighty-eight Bifidobacterium pseudocatenulatum strains, which were isolated from human, chicken and cow fecal samples from different niches of China, were compared genomically in this study to evaluate their diversity. It was found that B. pseudocatenulatum displayed a closed pan-genome, including abundant glycoside hydrolase families of the carbohydrate active enzyme (CAZy). A total of 30 kinds of glycoside hydrolases (GHs), 14 kinds of glycosyl transferases (GTs), 13 kinds of carbohydrate-binding modules (CBMs), 6 kinds of carbohydrate-esterases (CEs), and 2 kinds of auxiliary activities (AAs) gene families were identified across the genomes of the 88 B. pseudocatenulatum strains. Specifically, this showed that significant differences were also present in the number of 10 carbohydrate-active enzyme gene families (GT51, GH13_32, GH26, GH42, GH121, GH3, AA3, CBM46, CE2, and CE6) among the strains derived from the hosts of different age groups, particularly between strains from infants and those from other human age groups. Twelve different individuals of B. pseudocatenulatum from four main clusters were selected for further study to reveal the genetic diversity of carbohydrate metabolism-related genes within the same phylogenetics. The animal experiment showed that 3 weeks of oral administration and 1 week after cessation of administration of these strains did not markedly alter the serum routine inflammatory indicators in mice. Furthermore, the administration of these strains did not significantly cause adverse changes in the gut microbiota, as indicated by the α- and β-diversity indexes, relative to the control group (normal diet). Beyond that, FAHBZ9L5 significantly increased the abundance of B. pseudocatenulatum after 3 weeks and significantly increased the abundance of acetic acid and butyric acid in the host's intestinal tract 3 and 4 weeks after the first administration, respectively, compared with the control group. Corresponding to this, comparative genomic analyses of 12 B. pseudocatenulatum suggest that FAHBZ9L5-specific genes were rich in ABC transporters and carbohydrate esterase. Combining the results of comparative genomics analyses and animal experiment, it is suggested that the strains containing certain gene clusters contribute to another competitive growth advantage of B. pseudocatenulatum, which facilitates its intestinal carbohydrate metabolism in a host.

RevDate: 2022-07-29
CmpDate: 2022-06-17

Zhou Y, Zhang Z, Bao Z, et al (2022)

Graph pangenome captures missing heritability and empowers tomato breeding.

Nature, 606(7914):527-534.

Missing heritability in genome-wide association studies defines a major problem in genetic analyses of complex biological traits1,2. The solution to this problem is to identify all causal genetic variants and to measure their individual contributions3,4. Here we report a graph pangenome of tomato constructed by precisely cataloguing more than 19 million variants from 838 genomes, including 32 new reference-level genome assemblies. This graph pangenome was used for genome-wide association study analyses and heritability estimation of 20,323 gene-expression and metabolite traits. The average estimated trait heritability is 0.41 compared with 0.33 when using the single linear reference genome. This 24% increase in estimated heritability is largely due to resolving incomplete linkage disequilibrium through the inclusion of additional causal structural variants identified using the graph pangenome. Moreover, by resolving allelic and locus heterogeneity, structural variants improve the power to identify genetic factors underlying agronomically important traits leading to, for example, the identification of two new genes potentially contributing to soluble solid content. The newly identified structural variants will facilitate genetic improvement of tomato through both marker-assisted selection and genomic selection. Our study advances the understanding of the heritability of complex traits and demonstrates the power of the graph pangenome in crop breeding.

RevDate: 2022-06-17
CmpDate: 2022-06-17

Kim E, Yang SM, Kim IS, et al (2022)

Identification of novel molecular targets for Weissella species-specific real-time PCR based on pangenome analysis.

Applied microbiology and biotechnology, 106(11):4157-4168.

Some Weissella species are used in probiotic products because of their beneficial effects in humans, whereas some species are considered as opportunistic pathogens that cause infections in humans. Therefore, an accurate and rapid identification of Weissella species is essential to control pathogenic Weissella species or isolate new functional strains with probiotic effects from their habitat. The objective of our study was to extract novel molecular targets using pangenome analysis for the identification of major Weissella species present in food. With 50 genomes representing 11 Weissella species, novel molecular targets were mined based on their 100% presence in the respective strains of the target species and absence in the strains of non-target bacteria. Primers based on molecular targets showed positive results for the corresponding species, whereas 79 non-target strains showed negative results. Standard curves revealed good linearity in the range of 103-108 colony-forming units per reaction. Our method was successfully applied to 74 Weissella strains isolated from food samples to demonstrate that the molecular targets provided a viable alternative to the 16S rRNA sequence. Furthermore, it was possible to identify and quantify Weissella communities in fermented foods. These results demonstrate that our method can be used for effective and accurate screening for the presence of Weissella species in foods. KEY POINTS: • This is first study to mine novel targets for differentiating 11 Weissella species. • The novel targets showed higher resolution than the 16S rRNA gene sequence. • The PCR method effectively detected Weissella species with opposing properties.

RevDate: 2022-07-16

Sun Y, Zhang PT, Kou DR, et al (2022)

Terpene Synthases in Rice Pan-Genome and Their Responses to Chilo suppressalis Larvae Infesting.

Frontiers in plant science, 13:905982.

Terpene synthase (TPS) catalyzes the synthesis of terpenes and plays an important role in plant defense. This study identified 45 OsTPS genes (32 core genes and 13 variable genes) based on the high-quality rice gene-based pan-genome. This indicates limitations in OsTPS gene studies based on a single reference genome. In the present study, through collinearity between multiple rice genomes, one OsTPS gene absent in the reference (Nipponbare) genome was found and two TPS genes in the reference genome were found to have atypical structures, which would have been ignored in single genome analysis. OsTPS genes were divided into five groups and TPS-b was lost according to the phylogenetic tree. OsTPSs in TPS-c and TPS-g were all core genes indicating these two groups were stable during domestication. In addition, through the analysis of transcriptome data, some structural variations were found to affect the expression of OsTPS genes. Through the Ka/Ks calculation of OsTPS genes, we found that different OsTPS genes were under different selection pressure during domestication; for example, OsTPS22 and OsTPS29 experienced stronger positive selection than the other OsTPS genes. After Chilo suppressalis larvae infesting, 25 differentially expressed OsTPS genes were identified, which are involved in the diterpene phytoalexins precursors biosynthesis and ent-kaurene biosynthesis pathways. Overall, the present study conducted a bioinformatics analysis of OsTPS genes using a high-quality rice pan-genome, which provided a basis for further study of OsTPS genes.

RevDate: 2022-07-16

Orlando F, Romanel A, Trujillo B, et al (2022)

Allele-informed copy number evaluation of plasma DNA samples from metastatic prostate cancer patients: the PCF_SELECT consortium assay.

NAR cancer, 4(2):zcac016.

Sequencing of cell-free DNA (cfDNA) in cancer patients' plasma offers a minimally-invasive solution to detect tumor cell genomic alterations to aid real-time clinical decision-making. The reliability of copy number detection decreases at lower cfDNA tumor fractions, limiting utility at earlier stages of the disease. To test a novel strategy for detection of allelic imbalance, we developed a prostate cancer bespoke assay, PCF_SELECT, that includes an innovative sequencing panel covering ∼25 000 high minor allele frequency SNPs and tailored analytical solutions to enable allele-informed evaluation. First, we assessed it on plasma samples from 50 advanced prostate cancer patients. We then confirmed improved detection of genomic alterations in samples with <10% tumor fractions when compared against an independent assay. Finally, we applied PCF_SELECT to serial plasma samples intensively collected from three patients previously characterized as harboring alterations involving DNA repair genes and consequently offered PARP inhibition. We identified more extensive pan-genome allelic imbalance than previously recognized in prostate cancer. We confirmed high sensitivity detection of BRCA2 allelic imbalance with decreasing tumor fractions resultant from treatment and identified complex ATM genomic states that may be incongruent with protein losses. Overall, we present a framework for sensitive detection of allele-specific copy number changes in cfDNA.

RevDate: 2022-07-16

Yero D, Jia B, F Gao (2022)

Editorial: Insights in Evolutionary and Genomic Microbiology: 2021.

Frontiers in microbiology, 13:915593.

RevDate: 2022-07-16

Surachat K, Kantachote D, Wonglapsuwan M, et al (2022)

Complete Genome Sequence of Weissella cibaria NH9449 and Comprehensive Comparative-Genomic Analysis: Genomic Diversity and Versatility Trait Revealed.

Frontiers in microbiology, 13:826683.

Lactic acid bacteria (LAB) in the genus Weissella spp. contain traits in their genome that confer versatility. In particular, Weissella cibaria encodes several beneficial genes that are useful in biotechnological applications. The complete genome of W. cibaria NH9449 was sequenced and an in silico comparative analysis was performed to gain insight into the genomic diversity among members of the genus Weissella. A total of 219 Weissella genomes were used in a bioinformatics analysis of pan-genomes, phylogenetics, self-defense mechanisms, virulence factors, antimicrobial resistance, and carbohydrate-active enzymes. These investigations showed that the strain NH9449 encodes several restriction-modification-related genes and a CRISPR-Cas region in its genome. The identification of carbohydrate-active enzyme-encoding genes indicated that this strain could be beneficial in biotechnological applications. The comparative genomic analysis reveals the very high genomic diversity in this genus, and some marked differences in genetic variation and genes among Weissella species. The calculated average amino acid identity (AAI) and phylogenetic analysis of core and accessory genes shows the possible existence of three new species in this genus. These new genomic insights into Weissella species and their biological functions could be useful in the food industry and other applications.

RevDate: 2022-07-16

Schulz T, Wittler R, J Stoye (2022)

Sequence-based pangenomic core detection.

iScience, 25(6):104413.

One of the most basic kinds of analysis to be performed on a pangenome is the detection of its core, i.e., the information shared among all members. Pangenomic core detection is classically done on the gene level and many tools focus exclusively on core detection in prokaryotes. Here, we present a new method for sequence-based pangenomic core detection. Our model generalizes from a strict core definition allowing us to flexibly determine suitable core properties depending on the research question and the dataset under consideration. We propose an algorithm based on a colored de Bruijn graph that runs in linear time with respect to the number of k-mers in the graph. An implementation of our method is called Corer. Because of the usage of a colored de Bruijn graph, it works alignment-free, is provided with a small memory footprint, and accepts as input assembled genomes as well as sequencing reads.

RevDate: 2022-06-21
CmpDate: 2022-06-21

Carvalho GG, Calarga AP, Zorgi NE, et al (2022)

Virulence and DNA sequence analysis of Cronobacter spp. isolated from infant cereals.

International journal of food microbiology, 376:109745.

Cronobacter spp. is an opportunistic pathogen that causes severe infections, affecting newborns and infants, and is also an emerging cause of hospital-acquired infection in elderly populations. These infections are mainly associated with the consumption of infant formulas, even though these bacteria have been isolated from other foods as well. Cronobacter spp. invades epithelial cells and escapes the immune response mechanisms, multiplying inside macrophages. However, the pathogenesis and virulence factors of these bacteria have not been fully elucidated and need to be further studied. Therefore, this study aimed to evaluate the ability of Cronobacter spp. strains isolated from infant cereals to invade and survive within macrophages, investigate the virulence phenotype using the Galleria mellonella model, and identify possible genes involved in bacterial pathogenesis through pan-genome analysis. All the isolates were able to invade macrophages and the survival of bacteria decreased over a 72 h period, with bacterial cell counts reaching up to 106 CFU/ml. Cronobacter sakazakii isolate 112 exhibited a similar mortality rate (40-70%) to the ATCC BAA 894 strain (Cronobacter sakazakii) in G. mellonella assay. In addition, some unique virulence genes (isolate 7, ada_2, tcmA_1, acrB_3; isolate 78, ampC_2, rihC_1 and isolate 112, fimH, ylpA, gtrA) were identified within isolates with the invasive profile in the in vivo and in vitro assays. Furthermore, isolates from different species were grouped into seven distinct clusters in the pan-genome analysis. The most virulent isolates (7, 78, and 112) were grouped in distinct subclusters in the cladogram. This work revealed potential Cronobacter spp. pathogenic strains recovered from infant cereals.

RevDate: 2022-07-29
CmpDate: 2022-07-29

Boatwright JL, Sapkota S, Jin H, et al (2022)

Sorghum Association Panel whole-genome sequencing establishes cornerstone resource for dissecting genomic diversity.

The Plant journal : for cell and molecular biology, 111(3):888-904.

Association mapping panels represent foundational resources for understanding the genetic basis of phenotypic diversity and serve to advance plant breeding by exploring genetic variation across diverse accessions. We report the whole-genome sequencing (WGS) of 400 sorghum (Sorghum bicolor (L.) Moench) accessions from the Sorghum Association Panel (SAP) at an average coverage of 38× (25-72×), enabling the development of a high-density genomic marker set of 43 983 694 variants including single-nucleotide polymorphisms (approximately 38 million), insertions/deletions (indels) (approximately 5 million), and copy number variants (CNVs) (approximately 170 000). We observe slightly more deletions among indels and a much higher prevalence of deletions among CNVs compared to insertions. This new marker set enabled the identification of several novel putative genomic associations for plant height and tannin content, which were not identified when using previous lower-density marker sets. WGS identified and scored variants in 5-kb bins where available genotyping-by-sequencing (GBS) data captured no variants, with half of all bins in the genome falling into this category. The predictive ability of genomic best unbiased linear predictor (GBLUP) models was increased by an average of 30% by using WGS markers rather than GBS markers. We identified 18 selection peaks across subpopulations that formed due to evolutionary divergence during domestication, and we found six Fst peaks resulting from comparisons between converted lines and breeding lines within the SAP that were distinct from the peaks associated with historic selection. This population has served and continues to serve as a significant public resource for sorghum research and demonstrates the value of improving upon existing genomic resources.

RevDate: 2022-07-16

Mohite OS, Lloyd CJ, Monk JM, et al (2022)

Pangenome analysis of Enterobacteria reveals richness of secondary metabolite gene clusters and their associated gene sets.

Synthetic and systems biotechnology, 7(3):900-910.

In silico genome mining provides easy access to secondary metabolite biosynthetic gene clusters (BGCs) encoding the biosynthesis of many bioactive compounds, which are the basis for many important drugs used in human medicine. However, the association between BGCs and other functions encoded in the genomes of producers have remained elusive. Here, we present a systems biology workflow that integrates genome mining with a detailed pangenome analysis for detecting genes associated with a particular BGC. We analyzed 3,889 enterobacterial genomes and found 13,266 BGCs, represented by 252 distinct BGC families and 347 additional singletons. A pangenome analysis revealed 88 genes putatively associated with a specific BGC coding for the colon cancer-related colibactin that code for diverse metabolic and regulatory functions. The presented workflow opens up the possibility to discover novel secondary metabolites, better understand their physiological roles, and provides a guide to identify and analyze BGC associated gene sets.

RevDate: 2022-06-01

Bayer PE, Petereit J, Durant É, et al (2022)

Wheat Panache: A pangenome graph database representing presence-absence variation across sixteen bread wheat genomes.

The plant genome [Epub ahead of print].

Bread wheat (Triticum aestivum L.) is one of humanity's most important staple crops, characterized by a large and complex genome with a high level of gene presence-absence variation (PAV) between cultivars, hampering genomic approaches for crop improvement. With the growing global population and the increasing impact of climate change on crop yield, there is an urgent need to apply genomic approaches to accelerate wheat breeding. With recent advances in DNA sequencing technology, a growing number of high-quality reference genomes are becoming available, reflecting the genetic content of a diverse range of cultivars. However, information on the presence or absence of genomic regions has been hard to visualize and interrogate because of the size of these genomes and the lack of suitable bioinformatics tools. To address this limitation, we have produced a wheat pangenome graph maintained within an online database to facilitate interrogation and comparison of wheat cultivar genomes. The database allows users to visualize regions of the pangenome to assess PAV between bread wheat genomes.

RevDate: 2022-07-16

Leonard AS, Crysnanto D, Fang ZH, et al (2022)

Structural variant-based pangenome construction has low sensitivity to variability of haplotype-resolved bovine assemblies.

Nature communications, 13(1):3012.

Advantages of pangenomes over linear reference assemblies for genome research have recently been established. However, potential effects of sequence platform and assembly approach, or of combining assemblies created by different approaches, on pangenome construction have not been investigated. Here we generate haplotype-resolved assemblies from the offspring of three bovine trios representing increasing levels of heterozygosity that each demonstrate a substantial improvement in contiguity, completeness, and accuracy over the current Bos taurus reference genome. Diploid coverage as low as 20x for HiFi or 60x for ONT is sufficient to produce two haplotype-resolved assemblies meeting standards set by the Vertebrate Genomes Project. Structural variant-based pangenomes created from the haplotype-resolved assemblies demonstrate significant consensus regardless of sequence platform, assembler algorithm, or coverage. Inspecting pangenome topologies identifies 90 thousand structural variants including 931 overlapping with coding sequences; this approach reveals variants affecting QRICH2, PRDM9, HSPA1A, TAS2R46, and GC that have potential to affect phenotype.

RevDate: 2022-07-21
CmpDate: 2022-07-19

Garrison E, Kronenberg ZN, Dawson ET, et al (2022)

A spectrum of free software tools for processing the VCF variant call format: vcflib, bio-vcf, cyvcf2, hts-nim and slivar.

PLoS computational biology, 18(5):e1009123.

Since its introduction in 2011 the variant call format (VCF) has been widely adopted for processing DNA and RNA variants in practically all population studies-as well as in somatic and germline mutation studies. The VCF format can represent single nucleotide variants, multi-nucleotide variants, insertions and deletions, and simple structural variants called and anchored against a reference genome. Here we present a spectrum of over 125 useful, complimentary free and open source software tools and libraries, we wrote and made available through the multiple vcflib, bio-vcf, cyvcf2, hts-nim and slivar projects. These tools are applied for comparison, filtering, normalisation, smoothing and annotation of VCF, as well as output of statistics, visualisation, and transformations of files variants. These tools run everyday in critical biomedical pipelines and countless shell scripts. Our tools are part of the wider bioinformatics ecosystem and we highlight best practices. We shortly discuss the design of VCF, lessons learnt, and how we can address more complex variation through pangenome graph formats, variation that can not easily be represented by the VCF format.

RevDate: 2022-07-19

Koide S, Nagano Y, Takizawa S, et al (2022)

Genomic Traits Associated with Virulence and Antimicrobial Resistance of Invasive Group B Streptococcus Isolates with Reduced Penicillin Susceptibility from Elderly Adults.

Microbiology spectrum, 10(3):e0056822.

This study aimed to investigate genomic traits underlying the antimicrobial resistance and virulence of multidrug-resistant (MDR) group B streptococci with reduced penicillin susceptibility (PRGBS) recovered from elderly patients with bloodstream infections, which remain poorly characterized. The pangenome was found to be open, with the predicted pan- and core genome sizes being 3,531 and 1,694 genes, respectively. Accessory and unique genes were enriched for the Clusters of Orthologous Groups (COG) categories L, Replication, recombination, and repair, and K, Transcription. All MDR PRGBS isolates retained a core virulence gene repertoire (bibA, fbsA/-B/-C, cspA, cfb, hylB, scpB, lmb, and the cyl operon), supporting an invasive ability similar to that of the other invasive GBS, penicillin-susceptible GBS (PSGBS), and noninvasive PRGBS isolates. The putative sequence type 1 (ST1)-specific AlpST-1 virulence gene was also retained among the serotype Ia/ST1 PRGBS isolates. In addition to tet(M) and erm(B), mef(A)-msr(D) elements or the high-level gentamicin resistance gene aac(6')-aph(2″), which are both rare in PSGBS, were detected among those MDR PRGBS isolates. In the core single-nucleotide polymorphism (SNP) phylogenetic tree, all invasive ST1 PRGBS isolates with serotypes Ia and III were placed together in a clade with a recombination rate of 3.97, which was 36 times higher than the value found for a clade formed by serotype V/ST1 PSGBS isolates derived mostly from human blood. ST1 has been the predominant sequence type among the PRGBS isolates in Japan, and serotypes Ia and III have been very rare among the ST1 PSGBS isolates. Thus, these lineages that mostly consisted of serotypes Ia/ST1 and III/ST1 PRGBS could possibly emerge through recombination within the ST1 populations. IMPORTANCE Streptococcus agalactiae, or group B Streptococcus (GBS), is recognized as the leading cause of neonatal invasive infections. However, an increasing incidence of invasive GBS infections among nonpregnant adults, particularly the elderly and those with underlying diseases, has been observed. There is a trend toward the increasing occurrence of penicillin nonsusceptibility among GBS clinical isolates, from 4.8% in 2008 to 5.8% in 2020 in Japan. Also, in the United States, the frequency of adult invasive GBS isolates suggestive of β-lactam nonsusceptibility increased from 0.7% in 2015 to 1.0% in 2016. In adults, mortality has been significantly higher among patients with bacteremia than among those without bacteremia. Our study revealed that invasive GBS with reduced penicillin susceptibility (PRGBS) isolates harbor major virulence and resistance genes known among GBS, highlighting the need for large population-based genomic surveillance studies to better understand the clinical relevance of invasive PRGBS isolates.

RevDate: 2022-07-23

Shambhu S, Cella E, Jubair M, et al (2022)

Complete Genome Sequences of Nine Streptococcus pneumoniae Serotype 3 Clonal Complex 180 Strains.

Microbiology resource announcements, 11(7):e0027522.

We announce the complete genomes of nine Streptococcus pneumoniae strains belonging to serotype 3 clonal complex 180 (CC180). The genomes consist of a single circularized contig with an average length of 2.033 Mbp. Pangenome analysis identified 1,762 core genes and 412 accessory genes. These genomes are the basis for future population genomic studies.

RevDate: 2022-07-16

Attar R, Alatawi EA, Aba Alkhayl FF, et al (2022)

Immunoinformatics and Biophysics Approaches to Design a Novel Multi-Epitopes Vaccine Design against Staphylococcus auricularis.

Vaccines, 10(5):.

Due to the misuse of antibiotics in our daily lives, antimicrobial resistance (AMR) has become a major health problem. Penicillin, the first antibiotic, was used in the 1930s and led to the emergence of AMR. Due to alterations in the microbe's genome and the evolution of new resistance mechanisms, antibiotics are losing efficacy against microbes. There are high rates of mortality and morbidity due to antibiotic resistance, so addressing this major health issue requires new approaches. Staphylococcus auricularis is a Gram-positive cocci and is capable of causing opportunistic infections and sepsis. S. auricularis is resistant to several antibiotics and does not currently have a licensed vaccine. In this study, we used bacterial pan-genome analysis (BPGA) to study S. auricularis pan-genome and applied a reverse immunology approach to prioritize vaccine targets against S. auricularis. A total of 15,444 core proteins were identified by BPGA analysis, which were then used to identify good vaccine candidates considering potential vaccine filters. Two vaccine candidates were evaluated for epitope prediction including the superoxide dismutase and gamma-glutamyl transferase protein. The epitope prediction phase involved the prediction of a variety of B-Cell and T-cell epitopes, and the epitopes that met certain criteria, such as antigenicity, immunogenicity, non-allergenicity, and non-toxicity were chosen. A multi-epitopes vaccine construct was then constructed from all the predicted epitopes, and a cholera toxin B-subunit adjuvant was also added to increase vaccine antigenicity. Three-dimensional models of the vaccine were used for downward analyses. Using the best-modeled structure, binding potency was tested with MHC-I, MHC-II and TLR-4 immune cells receptors, proving that the vaccine binds strongly with the receptors. Further, molecular dynamics simulations interpreted strong intermolecular binding between the vaccine and receptors and confirmed the vaccine epitopes exposed to the host immune system. The results support that the vaccine candidate may be capable of eliciting a protective immune response against S. auricularis and may be a promising candidate for experimental in vitro and in vivo studies.

RevDate: 2022-07-16

Uceda-Campos G, Feitosa-Junior OR, Santiago CRN, et al (2022)

Comparative Genomics of Xylella fastidiosa Explores Candidate Host-Specificity Determinants and Expands the Known Repertoire of Mobile Genetic Elements and Immunity Systems.

Microorganisms, 10(5):.

Xylella fastidiosa causes diseases in many plant species. Originally confined to the Americas, infecting mainly grapevine, citrus, and coffee, X. fastidiosa has spread to several plant species in Europe causing devastating diseases. Many pathogenicity and virulence factors have been identified, which enable the various X. fastidiosa strains to successfully colonize the xylem tissue and cause disease in specific plant hosts, but the mechanisms by which this happens have not been fully elucidated. Here we present thorough comparative analyses of 94 whole-genome sequences of X. fastidiosa strains from diverse plant hosts and geographic regions. Core-genome phylogeny revealed clades with members sharing mostly a geographic region rather than a host plant of origin. Phylogenetic trees for 1605 orthologous CDSs were explored for potential candidates related to host specificity using a score of mapping metrics. However, no candidate host-specificity determinants were strongly supported using this approach. We also show that X. fastidiosa accessory genome is represented by an abundant and heterogeneous mobilome, including a diversity of prophage regions. Our findings provide a better understanding of the diversity of phylogenetically close genomes and expand the knowledge of X. fastidiosa mobile genetic elements and immunity systems.

RevDate: 2022-07-16

Carter MQ, Laniohan N, Lo CC, et al (2022)

Comparative Genomics Applied to Systematically Assess Pathogenicity Potential in Shiga Toxin-Producing Escherichia coli O145:H28.

Microorganisms, 10(5):.

Shiga toxin-producing Escherichia coli (STEC) O145:H28 can cause severe disease in humans and is a predominant serotype in STEC O145 environmental isolates. Here, comparative genomics was applied to a set of clinical and environmental strains to systematically evaluate the pathogenicity potential in environmental strains. While the core genes-based tree separated all O145:H28 strains from the non O145:H28 reference strains, it failed to segregate environmental strains from the clinical. In contrast, the accessory genes-based tree placed all clinical strains in the same clade regardless of their genotypes or serotypes, apart from the environmental strains. Loss-of-function mutations were common in the virulence genes examined, with a high frequency in genes related to adherence, autotransporters, and the type three secretion system. Distinct differences in pathogenicity islands LEE, OI-122, and OI-57, the acid fitness island, and the tellurite resistance island were detected between the O145:H28 and reference strains. A great amount of genetic variation was detected in O145:H28, which was mainly attributed to deletions, insertions, and gene acquisition at several chromosomal "hot spots". Our study demonstrated a distinct virulence gene repertoire among the STEC O145:H28 strains originating from the same geographical region and revealed unforeseen contributions of loss-of-function mutations to virulence evolution and genetic diversification in STEC.

RevDate: 2022-07-16

Liebal UW, Ullmann L, Lieven C, et al (2022)

Ustilago maydis Metabolic Characterization and Growth Quantification with a Genome-Scale Metabolic Model.

Journal of fungi (Basel, Switzerland), 8(5):.

Ustilago maydis is an important plant pathogen that causes corn smut disease and serves as an effective biotechnological production host. The lack of a comprehensive metabolic overview hinders a full understanding of the organism's environmental adaptation and a full use of its metabolic potential. Here, we report the first genome-scale metabolic model (GSMM) of Ustilago maydis (iUma22) for the simulation of metabolic activities. iUma22 was reconstructed from sequencing and annotation using PathwayTools, and the biomass equation was derived from literature values and from the codon composition. The final model contains over 25% annotated genes (6909) in the sequenced genome. Substrate utilization was corrected by BIOLOG phenotype arrays, and exponential batch cultivations were used to test growth predictions. The growth data revealed a decrease in glucose uptake rate with rising glucose concentration. A pangenome of four different U. maydis strains highlighted missing metabolic pathways in iUma22. The new model allows for studies of metabolic adaptations to different environmental niches as well as for biotechnological applications.

RevDate: 2022-07-16
CmpDate: 2022-05-31

Edwards S, León-Zayas R, Ditter R, et al (2022)

Microbial Consortia and Mixed Plastic Waste: Pangenomic Analysis Reveals Potential for Degradation of Multiple Plastic Types via Previously Identified PET Degrading Bacteria.

International journal of molecular sciences, 23(10):.

The global utilization of single-use, non-biodegradable plastics, such as bottles made of polyethylene terephthalate (PET), has contributed to catastrophic levels of plastic pollution. Fortunately, microbial communities are adapting to assimilate plastic waste. Previously, our work showed a full consortium of five bacteria capable of synergistically degrading PET. Using omics approaches, we identified the key genes implicated in PET degradation within the consortium's pangenome and transcriptome. This analysis led to the discovery of a novel PETase, EstB, which has been observed to hydrolyze the oligomer BHET and the polymer PET. Besides the genes implicated in PET degradation, many other biodegradation genes were discovered. Over 200 plastic and plasticizer degradation-related genes were discovered through the Plastic Microbial Biodegradation Database (PMBD). Diverse carbon source utilization was observed by a microbial community-based assay, which, paired with an abundant number of plastic- and plasticizer-degrading enzymes, indicates a promising possibility for mixed plastic degradation. Using RNAseq differential analysis, several genes were predicted to be involved in PET degradation, including aldehyde dehydrogenases and several classes of hydrolases. Active transcription of PET monomer metabolism was also observed, including the generation of polyhydroxyalkanoate (PHA)/polyhydroxybutyrate (PHB) biopolymers. These results present an exciting opportunity for the bio-recycling of mixed plastic waste with upcycling potential.

RevDate: 2022-07-16
CmpDate: 2022-05-31

Wu XT, Xiong ZP, Chen KX, et al (2022)

Genome-Wide Identification and Transcriptional Expression Profiles of PP2C in the Barley (Hordeum vulgare L.) Pan-Genome.

Genes, 13(5):.

The gene family protein phosphatase 2C (PP2C) is related to developmental processes and stress responses in plants. Barley (Hordeum vulgare L.) is a popular cereal crop that is primarily utilized for human consumption and nutrition. However, there is little knowledge regarding the PP2C gene family in barley. In this study, a total of 1635 PP2C genes were identified in 20 barley pan-genome accessions. Then, chromosome localization, physical and chemical feature predictions and subcellular localization were systematically analyzed. One wild barley accession (B1K-04-12) and one cultivated barley (Morex) were chosen as representatives to further analyze and compare the differences in HvPP2Cs between wild and cultivated barley. Phylogenetic analysis showed that these HvPP2Cs were divided into 12 subgroups. Additionally, gene structure, conserved domain and motif, gene duplication event detection, interaction networks and gene expression profiles were analyzed in accessions Morex and B1K-04-12. In addition, qRT-PCR experiments in Morex indicated that seven HvMorexPP2C genes were involved in the response to aluminum and low pH stresses. Finally, a series of positively selected homologous genes were identified between wild accession B1K-04-12 and another 14 cultivated materials, indicating that these genes are important during barley domestication. This work provides a global overview of the putative physiological and biological functions of PP2C genes in barley. We provide a broad framework for understanding the domestication- and evolutionary-induced changes in PP2C genes between wild and cultivated barley.

RevDate: 2022-07-16

Khan K, Basharat Z, Jalal K, et al (2022)

Identification of Therapeutic Targets in an Emerging Gastrointestinal Pathogen Campylobacter ureolyticus and Possible Intervention through Natural Products.

Antibiotics (Basel, Switzerland), 11(5):.

Campylobacter ureolyticus is a Gram-negative, anaerobic, non-spore-forming bacteria that causes gastrointestinal infections. Being the most prevalent cause of bacterial enteritis globally, infection by this bacterium is linked with significant morbidity and mortality in children and immunocompromised patients. No information on pan-therapeutic drug targets for this species is available yet. In the current study, a pan-genome analysis was performed on 13 strains of C. ureolyticus to prioritize potent drug targets from the identified core genome. In total, 26 druggable proteins were identified using subtractive genomics. To the best of the authors' knowledge, this is the first report on the mining of drug targets in C. ureolyticus. UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) was selected as a promiscuous pharmacological target for virtual screening of two bacterial-derived natural product libraries, i.e., postbiotics (n = 78) and streptomycin (n = 737) compounds. LpxC inhibitors from the ZINC database (n = 142 compounds) were also studied with reference to LpxC of C. ureolyticus. The top three docked compounds from each library (including ZINC26844580, ZINC13474902, ZINC13474878, Notoginsenoside St-4, Asiaticoside F, Paraherquamide E, Phytoene, Lycopene, and Sparsomycin) were selected based on their binding energies and validated using molecular dynamics simulations. To help identify potential risks associated with the selected compounds, ADMET profiling was also performed and most of the compounds were considered safe. Our findings may serve as baseline information for laboratory studies leading to the discovery of drugs for use against C. ureolyticus infections.

RevDate: 2022-07-16

Yao E, Blake VC, Cooper L, et al (2022)

GrainGenes: a data-rich repository for small grains genetics and genomics.

Database : the journal of biological databases and curation, 2022:.

As one of the US Department of Agriculture-Agricultural Research Service flagship databases, GrainGenes ( serves the data and community needs of globally distributed small grains researchers for the genetic improvement of the Triticeae family and Avena species that include wheat, barley, rye and oat. GrainGenes accomplishes its mission by continually enriching its cross-linked data content following the findable, accessible, interoperable and reusable principles, enhancing and maintaining an intuitive web interface, creating tools to enable easy data access and establishing data connections within and between GrainGenes and other biological databases to facilitate knowledge discovery. GrainGenes operates within the biological database community, collaborates with curators and genome sequencing groups and contributes to the AgBioData Consortium and the International Wheat Initiative through the Wheat Information System (WheatIS). Interactive and linked content is paramount for successful biological databases and GrainGenes now has 2917 manually curated gene records, including 289 genes and 254 alleles from the Wheat Gene Catalogue (WGC). There are >4.8 million gene models in 51 genome browser assemblies, 6273 quantitative trait loci and >1.4 million genetic loci on 4756 genetic and physical maps contained within 443 mapping sets, complete with standardized metadata. Most notably, 50 new genome browsers that include outputs from the Wheat and Barley PanGenome projects have been created. We provide an example of an expression quantitative trait loci track on the International Wheat Genome Sequencing Consortium Chinese Spring wheat browser to demonstrate how genome browser tracks can be adapted for different data types. To help users benefit more from its data, GrainGenes created four tutorials available on YouTube. GrainGenes is executing its vision of service by continuously responding to the needs of the global small grains community by creating a centralized, long-term, interconnected data repository. Database URL:

RevDate: 2022-07-16

Neuzil-Bunesova V, Ramirez Garcia A, Modrackova N, et al (2022)

Feed Insects as a Reservoir of Granadaene-Producing Lactococci.

Frontiers in microbiology, 13:848490.

Insects are a component of the diet of different animal species and have been suggested as the major source of human dietary protein for the future. However, insects are also carriers of potentially pathogenic microbes that constitute a risk to food and feed safety. In this study, we reported the occurrence of a hemolytic orange pigmented producing phenotype of Lactococcus garvieae/petauri/formosensis in the fecal microbiota of golden lion tamarins (Leontopithecus rosalia) and feed larvae (Zophobas atratus). Feed insects were identified as a regular source of L. garvieae/petauri/formosensis based on a reanalysis of available 16S rRNA gene libraries. Pan-genome analysis suggested the existence of four clusters within the L. garvieae/petauri/formosensis group. The presence of cyl cluster indicated that some strains of the L. garvieae/petauri/formosensis group produced a pigment similar to granadaene, an orange cytotoxic lipid produced by group B streptococci, including Streptococcus agalactiae. Pigment production by L. garvieae/petauri/formosensis strains was dependent on the presence of the fermentable sugars, with no pigment being observed at pH <4.7. The addition of buffering compounds or arginine, which can be metabolized to ammonium, restored pigment formation. In addition, pigment formation might be related to the source of peptone. These data suggest that edible insects are a possible source of granadaene-producing lactococci, which can be considered a pathogenic risk with zoonotic potential.

RevDate: 2022-07-06
CmpDate: 2022-07-06

Bach E, Rangel CP, Ribeiro IDA, et al (2022)

Pangenome analyses of Bacillus pumilus, Bacillus safensis, and Priestia megaterium exploring the plant-associated features of bacilli strains isolated from canola.

Molecular genetics and genomics : MGG, 297(4):1063-1079.

Previous genome mining of the strains Bacillus pumilus 7PB, Bacillus safensis 1TAz, 8Taz, and 32PB, and Priestia megaterium 16PB isolated from canola revealed differences in the profile of antimicrobial biosynthetic genes when compared to the species type strains. To evaluate not only the similarities among B. pumilus, B. safensis, and P. megaterium genomes but also the specificities found in the canola bacilli, we performed comparative genomic analyses through the pangenome evaluation of each species. Besides that, other genome features were explored, especially focusing on plant-associated and biotechnological characteristics. The combination of the genome metrics Average Nucleotide Identity and digital DNA-DNA hybridization formulas 1 and 3 adopting the universal thresholds of 95 and 70%, respectively, was suitable to verify the identification of strains from these groups. On average, core genes corresponded to 45%, 52%, and 34% of B. pumilus, B. safensis, and P. megaterium open pangenomes, respectively. Many genes related to adaptations to plant-associated lifestyles were predicted, especially in the Bacillus genomes. These included genes for acetoin production, polyamines utilization, root exudate chemoreceptors, biofilm formation, and plant cell-wall degrading enzymes. Overall, we could observe that strains of these species exhibit many features in common, whereas most of their variable genome portions have features yet to be uncovered. The observed antifungal activity of canola bacilli might be a result of the synergistic action of secondary metabolites, siderophores, and chitinases. Genome analysis confirmed that these species and strains have biotechnological potential to be used both as agricultural inoculants or hydrolases producers. Up to our knowledge, this is the first work that evaluates the pangenome features of P. megaterium.


ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

ESP Content

When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

ESP Help

Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).


ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.


Biographical information about many key scientists.

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 07 JUL 2018 )