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Arizala D, Arif M. Impact of Homologous Recombination on Core Genome Evolution and Host Adaptation of Pectobacterium parmentieri. Genome Biol Evol 2024; 16:evae032. [PMID: 38385549 PMCID: PMC10946231 DOI: 10.1093/gbe/evae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/02/2024] [Accepted: 02/11/2024] [Indexed: 02/23/2024] Open
Abstract
Homologous recombination is a major force mechanism driving bacterial evolution, host adaptability, and acquisition of novel virulence traits. Pectobacterium parmentieri is a plant bacterial pathogen distributed worldwide, primarily affecting potatoes, by causing soft rot and blackleg diseases. The goal of this investigation was to understand the impact of homologous recombination on the genomic evolution of P. parmentieri. Analysis of P. parmentieri genomes using Roary revealed a dynamic pan-genome with 3,742 core genes and over 55% accessory genome variability. Bayesian population structure analysis identified 7 lineages, indicating species heterogeneity. ClonalFrameML analysis displayed 5,125 recombination events, with the lineage 4 exhibiting the highest events. fastGEAR analysis identified 486 ancestral and 941 recent recombination events ranging from 43 bp to 119 kb and 36 bp to 13.96 kb, respectively, suggesting ongoing adaptation. Notably, 11% (412 genes) of the core genome underwent recent recombination, with lineage 1 as the main donor. The prevalence of recent recombination (double compared to ancient) events implies continuous adaptation, possibly driven by global potato trade. Recombination events were found in genes involved in vital cellular processes (DNA replication, DNA repair, RNA processing, homeostasis, and metabolism), pathogenicity determinants (type secretion systems, cell-wall degrading enzymes, iron scavengers, lipopolysaccharides (LPS), flagellum, etc.), antimicrobial compounds (phenazine and colicin) and even CRISPR-Cas genes. Overall, these results emphasize the potential role of homologous recombination in P. parmentieri's evolutionary dynamics, influencing host colonization, pathogenicity, adaptive immunity, and ecological fitness.
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Affiliation(s)
- Dario Arizala
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Mohammad Arif
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
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Kim W, Jeon H, Lee H, Sohn KH, Segonzac C. The Ralstonia pseudosolanacearum Type III Effector RipL Delays Flowering and Promotes Susceptibility to Pseudomonas syringae in Arabidopsis thaliana. Mol Cells 2023; 46:710-724. [PMID: 37968984 PMCID: PMC10654456 DOI: 10.14348/molcells.2023.0127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/20/2023] [Accepted: 09/24/2023] [Indexed: 11/17/2023] Open
Abstract
The plant defense responses to microbial infection are tightly regulated and integrated with the developmental program for optimal resources allocation. Notably, the defense- associated hormone salicylic acid (SA) acts as a promoter of flowering while several plant pathogens actively target the flowering signaling pathway to promote their virulence or dissemination. Ralstonia pseudosolanacearum inject tens of effectors in the host cells that collectively promote bacterial proliferation in plant tissues. Here, we characterized the function of the broadly conserved R. pseudosolanacearum effector RipL, through heterologous expression in Arabidopsis thaliana . RipL-expressing transgenic lines presented a delayed flowering, which correlated with a low expression of flowering regulator genes. Delayed flowering was also observed in Nicotiana benthamiana plants transiently expressing RipL. In parallel, RipL promoted plant susceptibility to virulent strains of Pseudomonas syringae in the effector-expressing lines or when delivered by the type III secretion system. Unexpectedly, SA accumulation and SA-dependent immune signaling were not significantly affected by RipL expression. Rather, the RNA-seq analysis of infected RipL-expressing lines revealed that the overall amplitude of the transcriptional response was dampened, suggesting that RipL could promote plant susceptibility in an SA-independent manner. Further elucidation of the molecular mechanisms underpinning RipL effect on flowering and immunity may reveal novel effector functions in host cells.
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Affiliation(s)
- Wanhui Kim
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Korea
| | - Hyelim Jeon
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Korea
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea
| | - Hyeonjung Lee
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Kee Hoon Sohn
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea
| | - Cécile Segonzac
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Korea
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea
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Baroukh C, Cottret L, Pires E, Peyraud R, Guidot A, Genin S. Insights into the metabolic specificities of pathogenic strains from the Ralstonia solanacearum species complex. mSystems 2023; 8:e0008323. [PMID: 37341493 PMCID: PMC10470067 DOI: 10.1128/msystems.00083-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 04/14/2023] [Indexed: 06/22/2023] Open
Abstract
All the strains grouped under the species Ralstonia solanacearum represent a species complex responsible for many diseases on agricultural crops throughout the world. The strains have different lifestyles and host range. Here, we investigated whether specific metabolic pathways contribute to strain diversification. To this end, we carried out systematic comparisons on 11 strains representing the diversity of the species complex. We reconstructed the metabolic network of each strain from its genome sequence and looked for the metabolic pathways differentiating the different reconstructed networks and, by extension, the different strains. Finally, we conducted an experimental validation by determining the metabolic profile of each strain with the Biolog technology. Results revealed that the metabolism is conserved between strains, with a core metabolism composed of 82% of the pan-reactome. The three species composing the species complex could be distinguished according to the presence/absence of some metabolic pathways, in particular, one involving salicylic acid degradation. Phenotypic assays revealed that the trophic preferences on organic acids and several amino acids such as glutamine, glutamate, aspartate, and asparagine are conserved between strains. Finally, we generated mutants lacking the quorum-sensing-dependent regulator PhcA in four diverse strains, and we showed that the phcA-dependent trade-off between growth and production of virulence factors is conserved across the R. solanacearum species complex. IMPORTANCE Ralstonia solanacearum is one of the most important threats to plant health worldwide, causing disease on a very large range of agricultural crops such as tomato or potato. Behind the R. solanacearum name are hundreds of strains with different host range and lifestyle, classified into three species. Studying the differences between strains allows to better apprehend the biology of the pathogens and the specificity of some strains. None of the published genomic comparative studies have focused on the metabolism of the strains so far. We developed a new bioinformatic pipeline to build high-quality metabolic networks and used a combination of metabolic modeling and high-throughput phenotypic Biolog microplates to look for the metabolic differences between 11 strains across the three species. Our study revealed that genes encoding enzymes are overall conserved, with few variations between strains. However, more variations were observed when considering substrate usage. These variations probably result from regulation rather than the presence or absence of enzymes in the genome.
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Affiliation(s)
- Caroline Baroukh
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Ludovic Cottret
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Emma Pires
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Rémi Peyraud
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Alice Guidot
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Stéphane Genin
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
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Plant-Pathogenic Ralstonia Phylotypes Evolved Divergent Respiratory Strategies and Behaviors To Thrive in Xylem. mBio 2023; 14:e0318822. [PMID: 36744950 PMCID: PMC9973335 DOI: 10.1128/mbio.03188-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bacterial pathogens in the Ralstonia solanacearum species complex (RSSC) infect the water-transporting xylem vessels of plants, causing bacterial wilt disease. Strains in RSSC phylotypes I and III can reduce nitrate to dinitrogen via complete denitrification. The four-step denitrification pathway enables bacteria to use inorganic nitrogen species as terminal electron acceptors, supporting their growth in oxygen-limited environments such as biofilms or plant xylem. Reduction of nitrate, nitrite, and nitric oxide all contribute to the virulence of a model phylotype I strain. However, little is known about the physiological role of the last denitrification step, the reduction of nitrous oxide to dinitrogen by NosZ. We found that phylotypes I and III need NosZ for full virulence. However, strains in phylotypes II and IV are highly virulent despite lacking NosZ. The ability to respire by reducing nitrate to nitrous oxide does not greatly enhance the growth of phylotype II and IV strains. These partial denitrifying strains reach high cell densities during plant infection and cause typical wilt disease. However, unlike phylotype I and III strains, partial denitrifiers cannot grow well under anaerobic conditions or form thick biofilms in culture or in tomato xylem vessels. Furthermore, aerotaxis assays show that strains from different phylotypes have different oxygen and nitrate preferences. Together, these results indicate that the RSSC contains two subgroups that occupy the same habitat but have evolved divergent energy metabolism strategies to exploit distinct metabolic niches in the xylem. IMPORTANCE Plant-pathogenic Ralstonia spp. are a heterogeneous globally distributed group of bacteria that colonize plant xylem vessels. Ralstonia cells multiply rapidly in plants and obstruct water transport, causing fatal wilting and serious economic losses of many key food security crops. The virulence of these pathogens depends on their ability to grow to high cell densities in the low-oxygen xylem environment. Plant-pathogenic Ralstonia can use denitrifying respiration to generate ATP. The last denitrification step, nitrous oxide reduction by NosZ, contributes to energy production and virulence for only one of the three phytopathogenic Ralstonia species. These complete denitrifiers form thicker biofilms in culture and in tomato xylem, suggesting they are better adapted to hypoxic niches. Strains with partial denitrification physiology form less biofilm and are more often planktonic. They are nonetheless highly virulent. Thus, these closely related bacteria have adapted their core metabolic functions to exploit distinct microniches in the same habitat.
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Greenrod STE, Stoycheva M, Elphinstone J, Friman VP. Global diversity and distribution of prophages are lineage-specific within the Ralstonia solanacearum species complex. BMC Genomics 2022; 23:689. [PMID: 36199029 PMCID: PMC9535894 DOI: 10.1186/s12864-022-08909-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
Background Ralstonia solanacearum species complex (RSSC) strains are destructive plant pathogenic bacteria and the causative agents of bacterial wilt disease, infecting over 200 plant species worldwide. In addition to chromosomal genes, their virulence is mediated by mobile genetic elements including integrated DNA of bacteriophages, i.e., prophages, which may carry fitness-associated auxiliary genes or modulate host gene expression. Although experimental studies have characterised several prophages that shape RSSC virulence, the global diversity, distribution, and wider functional gene content of RSSC prophages are unknown. In this study, prophages were identified in a diverse collection of 192 RSSC draft genome assemblies originating from six continents. Results Prophages were identified bioinformatically and their diversity investigated using genetic distance measures, gene content, GC, and total length. Prophage distributions were characterised using metadata on RSSC strain geographic origin and lineage classification (phylotypes), and their functional gene content was assessed by identifying putative prophage-encoded auxiliary genes. In total, 313 intact prophages were identified, forming ten genetically distinct clusters. These included six prophage clusters with similarity to the Inoviridae, Myoviridae, and Siphoviridae phage families, and four uncharacterised clusters, possibly representing novel, previously undescribed phages. The prophages had broad geographical distributions, being present across multiple continents. However, they were generally host phylogenetic lineage-specific, and overall, prophage diversity was proportional to the genetic diversity of their hosts. The prophages contained many auxiliary genes involved in metabolism and virulence of both phage and bacteria. Conclusions Our results show that while RSSC prophages are highly diverse globally, they make lineage-specific contributions to the RSSC accessory genome, which could have resulted from shared coevolutionary history. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08909-7.
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Affiliation(s)
| | | | - John Elphinstone
- Fera Science Ltd, National Agri-Food Innovation Campus, Sand Hutton, York, UK
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Geng R, Cheng L, Cao C, Liu Z, Liu D, Xiao Z, Wu X, Huang Z, Feng Q, Luo C, Chen Z, Zhang Z, Jiang C, Ren M, Yang A. Comprehensive Analysis Reveals the Genetic and Pathogenic Diversity of Ralstonia solanacearum Species Complex and Benefits Its Taxonomic Classification. Front Microbiol 2022; 13:854792. [PMID: 35602040 PMCID: PMC9121018 DOI: 10.3389/fmicb.2022.854792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/22/2022] [Indexed: 11/23/2022] Open
Abstract
Ralstonia solanacearum species complex (RSSC) is a diverse group of plant pathogens that attack a wide range of hosts and cause devastating losses worldwide. In this study, we conducted a comprehensive analysis of 131 RSSC strains to detect their genetic diversity, pathogenicity, and evolution dynamics. Average nucleotide identity analysis was performed to explore the genomic relatedness among these strains, and finally obtained an open pangenome with 32,961 gene families. To better understand the diverse evolution and pathogenicity, we also conducted a series of analyses of virulence factors (VFs) and horizontal gene transfer (HGT) in the pangenome and at the single genome level. The distribution of VFs and mobile genetic elements (MGEs) showed significant differences among different groups and strains, which were consistent with the new nomenclatures of the RSSC with three distinct species. Further functional analysis showed that most HGT events conferred from Burkholderiales and played a great role in shaping the genomic plasticity and genetic diversity of RSSC genomes. Our work provides insights into the genetic polymorphism, evolution dynamics, and pathogenetic variety of RSSC and provides strong supports for the new taxonomic classification, as well as abundant resources for studying host specificity and pathogen emergence.
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Affiliation(s)
- Ruimei Geng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Lirui Cheng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Changdai Cao
- Shandong Rizhao Tobacco Company Ltd., Rizhao, China
| | - Zhengwen Liu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Dan Liu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhiliang Xiao
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Xiuming Wu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhenrui Huang
- Key Laboratory of Crop Genetic Improvement, Engineering and Technology Research Center for Tobacco Breeding and Comprehensive Utilization of Guangdong, Crops Research Institute of Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Quanfu Feng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Chenggang Luo
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhiqiang Chen
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhenchen Zhang
- Key Laboratory of Crop Genetic Improvement, Engineering and Technology Research Center for Tobacco Breeding and Comprehensive Utilization of Guangdong, Crops Research Institute of Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Caihong Jiang
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Min Ren
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
- *Correspondence: Min Ren,
| | - Aiguo Yang
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
- Aiguo Yang,
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Sharma P, Johnson MA, Mazloom R, Allen C, Heath LS, Lowe-Power TM, Vinatzer BA. Meta-analysis of the Ralstonia solanacearum species complex (RSSC) based on comparative evolutionary genomics and reverse ecology. Microb Genom 2022; 8:000791. [PMID: 35297758 PMCID: PMC9176288 DOI: 10.1099/mgen.0.000791] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ralstonia solanacearum species complex (RSSC) strains are bacteria that colonize plant xylem tissue and cause vascular wilt diseases. However, individual strains vary in host range, optimal disease temperatures and physiological traits. To increase our understanding of the evolution, diversity and biology of the RSSC, we performed a meta-analysis of 100 representative RSSC genomes. These 100 RSSC genomes contain 4940 genes on average, and a pangenome analysis found that there are 3262 genes in the core genome (~60 % of the mean RSSC genome) with 13 128 genes in the extensive flexible genome. A core genome phylogenetic tree and a whole-genome similarity matrix aligned with the previously named species (R. solanacearum, R. pseudosolanacearum, R. syzygii) and phylotypes (I–IV). These analyses also highlighted a third unrecognized sub-clade of phylotype II. Additionally, we identified differences between phylotypes with respect to gene content and recombination rate, and we delineated population clusters based on the extent of horizontal gene transfer. Multiple analyses indicate that phylotype II is the most diverse phylotype, and it may thus represent the ancestral group of the RSSC. We also used our genome-based framework to test whether the RSSC sequence variant (sequevar) taxonomy is a robust method to define within-species relationships of strains. The sequevar taxonomy is based on alignments of a single conserved gene (egl). Although sequevars in phylotype II describe monophyletic groups, the sequevar system breaks down in the highly recombinogenic phylotype I, which highlights the need for an improved, cost-effective method for genotyping strains in phylotype I. Finally, we enabled quick and precise genome-based identification of newly sequenced RSSC strains by assigning Life Identification Numbers (LINs) to the 100 strains and by circumscribing the RSSC and its sub-groups in the LINbase Web service.
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Affiliation(s)
- Parul Sharma
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA
- Graduate Program in Genetics, Bioinformatics and Computational Biology, Virginia Tech, Blacksburg, VA, USA
| | - Marcela A. Johnson
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA
- Graduate Program in Genetics, Bioinformatics and Computational Biology, Virginia Tech, Blacksburg, VA, USA
| | - Reza Mazloom
- Department of Computer Science, Virginia Tech, Blacksburg, VA, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Lenwood S. Heath
- Department of Computer Science, Virginia Tech, Blacksburg, VA, USA
| | - Tiffany M. Lowe-Power
- Department of Plant Pathology, University of California Davis, Davis, CA, USA
- *Correspondence: Tiffany M. Lowe-Power,
| | - Boris A. Vinatzer
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA
- *Correspondence: Boris A. Vinatzer,
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Colombi E, Perry BJ, Sullivan JT, Bekuma AA, Terpolilli JJ, Ronson CW, Ramsay JP. Comparative analysis of integrative and conjugative mobile genetic elements in the genus Mesorhizobium. Microb Genom 2021; 7. [PMID: 34605762 PMCID: PMC8627217 DOI: 10.1099/mgen.0.000657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Members of the Mesorhizobium genus are soil bacteria that often form nitrogen-fixing symbioses with legumes. Most characterised Mesorhizobium spp. genomes are ~8 Mb in size and harbour extensive pangenomes including large integrative and conjugative elements (ICEs) carrying genes required for symbiosis (ICESyms). Here, we document and compare the conjugative mobilome of 41 complete Mesorhizobium genomes. We delineated 56 ICEs and 24 integrative and mobilizable elements (IMEs) collectively occupying 16 distinct integration sites, along with 24 plasmids. We also demonstrated horizontal transfer of the largest (853,775 bp) documented ICE, the tripartite ICEMspSymAA22. The conjugation systems of all identified ICEs and several plasmids were related to those of the paradigm ICESym ICEMlSymR7A, with each carrying conserved genes for conjugative pilus formation (trb), excision (rdfS), DNA transfer (rlxS) and regulation (fseA). ICESyms have likely evolved from a common ancestor, despite occupying a variety of distinct integration sites and specifying symbiosis with diverse legumes. We found extensive evidence for recombination between ICEs and particularly ICESyms, which all uniquely lack the conjugation entry-exclusion factor gene trbK. Frequent duplication, replacement and pseudogenization of genes for quorum-sensing-mediated activation and antiactivation of ICE transfer suggests ICE transfer regulation is constantly evolving. Pangenome-wide association analysis of the ICE identified genes potentially involved in symbiosis, rhizosphere colonisation and/or adaptation to distinct legume hosts. In summary, the Mesorhizobium genus has accumulated a large and dynamic pangenome that evolves through ongoing horizontal gene transfer of large conjugative elements related to ICEMlSymR7A.
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Affiliation(s)
- Elena Colombi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,Curtin Medical School, Curtin University, Perth, WA, Australia
| | - Benjamin J Perry
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - John T Sullivan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Amanuel A Bekuma
- Centre for Rhizobium Studies, Food Futures Institute, Murdoch University, Perth, WA, Australia, Murdoch University, Perth, WA, Australia.,Present address: Western Australian Department of Primary Industries and Regional Development, Research and Industry Innovation, South Perth, WA, Australia
| | - Jason J Terpolilli
- Centre for Rhizobium Studies, Food Futures Institute, Murdoch University, Perth, WA, Australia, Murdoch University, Perth, WA, Australia
| | - Clive W Ronson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Joshua P Ramsay
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,Curtin Medical School, Curtin University, Perth, WA, Australia
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Moon H, Pandey A, Yoon H, Choi S, Jeon H, Prokchorchik M, Jung G, Witek K, Valls M, McCann HC, Kim M, Jones JDG, Segonzac C, Sohn KH. Identification of RipAZ1 as an avirulence determinant of Ralstonia solanacearum in Solanum americanum. MOLECULAR PLANT PATHOLOGY 2021; 22:317-333. [PMID: 33389783 PMCID: PMC7865085 DOI: 10.1111/mpp.13030] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/07/2020] [Accepted: 11/23/2020] [Indexed: 05/08/2023]
Abstract
Ralstonia solanacearum causes bacterial wilt disease in many plant species. Type III-secreted effectors (T3Es) play crucial roles in bacterial pathogenesis. However, some T3Es are recognized by corresponding disease resistance proteins and activate plant immunity. In this study, we identified the R. solanacearum T3E protein RipAZ1 (Ralstonia injected protein AZ1) as an avirulence determinant in the black nightshade species Solanum americanum. Based on the S. americanum accession-specific avirulence phenotype of R. solanacearum strain Pe_26, 12 candidate avirulence T3Es were selected for further analysis. Among these candidates, only RipAZ1 induced a cell death response when transiently expressed in a bacterial wilt-resistant S. americanum accession. Furthermore, loss of ripAZ1 in the avirulent R. solanacearum strain Pe_26 resulted in acquired virulence. Our analysis of the natural sequence and functional variation of RipAZ1 demonstrated that the naturally occurring C-terminal truncation results in loss of RipAZ1-triggered cell death. We also show that the 213 amino acid central region of RipAZ1 is sufficient to induce cell death in S. americanum. Finally, we show that RipAZ1 may activate defence in host cell cytoplasm. Taken together, our data indicate that the nucleocytoplasmic T3E RipAZ1 confers R. solanacearum avirulence in S. americanum. Few avirulence genes are known in vascular bacterial phytopathogens and ripAZ1 is the first one in R. solanacearum that is recognized in black nightshades. This work thus opens the way for the identification of disease resistance genes responsible for the specific recognition of RipAZ1, which can be a source of resistance against the devastating bacterial wilt disease.
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Affiliation(s)
- Hayoung Moon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Ankita Pandey
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hayeon Yoon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Sera Choi
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hyelim Jeon
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Maxim Prokchorchik
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Gayoung Jung
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Kamil Witek
- The Sainsbury LaboratoryUniversity of East AngliaNorwichUK
| | - Marc Valls
- Department of GeneticsUniversity of BarcelonaBarcelonaSpain
- Centre for Research in Agricultural Genomics (CSIC‐IRTA‐UAB‐UB)BellaterraSpain
| | - Honour C. McCann
- New Zealand Institute of Advanced StudiesMassey UniversityAucklandNew Zealand
- Max Planck Institute for Developmental BiologyTübingenGermany
| | - Min‐Sung Kim
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- Division of Integrative Biosciences and BiotechnologyPohang University of Science and TechnologyRepublic of Korea
| | | | - Cécile Segonzac
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
- Department of Plant Science, Plant Genomics and Breeding InstituteAgricultural Life Science Research InstituteSeoul National UniversitySeoulRepublic of Korea
| | - Kee Hoon Sohn
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- School of Interdisciplinary Bioscience and BioengineeringPohang University of Science and TechnologyPohangRepublic of Korea
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Abstract
Population genomics is transforming our understanding of pathogen biology and evolution, and contributing to the prevention and management of disease in diverse crops. We provide an overview of key methods in bacterial population genomics and describe recent work focusing on three topics of critical importance to plant pathology: (i) resolving pathogen origins and transmission pathways during outbreak events, (ii) identifying the genetic basis of host specificity and virulence, and (iii) understanding how pathogens evolve in response to changing agricultural practices.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Christina Straub
- Institute of Environmental Science and Research, Health and Environment, Auckland, New Zealand
- Genomics Aotearoa, New Zealand
| | - Elena Colombi
- Curtin Health Innovation Research Institute (CHIRI), Curtin University, Perth, Western Australia, Australia
- School of Pharmacy and Biomedical Sciences, Curtin University, Perth, Western Australia, Australia
| | - Honour C McCann
- New Zealand Institute for Advanced Study, Massey University, Albany, New Zealand
- Max Planck Institute for Developmental Biology, Tübingen, Germany
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