scholarly journals Pan-Genome-Wide Analysis of Pantoea ananatis Identified Genes Linked to Pathogenicity in Onion

2021 ◽  
Vol 12 ◽  
Author(s):  
Gaurav Agarwal ◽  
Divya Choudhary ◽  
Shaun P. Stice ◽  
Brendon K. Myers ◽  
Ronald D. Gitaitis ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Gene Cluster ◽  
Core Genome ◽  
Bacterial Colonization ◽  
Secretion Systems ◽  
Pantoea Ananatis ◽  
Novel Genes ◽  
Pan Genome ◽  
Niche Adaptation ◽  
Genome Wide

Pantoea ananatis, a gram negative and facultative anaerobic bacterium is a member of a Pantoea spp. complex that causes center rot of onion, which significantly affects onion yield and quality. This pathogen does not have typical virulence factors like type II or type III secretion systems but appears to require a biosynthetic gene-cluster, HiVir/PASVIL (located chromosomally comprised of 14 genes), for a phosphonate secondary metabolite, and the ‘alt’ gene cluster (located in plasmid and comprised of 11 genes) that aids in bacterial colonization in onion bulbs by imparting tolerance to thiosulfinates. We conducted a deep pan-genome-wide association study (pan-GWAS) to predict additional genes associated with pathogenicity in P. ananatis using a panel of diverse strains (n = 81). We utilized a red-onion scale necrosis assay as an indicator of pathogenicity. Based on this assay, we differentiated pathogenic (n = 51)- vs. non-pathogenic (n = 30)-strains phenotypically. Pan-genome analysis revealed a large core genome of 3,153 genes and a flexible accessory genome. Pan-GWAS using the presence and absence variants (PAVs) predicted 42 genes, including 14 from the previously identified HiVir/PASVIL cluster associated with pathogenicity, and 28 novel genes that were not previously associated with pathogenicity in onion. Of the 28 novel genes identified, eight have annotated functions of site-specific tyrosine kinase, N-acetylmuramoyl-L-alanine amidase, conjugal transfer, and HTH-type transcriptional regulator. The remaining 20 genes are currently hypothetical. Further, a core-genome SNPs-based phylogeny and horizontal gene transfer (HGT) studies were also conducted to assess the extent of lateral gene transfer among diverse P. ananatis strains. Phylogenetic analysis based on PAVs and whole genome multi locus sequence typing (wgMLST) rather than core-genome SNPs distinguished red-scale necrosis inducing (pathogenic) strains from non-scale necrosis inducing (non-pathogenic) strains of P. ananatis. A total of 1182 HGT events including the HiVir/PASVIL and alt cluster genes were identified. These events could be regarded as a major contributing factor to the diversification, niche-adaptation and potential acquisition of pathogenicity/virulence genes in P. ananatis.

scholarly journals Pan-Genome-Wide Analysis of Pantoea Ananatis Identified Genes Linked to Pathogenicity in Onion

2020 ◽  
Author(s):  
Gaurav Agarwal ◽  
Divya Choudhary ◽  
Shaun Stice ◽  
Brendon Myers ◽  
Ronald Gitaitis ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Transcriptional Regulator ◽  
Phylogenomic Analysis ◽  
Secretion Systems ◽  
Pantoea Ananatis ◽  
Novel Genes ◽  
Pan Genome ◽  
Niche Adaptation ◽  
Genome Wide ◽  
Presence And Absence

Abstract Background: Pantoea ananatis is a member of a Pantoea spp. complex that causes center rot of onion, which significantly affects onion yield and quality. This pathogen does not have typical virulence factors like type II or type III secretion systems but appears to require a biosynthetic gene-cluster, HiVir/PASVIL (located chromosomally), for a phosphonate secondary metabolite, and the onion-virulence regions, OVR (localized on a megaplasmid), for onion pathogenicity and virulence, respectively. Results: We conducted a deep pan-genome-wide association study (pan-GWAS) to predict additional genes associated with pathogenicity in P. ananatis using a panel of diverse strains (n = 81). We utilized a red-onion scale necrosis assay as an indicator of pathogenicity. Based on this assay, we differentiated pathogenic (n = 51) - vs. non-pathogenic (n = 30)-strains phenotypically. Pan-GWAS revealed a large core genome of 3,153 genes and a flexible accessory genome of ≤5,065 genes. Phylogenomic analysis using pan-GWAS and presence and absence variants (PAVs) distinguished red-scale necrosis inducing (pathogenic) strains from non-scale necrosis inducing (non-pathogenic) strains of P. ananatis. The pan-GWAS also predicted 42 genes, including 14 from the previously identified HiVir/PASVIL cluster associated with pathogenicity, and 28 novel genes that were not previously associated with pathogenicity in onion. Of the 28 novel genes identified, eight have annotated functions of site-specific tyrosine kinase, N-acetylmuramoyl-L-alanine amidase, TraR/DksA family transcriptional regulator, and HTH-type transcriptional regulator. The remaining 20 genes are currently hypothetical. Conclusions: This is the first report of using pan-GWAS on P. ananatis for the prediction of novel genes contributing to pathogenicity in onion, which will be utilized for further functional analyses. Pan-genomic differences (using PAVs) differentiated onion pathogenic from non-pathogenic strains of P. ananatis, which has been difficult to achieve using single or multiple gene-based phylogenetic analyses. The pan-genome analysis also allowed us to evaluate the presence and absence of HiVir/PASVIL genes and 11 megaplasmid-borne OVR-A genes regarded as the ‘alt’ cluster that aid in P. ananatis colonization in onion bulbs. We concluded that HiVir/PASVIL genes are associated with pathogenic P. ananatis strains and the alt gene cluster alone is not responsible for pathogenicity on onion. The pan-genome also provides clear evidence of constantly evolving accessory genes in P. ananatis that may contribute to host-range expansion and niche-adaptation.

scholarly journals Pan-genome-wide analysis of Pantoea ananatis identified genes linked to pathogenicity in onion

2020 ◽  
Author(s):  
Gaurav Agarwal ◽  
Divya Choudhary ◽  
Shaun P. Stice ◽  
Brendon K. Myers ◽  
Ronald D. Gitaitis ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Genome Analysis ◽  
Core Genome ◽  
Genome Wide Association Study ◽  
Transcriptional Regulator ◽  
Pantoea Ananatis ◽  
Novel Genes ◽  
Pan Genome ◽  
Genome Wide ◽  
Presence And Absence

AbstractPantoea ananatis is a member of a Pantoea spp. complex that causes center rot of onion, which significantly affects onion yield and quality. This pathogen does not have typical virulence factors like type II or type III secretion systems but appears to require a biosynthetic gene-cluster, HiVir/PASVIL (located chromosomally), for a phosphonate secondary metabolite, and the onion-virulence regions, OVR (localized on a megaplasmid), for onion pathogenicity and virulence, respectively. We conducted a deep pan-genome-wide association study (pan-GWAS) to predict additional genes associated with pathogenicity in P. ananatis using a panel of diverse strains (n = 81). We utilized a red-onion scale necrosis assay as an indicator of pathogenicity. Based on this assay, we differentiated pathogenic (n = 51)- vs. non-pathogenic (n = 30)-strains phenotypically. Pan-GWAS revealed a large core genome of 3,153 genes and a flexible accessory genome of ≤5,065 genes. Phylogenomic analysis using pan-GWAS and presence and absence variants (PAVs) distinguished red-scale necrosis inducing (pathogenic) strains from non-scale necrosis inducing (non-pathogenic) strains of P. ananatis. The pan-GWAS also predicted 42 genes, including 14 from the previously identified HiVir/PASVIL cluster associated with pathogenicity, and 28 novel genes that were not previously associated with pathogenicity in onion. Of the 28 novel genes identified, eight have annotated functions of site-specific tyrosine kinase, N-acetylmuramoyl-L-alanine amidase, TraR/DksA family transcriptional regulator, and HTH-type transcriptional regulator. The remaining 20 genes are currently hypothetical. This is the first report of using pan-GWAS on P. ananatis for the prediction of novel genes contributing to pathogenicity in onion, which will be utilized for further functional analyses. Pan-genomic differences (using PAVs) differentiated onion pathogenic from non-pathogenic strains of P. ananatis, which has been difficult to achieve using single or multiple gene-based phylogenetic analyses. The pan-genome analysis also allowed us to evaluate the presence and absence of HiVir/PASVIL genes and 11 megaplasmid-borne OVR-A genes regarded as the ‘alt’ cluster that aid in P. ananatis colonization in onion bulbs. We concluded that HiVir/PASVIL genes are associated with pathogenic P. ananatis strains and the alt gene cluster alone is not responsible for pathogenicity on onion. The pan-genome also provides clear evidence of constantly evolving accessory genes in P. ananatis that may contribute to host-range expansion and niche-adaptation.Author summaryPantoea ananatis is a major bacterial pathogen that causes center rot of onion and diseases of a number of other plant species. In order to understand the genome architecture and identify genes responsible for pathogenicity in onion, a pan-genome analysis was performed. We used 81 strains of P. ananatis collected over 20 years from different regions of the state of Georgia, USA. The pan-genome study identified a core genome with a conserved set of genes and an accessory genome that displayed variation among strains. We conducted pan-GWAS (pan-genome-wide association study) using presence and absence variants (PAVs) in the genomes and associated onion-pathogenic phenotypes based on a red-onion scale necrosis assay. The study resulted in identification of genes, including a cluster of chromosomal HiVir/PASVIL genes, that are significantly associated with the onion pathogenic phenotype. In addition, we identified 28 novel genes, a majority of which (n = 20) have hypothetical functions. We concluded and further substantiated earlier findings that a cluster of genes is responsible for pathogenicity on onion. The pan-genome analysis also allowed us to evaluate the presence and absence of HiVir/PASVIL genes and 11 megaplasmid-borne OVR-A genes regarded as the ‘alt’ cluster that aid in bacterial colonization of onion bulbs by P. ananatis strains. We concluded that HiVir/PASVIL genes are associated with onion-pathogenic strains, and the alt gene cluster alone is not responsible for pathogenicity on onion. This study also provides potential evidence of constantly evolving accessory genes in P. ananatis which may help in host range expansion and adaptation to diverse niches.

scholarly journals Pan-Genome of Novel Pantoea stewartii subsp. indologenes Reveals Genes Involved in Onion Pathogenicity and Evidence of Lateral Gene Transfer

2021 ◽  
Vol 9 (8) ◽  
pp. 1761
Author(s):  
Gaurav Agarwal ◽  
Ronald D. Gitaitis ◽  
Bhabesh Dutta
Keyword(s):  
Gene Transfer ◽  
Core Genome ◽  
Foxtail Millet ◽  
Gene Clusters ◽  
Evaluation Study ◽  
Full Spectrum ◽  
Pan Genome ◽  
Pantoea Stewartii ◽  
Comparative Phylogenetic Analysis ◽  
Core Genes

Pantoea stewartii subsp. indologenes (Psi) is a causative agent of leafspot on foxtail millet and pearl millet; however, novel strains were recently identified that are pathogenic on onions. Our recent host range evaluation study identified two pathovars; P. stewartii subsp. indologenes pv. cepacicola pv. nov. and P. stewartii subsp. indologenes pv. setariae pv. nov. that are pathogenic on onions and millets or on millets only, respectively. In the current study, we developed a pan-genome using the whole genome sequencing of newly identified/classified Psi strains from both pathovars [pv. cepacicola (n = 4) and pv. setariae (n = 13)]. The full spectrum of the pan-genome contained 7030 genes. Among these, 3546 (present in genomes of all 17 strains) were the core genes that were a subset of 3682 soft-core genes (present in ≥16 strains). The accessory genome included 1308 shell genes and 2040 cloud genes (present in ≤2 strains). The pan-genome showed a clear linear progression with >6000 genes, suggesting that the pan-genome of Psi is open. Comparative phylogenetic analysis showed differences in phylogenetic clustering of Pantoea spp. using PAVs/wgMLST approach in comparison with core genome SNPs-based phylogeny. Further, we conducted a horizontal gene transfer (HGT) study using Psi strains from both pathovars along with strains from other Pantoea species, namely, P. stewartii subsp. stewartii LMG 2715T, P. ananatis LMG 2665T, P. agglomerans LMG L15, and P. allii LMG 24248T. A total of 317 HGT events among four Pantoea species were identified with most gene transfer events occurring between Psi pv. cepacicola and Psi pv. setariae. Pan-GWAS analysis predicted a total of 154 genes, including seven gene-clusters, which were associated with the pathogenicity phenotype (necrosis on seedling) on onions. One of the gene-clusters contained 11 genes with known functions and was found to be chromosomally located.

scholarly journals Pan-genome of Novel Pantoea stewartii subsp. indologenes Reveal Genes Involved in Onion Pathogenicity and Evidence of Lateral Gene Transfer

2021 ◽  
Author(s):  
Gaurav Agarwal ◽  
Ronald D. Gitaitis ◽  
Bhabesh Dutta
Keyword(s):  
Gene Transfer ◽  
Core Genome ◽  
Foxtail Millet ◽  
Evaluation Study ◽  
Full Spectrum ◽  
The Core ◽  
Pan Genome ◽  
Pantoea Stewartii ◽  
Comparative Phylogenetic Analysis ◽  
Core Genes

Pantoea stewartii subsp. indologenes (Psi) is a causative agent of leafspot of foxtail millet and pearl millet; however, novel strains were recently identified that are pathogenic on onion. Our recent host range evaluation study identified two pathovars; P. stewartii subsp. indologenes pv. cepacicola pv. nov. and P. stewartii subsp. indologenes pv. setariae pv. nov. that are pathogenic on onion and millets or on millets only, respectively. In the current study we developed a pan-genome using the whole genome sequencing of newly identified/classified Psi strains from both pathovars [pv. cepacicola (n= 4) and pv. setariae (n=13)]. The full spectrum of the pan-genome contained 7,030 genes. Among these, 3,546 (present in genomes of all 17 strains) were the core genes that were a subset of 3,682 soft-core genes (present in ≥16 strains). The accessory genome included 1,308 shell genes and 2,040 cloud genes (present in ≤ 2 strains). The pan-genome showed a clear liner progression with >6,000 genes, suggesting the pan-genome of Psi is open. Comparative phylogenetic analysis showed differences in phylogenetic clustering of Pantoea spp. using PAVs/wgMLST approach in comparison to core genome SNP-based phylogeny. Further, we conducted a horizontal gene transfer (HGT) study including four other Pantoea species namely, P. stewartii subsp. stewartii LMG 2715T, P. ananatis LMG 2665T, P. agglomerans LMG L15, and P. allii LMG 24248T. A total of 317 HGT events among four Pantoea species were identified with most gene transfers observed between Psi pv. cepacicola and Psi pv. setariae. Pan-GWAS analysis predicted a total of 154 genes including seven cluster of genes associated with the pathogenicity phenotype on onion. One of the clusters contain 11 genes with known functions and are found to be chromosomally located.

scholarly journals Pan-GWAS of Streptococcus agalactiae Highlights Lineage-Specific Genes Associated with Virulence and Niche Adaptation

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Andrea Gori ◽  
Odile B. Harrison ◽  
Ethwako Mlia ◽  
Yo Nishihara ◽  
Jia Mun Chan ◽  
...  
Keyword(s):  
Association Study ◽  
Low Income ◽  
Streptococcus Agalactiae ◽  
Genome Wide Association Study ◽  
Genome Wide Association ◽  
Low Income Countries ◽  
Less Invasive ◽  
Pan Genome ◽  
Niche Adaptation ◽  
Genome Wide

ABSTRACT Streptococcus agalactiae (group B streptococcus; GBS) is a colonizer of the gastrointestinal and urogenital tracts, and an opportunistic pathogen of infants and adults. The worldwide population of GBS is characterized by clonal complexes (CCs) with different invasive potentials. CC17, for example, is a hypervirulent lineage commonly associated with neonatal sepsis and meningitis, while CC1 is less invasive in neonates and more commonly causes invasive disease in adults with comorbidities. The genetic basis of GBS virulence and the extent to which different CCs have adapted to different host environments remain uncertain. We have therefore applied a pan-genome-wide association study (GWAS) approach to 1,988 GBS strains isolated from different hosts and countries. Our analysis identified 279 CC-specific genes associated with virulence, disease, metabolism, and regulation of cellular mechanisms that may explain the differential virulence potential of particular CCs. In CC17 and CC23, for example, we have identified genes encoding pilus, quorum-sensing proteins, and proteins for the uptake of ions and micronutrients which are absent in less invasive lineages. Moreover, in CC17, carriage and disease strains were distinguished by the allelic variants of 21 of these CC-specific genes. Together our data highlight the lineage-specific basis of GBS niche adaptation and virulence. IMPORTANCE GBS is a leading cause of mortality in newborn babies in high- and low-income countries worldwide. Different strains of GBS are characterized by different degrees of virulence, where some are harmlessly carried by humans or animals and others are much more likely to cause disease. The genome sequences of almost 2,000 GBS samples isolated from both animals and humans in high- and low- income countries were analyzed using a pan-genome-wide association study approach. This allowed us to identify 279 genes which are associated with different lineages of GBS, characterized by a different virulence and preferred host. Additionally, we propose that the GBS now carried in humans may have first evolved in animals before expanding clonally once adapted to the human host. These findings are essential to help understand what is causing GBS disease and how the bacteria have evolved and are transmitted.

scholarly journals Pantoea ananatis defeats Allium chemical defenses with a plasmid-borne virulence gene cluster

2020 ◽  
Author(s):  
Shaun P. Stice ◽  
Kyle K. Thao ◽  
Chang Hyun Khang ◽  
David A. Baltrus ◽  
Bhabesh Dutta ◽  
...  
Keyword(s):  
Cell Death ◽  
Gene Cluster ◽  
Arms Race ◽  
Cellular Damage ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Secretion Systems ◽  
Pantoea Ananatis ◽  
Type Iii ◽  
Necrotic Symptoms

AbstractOnion (Allium. cepa L), garlic (A. sativum L.), and other members of the Allium genus produce volatile antimicrobial thiosulfinates upon cellular damage. Allicin has been known since the 1950s as the primary antimicrobial thiosulfinate compound and odorant produced by garlic. However, the roles of endogenous thiosulfinate production in host-bacterial pathogen interactions have not been described. The bacterial onion pathogen Pantoea ananatis, which lacks both the virulence Type III and Type II Secretion Systems, induces necrotic symptoms and extensive cell death in onion tissues dependent on a proposed secondary metabolite synthesis chromosomal gene cluster. We found strong correlation between the genetic requirements for P. ananatis to colonize necrotized onion tissue and its capacity for tolerance to the thiosulfinate allicin based on the presence of an eleven gene, plasmid-borne, virulence cluster of sulfur/redox genes. We have designated them ‘alt’ genes for allicin tolerance. We show that allicin and onion thiosulfinates restrict bacterial growth with similar kinetics. The alt gene cluster is sufficient to confer allicin tolerance and protects the glutathione pool during allicin treatment. Independent alt genes make partial phenotypic contributions indicating that they function as a collective cohort to manage thiol stress. Our work implicates endogenous onion thiosulfinates produced during cellular damage as mediators of interactions with bacteria. The P. ananatis-onion pathosystem can be modeled as a chemical arms race of pathogen attack, host chemical counter-attack, and pathogen resistance.Significance StatementAlliums (e.g. onion and garlic), after sustaining cellular damage, produce potent antimicrobial thiosulfinates that react with cellular thiols. The bacterial onion pathogen Pantoea ananatis, which lacks the virulence Type III and Type II Secretion Systems, induces cell death and necrotic symptoms on onions. We have identified a plasmid-borne cluster of sulfur/redox virulence genes that 1) are required for P. ananatis to colonize necrotized onion tissue, 2) are sufficient for tolerance to the thiosulfinates, and, 3) protect the glutathione pool during thiosulfinate treatment. We propose that the thiosulfinate production potential of Allium spp. governs Allium-bacterial interaction outcomes and that the P. ananatis-onion pathosystem can be modeled as a chemical arms race of attack and counterattack between the pathogen and host.

scholarly journals Comparative genomic analysis of Mycobacterium tuberculosis reveals evolution and genomic instability within Uganda I sub-lineage

2020 ◽  
Author(s):  
Stephen Kanyerezi ◽  
Patricia Nabisubi
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Core Genome ◽  
Variant Calling ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Genome Wide Association ◽  
Comparative Genomic ◽  
Pan Genome ◽  
Genome Wide

AbstractIntroductionTuberculosis (TB) is the leading cause of morbidity and mortality globally, responsible for an estimated annual 10.0 million new cases and 1.3 million deaths among infectious diseases with Africa contributing a quarter of these cases in 2019. Classification of Mycobacterium tuberculosis (MTB) strains is important in understanding their geographical predominance and pathogenicity. Different studies have gone ahead to classify MTB using different methods. Some of these include; RFLP, spoligotyping, MIRU-VNTR and SNP set based phylogeny. The SNP set based classification has been found to be in concordance with the region of difference (RD) analysis of MTB complex classification system. In Uganda, the most common cause of pulmonary tuberculosis (PTB) is Uganda genotype of MTB and accounts for up to 70 % of isolates.MethodsSequenced MTB genome samples were retrieved from NCBI and others from local sequencing projects. The genomes were subjected to snippy (a rapid haploid variant calling and core genome alignment) to call variants and annotate them. Outputs from snippy were used to classify the isolates into Uganda genotypes and Non Ugandan genotypes based on 62 SNP set. The Ugandan genotype isolates were later subjected to 413 SNP set and then to a pan genome wide association analysis.Results6 Uganda genotype isolates were found not to classify as either Uganda I or II genotypes based on the 62 SNP set. Using the 413 SNP set, the 6 Uganda genotype isolates were found to have only one SNP out of the 7 SNPs that classify the Uganda I genotypes. They were also found to have both missense and frameshift mutations within the ctpH gene whereas the rest of Uganda I that had a mutation within this gene, was a missense.ConclusionAmong the Uganda genotypes genomes, Uganda I genomes are unstable. We used publicly available datasets to perform analysis like mapping, variant calling, mixed infection, pan-genome analysis to investigate and compare evolution of the Ugandan genotype.

Establishment of a genome-wide RNAi screen; Identification of novel genes involved in clonal maintenance of ALL

2014 ◽  
Vol 226 (03) ◽  
Author(s):  
F Ponthan ◽  
D Pal ◽  
J Vormoor ◽  
O Heidenreich
Keyword(s):  
Rnai Screen ◽  
Novel Genes ◽  
Genome Wide ◽  
A Genome

A Caution in Association of ABO Blood Group with COVID-19

2020 ◽  
Keyword(s):  
Gene Cluster ◽  
Clinical Outcomes ◽  
Blood Group ◽  
Association Analysis ◽  
Blood Type ◽  
Genome Wide Association ◽  
Chromosome 3 ◽  
Abo Blood Group ◽  
Genome Wide Association Analysis ◽  
Genome Wide

A comment on Zhao J, Yang Y, Huang H, Li D, Gu D, Lu X, et al. Association of ABO blood group and Covid19 susceptability. medRxiv [PREPRINT]. 2020; https://doi.org/10.1101/2020.03.11.20031096. Zeng X, Fan H, Lu D, Huang F, Meng X, Li Z, et al. Association between ABO blood group and clinical outcomes of Covid19. medRxiv[PREPRINT].2020; https://doi.org/10.1101/2020.04.15.20063107. Zietz M, Tatonetti N. Testing the association between blood type and COVID-19 infection, intubation, and death medRxiv [PREPRINT]. 2020; https://doi.org/10.1101/2020.04.08.20058073. Ellinghaus D, Degenhardt F, Bujanda L, al. e. The ABO blood group and a chromosome 3 gene cluster associate with SRAS-CoV2 respitarory failure in an Italy-Spain genome-wide association analysis. medRxiv. 2020; https://doi.org/10.1101/2020.05.31.20114991.

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