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Holtappels D, Abelson SA, Nouth SC, Rickus GEJ, Amare SZ, Giller JP, Jian DZ, Koskella B. Genomic characterization of Pseudomonas syringae pv. syringae from Callery pear and the efficiency of associated phages in disease protection. Microbiol Spectr 2024; 12:e0283323. [PMID: 38323825 PMCID: PMC10913373 DOI: 10.1128/spectrum.02833-23] [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: 07/14/2023] [Accepted: 12/11/2023] [Indexed: 02/08/2024] Open
Abstract
The Pseudomonas syringae species complex is a heterogeneous group of plant pathogenic bacteria associated with a wide distribution of plant species. Advances in genomics are revealing the complex evolutionary history of this species complex and the wide array of genetic adaptations underpinning their diverse lifestyles. Here, we genomically characterize two P. syringae isolates collected from diseased Callery pears (Pyrus calleryana) in Berkeley, California in 2019 and 2022. We also isolated a lytic bacteriophage, which we characterized and evaluated for biocontrol efficiency. Using a multilocus sequence analysis and core genome alignment, we classified the P. syringae isolates as members of phylogroup 2, related to other strains previously isolated from Pyrus and Prunus. An analysis of effector proteins demonstrated an evolutionary conservation of effectoromes across isolates classified in PG2 and yet uncovered unique effector profiles for each, including the two newly identified isolates. Whole-genome sequencing of the associated phage uncovered a novel phage genus related to Pseudomonas syringae pv. actinidiae phage PHB09 and the Flaumdravirus genus. Finally, using in planta infection assays, we demonstrate that the phage was equally useful in symptom mitigation of immature pear fruit regardless of the Pss strain tested. Overall, this study demonstrates the diversity of P. syringae and their viruses associated with ornamental pear trees, posing spill-over risks to commercial pear trees and the possibility of using phages as biocontrol agents to reduce the impact of disease.IMPORTANCEGlobal change exacerbates the spread and impact of pathogens, especially in agricultural settings. There is a clear need to better monitor the spread and diversity of plant pathogens, including in potential spillover hosts, and for the development of novel and sustainable control strategies. In this study, we characterize the first described strains of Pseudomonas syringae pv. syringae isolated from Callery pear in Berkeley, California from diseased tissues in an urban environment. We show that these strains have divergent virulence profiles from previously described strains and that they can cause disease in commercial pears. Additionally, we describe a novel bacteriophage that is associated with these strains and explore its potential to act as a biocontrol agent. Together, the data presented here demonstrate that ornamental pear trees harbor novel P. syringae pv. syringae isolates that potentially pose a risk to local fruit production, or vice versa-but also provide us with novel associated phages, effective in disease mitigation.
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Affiliation(s)
- D. Holtappels
- Integrative Biology University of California, Berkeley, California, USA
| | - S. A. Abelson
- Integrative Biology University of California, Berkeley, California, USA
| | - S. C. Nouth
- Integrative Biology University of California, Berkeley, California, USA
| | - G. E. J. Rickus
- Integrative Biology University of California, Berkeley, California, USA
| | - S. Z. Amare
- Integrative Biology University of California, Berkeley, California, USA
| | - J. P. Giller
- Integrative Biology University of California, Berkeley, California, USA
| | - D. Z. Jian
- Integrative Biology University of California, Berkeley, California, USA
| | - B. Koskella
- Integrative Biology University of California, Berkeley, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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2
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Relevance of prokaryotic subspecies in the age of genomics. New Microbes New Infect 2022; 48:101024. [PMID: 36176539 PMCID: PMC9513812 DOI: 10.1016/j.nmni.2022.101024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 08/13/2022] [Accepted: 08/22/2022] [Indexed: 11/20/2022] Open
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3
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Wang Y, Pruitt RN, Nürnberger T, Wang Y. Evasion of plant immunity by microbial pathogens. Nat Rev Microbiol 2022; 20:449-464. [PMID: 35296800 DOI: 10.1038/s41579-022-00710-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 57.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2022] [Indexed: 12/21/2022]
Abstract
Plant pathogenic viruses, bacteria, fungi and oomycetes cause destructive diseases in natural habitats and agricultural settings, thereby threatening plant biodiversity and global food security. The capability of plants to sense and respond to microbial infection determines the outcome of plant-microorganism interactions. Host-adapted microbial pathogens exploit various infection strategies to evade or counter plant immunity and eventually establish a replicative niche. Evasion of plant immunity through dampening host recognition or the subsequent immune signalling and defence execution is a crucial infection strategy used by different microbial pathogens to cause diseases, underpinning a substantial obstacle for efficient deployment of host genetic resistance genes for sustainable disease control. In this Review, we discuss current knowledge of the varied strategies microbial pathogens use to evade the complicated network of plant immunity for successful infection. In addition, we discuss how to exploit this knowledge to engineer crop resistance.
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Affiliation(s)
- Yan Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China.,The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Rory N Pruitt
- Centre for Molecular Biology of Plants (ZMBP), University of Tübingen, Tübingen, Germany
| | - Thorsten Nürnberger
- Centre for Molecular Biology of Plants (ZMBP), University of Tübingen, Tübingen, Germany.,Department of Biochemistry, University of Johannesburg, Johannesburg, South Africa
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China. .,The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China.
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4
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Li Y, Zhu Q, Zhi T, Fan R, Xie T, Zhao Z, Long Y, Li Z. Genetic Causes of Non-pathogenic Pseudomonas syringae pv. actinidiae Isolates in Kiwifruit Orchards. Front Microbiol 2021; 12:650099. [PMID: 33841374 PMCID: PMC8027508 DOI: 10.3389/fmicb.2021.650099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/08/2021] [Indexed: 11/13/2022] Open
Abstract
Bacterial canker disease has become the largest threat to kiwifruit cultivation and production. A monomorphic subpopulation of Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) is responsible for the pandemic worldwide. Diversity in pathogenicity has been found in the pandemic subpopulation and in other Psa3 subpopulations causing epidemics in China. However, the genetic bases have not yet been elucidated. In this study, 117 Psa3 isolates were identified by Psa- and Psa3-specific primers, and evaluated for pathogenicity. Three isolates G4, G40, and S2 are not pathogenic to kiwifruit and do not elicit hypersensitivity responses (HRs) in non-host Nicotiana benthamiana leaves. Two isolates, G25 and G35, exhibited attenuated HR-eliciting activity in non-host N. benthamiana, but they exhibited greatly and slightly reduced pathogenicity in host plants, respectively. The genomes of the five isolates were sequenced and compared with closely related isolates revealed by MLVA and whole-genome typing methods. The candidate genetic loci responsible for the changes in pathogenicity and HR elicitation, were further evaluated by allele replacement experiments. We found that the three non-pathogenic isolates were formed due to the independent, identical insertion events of ISPsy36 transposon in the hrpR gene, encoding a key regulator of type III secretion system (T3SS) and type III effectors (T3Es). In the symptomatic sample from which G4 was isolated, 27% HR negative isolates were detected. In isolate G25, transposon insertion of ISPsy32 at the non-coding sequence upstream of the hrpR gene was detected, similar to a previously reported low-virulent Psa3 strain M227. In isolate G35, we detected disruptions of T3Es hopBB1-1 and hopBB1-2, which induce HR in N. benthamiana leaves revealed by Agrobacterium tumefaciens infiltration. These phenotype-changed isolates were formed at low frequencies during the course of pathogen infection in host plants, supported by the binding assay of ISPsy32 and the non-coding DNA sequences upstream of the hrpR gene, the co-isolation of the virulent isolates belonging to the same MLVA clade, and the low levels of transcription of the transposon genes. Taken together, in terms of short-term field evolution, transposon insertions in the T3SS-related genes resulted in the formation of non-pathogenic and low-virulent Psa3 isolates.
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Affiliation(s)
- Yue Li
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
| | - Qiaomei Zhu
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
| | - Taihui Zhi
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
| | - Rong Fan
- Kiwifruit Engineering and Technology Research Center, Guizhou University, Guiyang, China
| | - Ting Xie
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
| | - Zhibo Zhao
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China.,Kiwifruit Engineering and Technology Research Center, Guizhou University, Guiyang, China
| | - Youhua Long
- Kiwifruit Engineering and Technology Research Center, Guizhou University, Guiyang, China
| | - Zhong Li
- Department of Plant Pathology, College of Agriculture, Guizhou University, Guiyang, China
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5
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Bakhshi Ganje M, Mackay J, Nicolaisen M, Shams-Bakhsh M. Comparative Genomics, Pangenome, and Phylogenomic Analyses of Brenneria spp., and Delineation of Brenneria izadpanahii sp. nov. PHYTOPATHOLOGY 2021; 111:78-95. [PMID: 32407252 DOI: 10.1094/phyto-04-20-0129-fi] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Brenneria species are bacterial plant pathogens mainly affecting woody plants. Association of all members with devastating disorders (e.g., acute oak decline in Iran and United Kingdom) are due to adaptation and pathogenic behavior in response to host and environmental factors. Some species, including B. goodwinii, B. salicis, and B. nigrifluens, also show endophytic residence. Here we show that all species including novel Brenneria sp. are closely related. Gene-based and genome/pangenome-based phylogeny divide the genus into two distinct lineages, Brenneria clades A and B. The two clades were functionally distinct and were consistent with their common and special potential activities as determined via annotation of functional domains. Pangenome analysis demonstrated that the core pathogenicity factors were highly conserved, an hrp gene cluster encoding a type III secretion system was found in all species except B. corticis. An extensive repertoire of candidate virulence factors was identified. Comparative genomics indicated a repertoire of plant cell wall degrading enzymes, metabolites/antibiotics, and numerous prophages providing new insights into Brenneria-host interactions and appropriate targets for further characterization. This work not only documented the genetic differentiation of Brenneria species but also delineates a more functionally driven understanding of Brenneria by comparison with relevant Pectobacteriaceae thereby substantially enriching the extent of information available for functional genomic investigations.
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Affiliation(s)
- Meysam Bakhshi Ganje
- Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
| | - John Mackay
- Department of Plant Sciences, University of Oxford, Oxford, U.K
| | - Mogens Nicolaisen
- Faculty of Science and Technology, Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200, Slagelse, Denmark
| | - Masoud Shams-Bakhsh
- Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
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6
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Gonçalves OS, Campos KF, de Assis JCS, Fernandes AS, Souza TS, do Carmo Rodrigues LG, Queiroz MVD, Santana MF. Transposable elements contribute to the genome plasticity of Ralstonia solanacearum species complex. Microb Genom 2020; 6. [PMID: 32379020 PMCID: PMC7371123 DOI: 10.1099/mgen.0.000374] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The extensive genetic diversity of Ralstonia solanacearum, a serious soil-borne phytopathogen, has led to the concept that R. solanacearum encompasses a species complex [R. solanacearum species complex (RSSC)]. Insertion sequences (ISs) are suggested to play an important role in the genome evolution of this pathogen. Here, we identified and analysed transposable elements (TEs), ISs and transposons, in 106 RSSC genomes and 15 Ralstonia spp. We mapped 10 259 IS elements in the complete genome of 62 representative RSSC strains and closely related Ralstonia spp. A unique set of 20 IS families was widespread across the strains, IS5 and IS3 being the most abundant. Our results showed six novel transposon sequences belonging to the Tn3 family carrying passenger genes encoding antibiotic resistance and avirulence proteins. In addition, internal rearrangement events associated with ISs were demonstrated in Ralstonia pseudosolanacearum strains. We also mapped IS elements interrupting avirulence genes, which provided evidence that ISs plays an important role in virulence evolution of RSSC. Additionally, the activity of ISs was demonstrated by transcriptome analysis and DNA hybridization in R. solanacearum isolates. Altogether, we have provided collective data of TEs in RSSC genomes, opening a new path for understanding their evolutionary impact on the genome evolution and diversity of this important plant pathogen.
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Affiliation(s)
- Osiel Silva Gonçalves
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Kiara França Campos
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Jéssica Catarine Silva de Assis
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Alexia Suellen Fernandes
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Thamires Santos Souza
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Luiz Guilherme do Carmo Rodrigues
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Marisa Vieira de Queiroz
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
| | - Mateus Ferreira Santana
- Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil
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7
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Laflamme B, Dillon MM, Martel A, Almeida RND, Desveaux D, Guttman DS. The pan-genome effector-triggered immunity landscape of a host-pathogen interaction. Science 2020; 367:763-768. [PMID: 32054757 DOI: 10.1126/science.aax4079] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/18/2019] [Accepted: 01/17/2020] [Indexed: 12/24/2022]
Abstract
Effector-triggered immunity (ETI), induced by host immune receptors in response to microbial effectors, protects plants against virulent pathogens. However, a systematic study of ETI prevalence against species-wide pathogen diversity is lacking. We constructed the Pseudomonas syringae Type III Effector Compendium (PsyTEC) to reduce the pan-genome complexity of 5127 unique effector proteins, distributed among 70 families from 494 strains, to 529 representative alleles. We screened PsyTEC on the model plant Arabidopsis thaliana and identified 59 ETI-eliciting alleles (11.2%) from 19 families (27.1%), with orthologs distributed among 96.8% of P. syringae strains. We also identified two previously undescribed host immune receptors, including CAR1, which recognizes the conserved effectors AvrE and HopAA1, and found that 94.7% of strains harbor alleles predicted to be recognized by either CAR1 or ZAR1.
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Affiliation(s)
- Bradley Laflamme
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Marcus M Dillon
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Alexandre Martel
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Renan N D Almeida
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Darrell Desveaux
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada.
| | - David S Guttman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada. .,Center for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada
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8
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Poon JSY, Le Fevre RE, Carr JP, Hanke DE, Murphy AM. Inositol hexakisphosphate biosynthesis underpins PAMP-triggered immunity to Pseudomonas syringae pv. tomato in Arabidopsis thaliana but is dispensable for establishment of systemic acquired resistance. MOLECULAR PLANT PATHOLOGY 2020; 21:376-387. [PMID: 31876373 PMCID: PMC7036367 DOI: 10.1111/mpp.12902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 05/27/2023]
Abstract
Phytic acid (inositol hexakisphosphate, InsP6 ) is an important phosphate store and signal molecule necessary for maintenance of basal resistance to plant pathogens. Arabidopsis thaliana ('arabidopsis') has three genes encoding myo-inositol phosphate synthases (IPS1-3), the enzymes that catalyse conversion of glucose-6-phosphate to InsP, the first step in InsP6 biosynthesis. There is one gene for inositol-(1,3,4,5,6)-pentakisphosphate 2-kinase (IPK1), which catalyses the final step. Previously, we showed that mutation of IPS2 and IPK1 but not IPS1 increased susceptibility to pathogens. Our aim was to better understand the InsP6 biosynthesis pathway in plant defence. Here we found that the susceptibility of arabidopsis (Col-0) to virulent and avirulent Pseudomonas syringae pv. tomato was also increased in ips3 and ips2/3 double mutants. Also, ipk1 plants had compromised expression of local acquired resistance induced by treatment with the pathogen-derived molecular pattern (PAMP) molecule flg22, but were unaffected in other responses to flg22, including Ca2+ influx and the oxidative burst, seedling root growth inhibition, and transcriptional up-regulation of the PAMP-triggered genes MITOGEN-ACTIVATED PROTEIN KINASE (MPK) 3, MPK11, CINNAMYL ALCOHOL DEHYDROGENASE 5, and FLG22-INDUCED RECEPTOR-LIKE KINASE 1. IPK1 mutation did not prevent the induction of systemic acquired resistance by avirulent P. syringae. Also, ips2 and ips2/3 double mutant plants, like ipk1, were hypersusceptible to P. syringae but were not compromised in flg22-induced local acquired resistance. The results support the role of InsP6 biosynthesis enzymes in effective basal resistance and indicate that there is more than one basal resistance mechanism dependent upon InsP6 biosynthesis.
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Affiliation(s)
| | - Ruth E. Le Fevre
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| | - John P. Carr
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| | - David E. Hanke
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
| | - Alex M. Murphy
- Department of Plant SciencesUniversity of CambridgeCambridgeUnited Kingdom
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9
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Hulin MT, Armitage AD, Vicente JG, Holub EB, Baxter L, Bates HJ, Mansfield JW, Jackson RW, Harrison RJ. Comparative genomics of Pseudomonas syringae reveals convergent gene gain and loss associated with specialization onto cherry (Prunus avium). THE NEW PHYTOLOGIST 2018; 219:672-696. [PMID: 29726587 DOI: 10.1111/nph.15182] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/22/2018] [Indexed: 05/12/2023]
Abstract
Genome-wide analyses of the effector- and toxin-encoding genes were used to examine the phylogenetics and evolution of pathogenicity amongst diverse strains of Pseudomonas syringae causing bacterial canker of cherry (Prunus avium), including pathovars P. syringae pv morsprunorum (Psm) races 1 and 2, P. syringae pv syringae (Pss) and P. syringae pv avii. Phylogenetic analyses revealed Psm races and P. syringae pv avii clades were distinct and were each monophyletic, whereas cherry-pathogenic strains of Pss were interspersed amongst strains from other host species. A maximum likelihood approach was used to predict effectors associated with pathogenicity on cherry. Pss possesses a smaller repertoire of type III effectors but has more toxin biosynthesis clusters than Psm and P. syringae pv avii. Evolution of cherry pathogenicity was correlated with gain of genes such as hopAR1 and hopBB1 through putative phage transfer and horizontal transfer respectively. By contrast, loss of the avrPto/hopAB redundant effector group was observed in cherry-pathogenic clades. Ectopic expression of hopAB and hopC1 triggered the hypersensitive reaction in cherry leaves, confirming computational predictions. Cherry canker provides a fascinating example of convergent evolution of pathogenicity that is explained by the mix of effector and toxin repertoires acting on a common host.
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Affiliation(s)
- Michelle T Hulin
- NIAB EMR, New Road, East Malling, ME19 6BJ, UK
- School of Biological Sciences, University of Reading, Reading, RG6 6AJ, UK
| | | | - Joana G Vicente
- School of Life Sciences, Warwick Crop Centre, University of Warwick, Wellesbourne, CV35 9EF, UK
| | - Eric B Holub
- School of Life Sciences, Warwick Crop Centre, University of Warwick, Wellesbourne, CV35 9EF, UK
| | - Laura Baxter
- School of Life Sciences, Warwick Crop Centre, University of Warwick, Wellesbourne, CV35 9EF, UK
| | | | - John W Mansfield
- Faculty of Natural Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, RG6 6AJ, UK
| | - Richard J Harrison
- NIAB EMR, New Road, East Malling, ME19 6BJ, UK
- School of Biological Sciences, University of Reading, Reading, RG6 6AJ, UK
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10
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Sundin GW, Wang N, Charkowski AO, Castiblanco LF, Jia H, Zhao Y. Perspectives on the Transition From Bacterial Phytopathogen Genomics Studies to Applications Enhancing Disease Management: From Promise to Practice. PHYTOPATHOLOGY 2016; 106:1071-1082. [PMID: 27183301 DOI: 10.1094/phyto-03-16-0117-fi] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The advent of genomics has advanced science into a new era, providing a plethora of "toys" for researchers in many related and disparate fields. Genomics has also spawned many new fields, including proteomics and metabolomics, furthering our ability to gain a more comprehensive view of individual organisms and of interacting organisms. Genomic information of both bacterial pathogens and their hosts has provided the critical starting point in understanding the molecular bases of how pathogens disrupt host cells to cause disease. In addition, knowledge of the complete genome sequence of the pathogen provides a potentially broad slate of targets for the development of novel virulence inhibitors that are desperately needed for disease management. Regarding plant bacterial pathogens and disease management, the potential for utilizing genomics resources in the development of durable resistance is enhanced because of developing technologies that enable targeted modification of the host. Here, we summarize the role of genomics studies in furthering efforts to manage bacterial plant diseases and highlight novel genomics-enabled strategies heading down this path.
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Affiliation(s)
- George W Sundin
- First and fourth authors: Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing; second and fifth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Science, University of Florida, Lake Alfred; third author: Department of Plant Pathology, University of Wisconsin-Madison; sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign
| | - Nian Wang
- First and fourth authors: Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing; second and fifth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Science, University of Florida, Lake Alfred; third author: Department of Plant Pathology, University of Wisconsin-Madison; sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign
| | - Amy O Charkowski
- First and fourth authors: Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing; second and fifth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Science, University of Florida, Lake Alfred; third author: Department of Plant Pathology, University of Wisconsin-Madison; sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign
| | - Luisa F Castiblanco
- First and fourth authors: Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing; second and fifth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Science, University of Florida, Lake Alfred; third author: Department of Plant Pathology, University of Wisconsin-Madison; sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign
| | - Hongge Jia
- First and fourth authors: Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing; second and fifth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Science, University of Florida, Lake Alfred; third author: Department of Plant Pathology, University of Wisconsin-Madison; sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign
| | - Youfu Zhao
- First and fourth authors: Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing; second and fifth authors: Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Science, University of Florida, Lake Alfred; third author: Department of Plant Pathology, University of Wisconsin-Madison; sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign
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11
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Johansson ON, Nilsson AK, Gustavsson MB, Backhaus T, Andersson MX, Ellerström M. A quick and robust method for quantification of the hypersensitive response in plants. PeerJ 2015; 3:e1469. [PMID: 26734506 PMCID: PMC4699783 DOI: 10.7717/peerj.1469] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/12/2015] [Indexed: 01/28/2023] Open
Abstract
One of the most studied defense reactions of plants against microbial pathogens is the hypersensitive response (HR). The HR is a complex multicellular process that involves programmed cell death at the site of infection. A standard method to quantify plant defense and the HR is to measure the release of cellular electrolytes into water after infiltration with pathogenic bacteria. In this type of experiment, the bacteria are typically delivered into the plant tissue through syringe infiltration. Here we report the development of a vacuum infiltration protocol that allows multiple plant lines to be infiltrated simultaneously and assayed for defense responses. Vacuum infiltration did not induce more wounding response in Arabidopsis leaf tissue than syringe inoculation, whereas throughput and reproducibility were improved. The method was used to study HR-induced electrolyte loss after treatment with the bacterium Pseudomonas syringae pv. tomato DC3000 harboring the effector AvrRpm1, AvrRpt2 or AvrRps4. Specifically, the influence of bacterial titer on AvrRpm1-induced HR was investigated. Not only the amplitude, but also the timing of the maximum rate of the HR reaction was found to be dose-dependent. Finally, using vacuum infiltration, we were able quantify induction of phospholipase D activity after AvrRpm1 recognition in leaves labeled with (33)PO4.
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Affiliation(s)
- Oskar N Johansson
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anders K Nilsson
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Mikael B Gustavsson
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Thomas Backhaus
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Mats X Andersson
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Mats Ellerström
- Department of Biology and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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Escalon A, Javegny S, Vernière C, Noël LD, Vital K, Poussier S, Hajri A, Boureau T, Pruvost O, Arlat M, Gagnevin L. Variations in type III effector repertoires, pathological phenotypes and host range of Xanthomonas citri pv. citri pathotypes. MOLECULAR PLANT PATHOLOGY 2013; 14:483-96. [PMID: 23437976 PMCID: PMC6638789 DOI: 10.1111/mpp.12019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The mechanisms determining the host range of Xanthomonas are still undeciphered, despite much interest in their potential roles in the evolution and emergence of plant pathogenic bacteria. Xanthomonas citri pv. citri (Xci) is an interesting model of host specialization because of its pathogenic variants: pathotype A strains infect a wide range of Rutaceous species, whereas pathotype A*/A(W) strains have a host range restricted to Mexican lime (Citrus aurantifolia) and alemow (Citrus macrophylla). Based on a collection of 55 strains representative of Xci worldwide diversity assessed by amplified fragment length polymorphism (AFLP), we investigated the distribution of type III effectors (T3Es) in relation to host range. We examined the presence of 66 T3Es from xanthomonads in Xci and identified a repertoire of 28 effectors, 26 of which were shared by all Xci strains, whereas two (xopAG and xopC1) were present only in some A*/A(W) strains. We found that xopAG (=avrGf1) was present in all A(W) strains, but also in three A* strains genetically distant from A(W) , and that all xopAG-containing strains induced the hypersensitive response (HR) on grapefruit and sweet orange. The analysis of xopAD and xopAG suggested horizontal transfer between X. citri pv. bilvae, another citrus pathogen, and some Xci strains. A strains were genetically less diverse, induced identical phenotypic responses and possessed indistinguishable T3E repertoires. Conversely, A*/A(W) strains exhibited a wider genetic diversity in which clades correlated with geographical origin and T3E repertoire, but not with pathogenicity, according to T3E deletion experiments. Our data outline the importance of taking into account the heterogeneity of Xci A*/A(W) strains when analysing the mechanisms of host specialization.
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Affiliation(s)
- Aline Escalon
- UMR PVBMT, CIRAD, F-97410 Saint-Pierre, La Réunion, France
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13
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Abstract
The resiliency and adaptive ability of microbial life in real time on Earth relies heavily upon horizontal gene transfer. Based on that knowledge, how likely is earth based microbial life to colonize extraterrestrial targets such as Mars? To address this question, we consider manned and unmanned space exploration, the resident microbiota that is likely to inhabit those vehicles, the adaptive potential of that microbiota in an extraterrestrial setting especially with regards to mobile genetic elements, and the likelihood that Mars like environments could initiate and sustain colonization.
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14
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Scortichini M, Marcelletti S, Ferrante P, Petriccione M, Firrao G. Pseudomonas syringae pv. actinidiae: a re-emerging, multi-faceted, pandemic pathogen. MOLECULAR PLANT PATHOLOGY 2012; 13:631-40. [PMID: 22353258 PMCID: PMC6638780 DOI: 10.1111/j.1364-3703.2012.00788.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Pseudomonas syringae pv. actinidiae is the causal agent of bacterial canker of green-fleshed kiwifruit (Actinidia deliciosa) and yellow-fleshed kiwifruit (A. chinensis). A recent, sudden, re-emerging wave of this disease has occurred, almost contemporaneously, in all of the main areas of kiwifruit production in the world, suggesting that it can be considered as a pandemic disease. Recent in-depth genetic studies performed on P. syringae pv. actinidiae strains have revealed that this pathovar is composed of four genetically different populations which, to different extents, can infect crops of the genus Actinidia worldwide. Genome comparisons of these strains have revealed that this pathovar can gain and lose the phaseolotoxin gene cluster, as well as mobile genetic elements, such as plasmids and putative prophages, and that it can modify the repertoire of the effector gene arrays. In addition, the strains currently causing worldwide severe economic losses display an extensive set of genes related to the ecological fitness of the bacterium in planta, such as copper and antibiotic resistance genes, multiple siderophore genes and genes involved in the degradation of lignin derivatives and other phenolics. This pathogen can therefore easily colonize hosts throughout the year. TAXONOMY Bacteria; Proteobacteria, gamma subdivision; Order Pseudomonadales; Family Pseudomonadaceae; Genus Pseudomonas; Pseudomonas syringae species complex, genomospecies 8; Pathovar actinidiae. MICROBIOLOGICAL PROPERTIES Gram-negative, aerobic, motile, rod-shaped, polar flagella, oxidase-negative, arginine dihydrolase-negative, DNA 58.5-58.8 mol.% GC, elicits the hypersensitive response on tobacco leaves. HOST RANGE Primarily studied as the causal agent of bacterial canker of green-fleshed kiwifruit (Actinidia deliciosa), it has also been isolated from yellow-fleshed kiwifruit (A. chinensis). In both species, it causes severe economic losses worldwide. It has also been isolated from wild A. arguta and A. kolomikta. DISEASE SYMPTOMS In green-fleshed and yellow-fleshed kiwifruits, the symptoms include brown-black leaf spots often surrounded by a chlorotic margin, blossom necrosis, extensive twig die-back, reddening of the lenticels, extensive cankers along the main trunk and leader, and bleeding cankers on the trunk and the leader with a whitish to orange ooze. EPIDEMIOLOGY Pseudomonas syringae pv. actinidiae can effectively colonize its host plants throughout the year. Bacterial exudates can disperse a large amount of inoculum within and between orchards. In the spring, temperatures ranging from 12 to 18 °C, together with humid conditions, can greatly favour the multiplication of the bacterium, allowing it to systemically move from the leaf to the young shoots. During the summer, very high temperatures can reduce the multiplication and dispersal of the bacterium. Some agronomical techniques, as well as frost, wind, rain and hail storms, can contribute to further spreading. DISEASE CONTROL An integrated approach that takes into consideration precise scheduled spray treatments with effective and environmentally friendly bactericides and equilibrated plant nutrition, coupled with preventive measures aimed at drastically reducing the bacterial inoculum, currently seems to be the possible best solution for coexistence with the disease. The development of resistant cultivars and pollinators, effective biocontrol agents, including bacteriophages, and compounds that induce the systemic activation of plant defence mechanisms is in progress. USEFUL WEBSITES Up-to-date information on bacterial canker research progress and on the spread of the disease in New Zealand can be found at: http://www.kvh.org.nz. Daily information on the spread of the disease and on the research being performed worldwide can be found at: http://www.freshplaza.it.
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Affiliation(s)
- Marco Scortichini
- CRA- Research Centre for Fruit Trees, Via di Fioranello, 52, 00134 Rome, Italy.
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15
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Siefert JL, Souza V, Eguiarte L, Olmedo-Alvarez G. Microbial stowaways: inimitable survivors or hopeless pioneers? ASTROBIOLOGY 2012; 12:710-715. [PMID: 22920519 DOI: 10.1089/ast.2012.0833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The resiliency of prokaryotic life has provided colonization across the globe and in the recesses of Earth's most extreme environments. Horizontal gene transfer provides access to a global bank of genetic resources that creates diversity and allows real-time adaptive potential to the clonal prokaryotic world. We assess the likelihood that this Earth-based strategy could provide survival and adaptive potential, in the case of microbial stowaways off Earth.
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Affiliation(s)
- Janet L Siefert
- Department of Statistics, Rice University, Houston, Texas, USA.
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Raffaele S, Kamoun S. Genome evolution in filamentous plant pathogens: why bigger can be better. Nat Rev Microbiol 2012; 10:417-30. [PMID: 22565130 DOI: 10.1038/nrmicro2790] [Citation(s) in RCA: 452] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many species of fungi and oomycetes are plant pathogens of great economic importance. Over the past 7 years, the genomes of more than 30 of these filamentous plant pathogens have been sequenced, revealing remarkable diversity in genome size and architecture. Whereas the genomes of many parasites and bacterial symbionts have been reduced over time, the genomes of several lineages of filamentous plant pathogens have been shaped by repeat-driven expansions. In these lineages, the genes encoding proteins involved in host interactions are frequently polymorphic and reside within repeat-rich regions of the genome. Here, we review the properties of these adaptable genome regions and the mechanisms underlying their plasticity, and we illustrate cases in which genome plasticity has contributed to the emergence of new virulence traits. We also discuss how genome expansions may have had an impact on the co-evolutionary conflict between these filamentous plant pathogens and their hosts.
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Affiliation(s)
- Sylvain Raffaele
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
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Barrett LG, Heil M. Unifying concepts and mechanisms in the specificity of plant-enemy interactions. TRENDS IN PLANT SCIENCE 2012; 17:282-92. [PMID: 22465042 DOI: 10.1016/j.tplants.2012.02.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 02/13/2012] [Accepted: 02/28/2012] [Indexed: 05/08/2023]
Abstract
Host ranges are commonly quantified to classify herbivores and plant pathogens as either generalists or specialists. Here, we summarize patterns and mechanisms in the interactions of plants with these enemies along different axes of specificity. We highlight the many dimensions within which plant enemies can specify and consider the underlying ecological, evolutionary and molecular mechanisms. Host resistance traits and enemy effectors emerge as central players determining host utilization and thus host range. Finally, we review approaches to studying the causes and consequences of variation in the specificity of plant-enemy interactions. Knowledge of the molecular mechanisms that determine host range is required to understand host shifts, and evolutionary transitions among specialist and generalist strategies, and to predict potential host ranges of pathogens and herbivores.
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Affiliation(s)
- Luke G Barrett
- CSIRO Plant Industry, GPO Box 1600, Canberra ACT, 2601, Australia
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Remigi P, Anisimova M, Guidot A, Genin S, Peeters N. Functional diversification of the GALA type III effector family contributes to Ralstonia solanacearum adaptation on different plant hosts. THE NEW PHYTOLOGIST 2011; 192:976-987. [PMID: 21902695 PMCID: PMC3263339 DOI: 10.1111/j.1469-8137.2011.03854.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 07/09/2011] [Indexed: 05/23/2023]
Abstract
Type III effectors from phytopathogenic bacteria exhibit a high degree of functional redundancy, hampering the evaluation of their precise contribution to pathogenicity. This is illustrated by the GALA type III effectors from Ralstonia solanacearum, which have been shown to be collectively, but not individually, required for disease on Arabidopsis thaliana and tomato. We investigated evolution, redundancy and diversification of this family in order to understand the individual contribution of the GALA effectors to pathogenicity. From sequences available, we reconstructed GALA phylogeny and performed selection studies. We then focused on the GALAs from the reference strain GMI1000 to examine their ability to suppress plant defense responses and contribution to pathogenicity on three different host plants: A. thaliana, tomato (Lycopersicum esculentum) and eggplant (Solanum melongena). The GALA family is well conserved within R. solanacearum species. Patterns of selection detected on some GALA family members, together with experimental results, show that GALAs underwent functional diversification. We conclude that functional divergence of the GALA family likely accounts for its remarkable conservation during R. solanacearum evolution and could contribute to R. solanacearum's adaptation on several host plants.
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Affiliation(s)
- Philippe Remigi
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR441, F-31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR2594, F-31326 Castanet-Tolosan, France
| | - Maria Anisimova
- Department of Computer ScienceETH Zurich, Zurich, Switzerland
- Swiss Institute of BioinformaticsLausanne, Switzerland
| | - Alice Guidot
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR441, F-31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR2594, F-31326 Castanet-Tolosan, France
| | - Stéphane Genin
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR441, F-31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR2594, F-31326 Castanet-Tolosan, France
| | - Nemo Peeters
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR441, F-31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM)UMR2594, F-31326 Castanet-Tolosan, France
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