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Thomas G, Kay WT, Fones HN. Life on a leaf: the epiphyte to pathogen continuum and interplay in the phyllosphere. BMC Biol 2024; 22:168. [PMID: 39113027 PMCID: PMC11304629 DOI: 10.1186/s12915-024-01967-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 08/01/2024] [Indexed: 08/11/2024] Open
Abstract
Epiphytic microbes are those that live for some or all of their life cycle on the surface of plant leaves. Leaf surfaces are a topologically complex, physicochemically heterogeneous habitat that is home to extensive, mixed communities of resident and transient inhabitants from all three domains of life. In this review, we discuss the origins of leaf surface microbes and how different biotic and abiotic factors shape their communities. We discuss the leaf surface as a habitat and microbial adaptations which allow some species to thrive there, with particular emphasis on microbes that occupy the continuum between epiphytic specialists and phytopathogens, groups which have considerable overlap in terms of adapting to the leaf surface and between which a single virulence determinant can move a microbial strain. Finally, we discuss the recent findings that the wheat pathogenic fungus Zymoseptoria tritici spends a considerable amount of time on the leaf surface, and ask what insights other epiphytic organisms might provide into this pathogen, as well as how Z. tritici might serve as a model system for investigating plant-microbe-microbe interactions on the leaf surface.
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Affiliation(s)
| | - William T Kay
- Department of Plant Sciences, University of Oxford, Oxford, UK
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2
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Vadillo‐Dieguez A, Zeng Z, Mansfield JW, Grinberg NF, Lynn SC, Gregg A, Connell J, Harrison RJ, Jackson RW, Hulin MT. Genetic dissection of the tissue-specific roles of type III effectors and phytotoxins in the pathogenicity of Pseudomonas syringae pv. syringae to cherry. MOLECULAR PLANT PATHOLOGY 2024; 25:e13451. [PMID: 38590135 PMCID: PMC11002349 DOI: 10.1111/mpp.13451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024]
Abstract
When compared with other phylogroups (PGs) of the Pseudomonas syringae species complex, P. syringae pv. syringae (Pss) strains within PG2 have a reduced repertoire of type III effectors (T3Es) but produce several phytotoxins. Effectors within the cherry pathogen Pss 9644 were grouped based on their frequency in strains from Prunus as the conserved effector locus (CEL) common to most P. syringae pathogens; a core of effectors common to PG2; a set of PRUNUS effectors common to cherry pathogens; and a FLEXIBLE set of T3Es. Pss 9644 also contains gene clusters for biosynthesis of toxins syringomycin, syringopeptin and syringolin A. After confirmation of virulence gene expression, mutants with a sequential series of T3E and toxin deletions were pathogenicity tested on wood, leaves and fruits of sweet cherry (Prunus avium) and leaves of ornamental cherry (Prunus incisa). The toxins had a key role in disease development in fruits but were less important in leaves and wood. An effectorless mutant retained some pathogenicity to fruit but not wood or leaves. Striking redundancy was observed amongst effector groups. The CEL effectors have important roles during the early stages of leaf infection and possibly acted synergistically with toxins in all tissues. Deletion of separate groups of T3Es had more effect in P. incisa than in P. avium. Mixed inocula were used to complement the toxin mutations in trans and indicated that strain mixtures may be important in the field. Our results highlight the niche-specific role of toxins in P. avium tissues and the complexity of effector redundancy in the pathogen Pss 9644.
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Affiliation(s)
- Andrea Vadillo‐Dieguez
- NIABCambridgeUK
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | | | | | | | | | | | | | - Richard J. Harrison
- NIABCambridgeUK
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
- Faculty of Natural Sciences, Plant Science GroupWageningen University and ResearchWageningenNetherlands
- Present address:
Faculty of Natural Sciences, Plant Science GroupWageningen University and ResearchWageningenNetherlands
| | - Robert W. Jackson
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Michelle T. Hulin
- NIABCambridgeUK
- Department of Plant Soil & Microbial SciencesMichigan State UniversityEast LansingUSA
- Present address:
Department of Plant Soil & Microbial SciencesMichigan State UniversityEast LansingUSA
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3
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Rufián JS, Rueda-Blanco J, Beuzón CR, Ruiz-Albert J. Suppression of NLR-mediated plant immune detection by bacterial pathogens. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6069-6088. [PMID: 37429579 PMCID: PMC10575702 DOI: 10.1093/jxb/erad246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
The plant immune system is constituted of two functionally interdependent branches that provide the plant with an effective defense against microbial pathogens. They can be considered separate since one detects extracellular pathogen-associated molecular patterns by means of receptors on the plant surface, while the other detects pathogen-secreted virulence effectors via intracellular receptors. Plant defense depending on both branches can be effectively suppressed by host-adapted microbial pathogens. In this review we focus on bacterially driven suppression of the latter, known as effector-triggered immunity (ETI) and dependent on diverse NOD-like receptors (NLRs). We examine how some effectors secreted by pathogenic bacteria carrying type III secretion systems can be subject to specific NLR-mediated detection, which can be evaded by the action of additional co-secreted effectors (suppressors), implying that virulence depends on the coordinated action of the whole repertoire of effectors of any given bacterium and their complex epistatic interactions within the plant. We consider how ETI activation can be avoided by using suppressors to directly alter compromised co-secreted effectors, modify plant defense-associated proteins, or occasionally both. We also comment on the potential assembly within the plant cell of multi-protein complexes comprising both bacterial effectors and defense protein targets.
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Affiliation(s)
- José S Rufián
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Depto. Biología Celular, Genética y Fisiología, Málaga, Spain
| | | | - Carmen R Beuzón
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Depto. Biología Celular, Genética y Fisiología, Málaga, Spain
| | - Javier Ruiz-Albert
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Depto. Biología Celular, Genética y Fisiología, Málaga, Spain
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4
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Kvitko BH, Collmer A. Discovery of the Hrp Type III Secretion System in Phytopathogenic Bacteria: How Investigation of Hypersensitive Cell Death in Plants Led to a Novel Protein Injector System and a World of Inter-Organismal Molecular Interactions Within Plant Cells. PHYTOPATHOLOGY 2023; 113:626-636. [PMID: 37099273 DOI: 10.1094/phyto-08-22-0292-kd] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In the early 1960s, Pseudomonas syringae and other host-specific phytopathogenic proteobacteria were discovered to elicit a rapid, resistance-associated death when infiltrated at high inoculum levels into nonhost tobacco leaves. This hypersensitive reaction (or response; HR) was a useful indicator of basic pathogenic ability. Research over the next 20 years failed to identify an elicitor of the HR but revealed that its elicitation required contact between metabolically active bacterial and plant cells. Beginning in the early 1980s, molecular genetic tools were applied to the HR puzzle, revealing the presence in P. syringae of clusters of hrp genes, so named because they are required for the HR and pathogenicity, and of avr genes, so named because their presence confers HR-associated avirulence in resistant cultivars of a host plant species. A series of breakthroughs over the next two decades revealed that (i) hrp gene clusters encode a type III secretion system (T3SS), which injects Avr (now "effector") proteins into plant cells, where their recognition triggers the HR; (ii) T3SSs, which are typically present in pathogenicity islands acquired by horizontal gene transfers, are found in many bacterial pathogens of plants and animals and inject many effector proteins, which are collectively essential for pathogenicity; and (iii) a primary function of phytopathogen effectors is to subvert non-HR defenses resulting from recognition of conserved microbial features presented outside of plant cells. In the 2000s, Hrp system research shifted to extracellular components enabling effector delivery across plant cell walls and plasma membranes, regulation, and tools for studying effectors. [Formula: see text] Copyright © 2023 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)
- Brian H Kvitko
- Department of Plant Pathology, University of Georgia, 120 Carlton St., Athens, GA 30602
| | - Alan Collmer
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, 334 Plant Science Bldg., Ithaca, NY 14853
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Lovelace AH, Dorhmi S, Hulin MT, Li Y, Mansfield JW, Ma W. Effector Identification in Plant Pathogens. PHYTOPATHOLOGY 2023; 113:637-650. [PMID: 37126080 DOI: 10.1094/phyto-09-22-0337-kd] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Effectors play a central role in determining the outcome of plant-pathogen interactions. As key virulence proteins, effectors are collectively indispensable for disease development. By understanding the virulence mechanisms of effectors, fundamental knowledge of microbial pathogenesis and disease resistance have been revealed. Effectors are also considered double-edged swords because some of them activate immunity in disease resistant plants after being recognized by specific immune receptors, which evolved to monitor pathogen presence or activity. Characterization of effector recognition by their cognate immune receptors and the downstream immune signaling pathways is instrumental in implementing resistance. Over the past decades, substantial research effort has focused on effector biology, especially concerning their interactions with virulence targets or immune receptors in plant cells. A foundation of this research is robust identification of the effector repertoire from a given pathogen, which depends heavily on bioinformatic prediction. In this review, we summarize methodologies that have been used for effector mining in various microbial pathogens which use different effector delivery mechanisms. We also discuss current limitations and provide perspectives on how recently developed analytic tools and technologies may facilitate effector identification and hence generation of a more complete vision of host-pathogen interactions. [Formula: see text] Copyright © 2023 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)
| | - Sara Dorhmi
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
- Department of Microbiology and Plant Pathology, University of California Riverside, CA 92521, U.S.A
| | | | - Yufei Li
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
| | - John W Mansfield
- Faculty of Natural Sciences, Imperial College London, London, SW7 2BX, U.K
| | - Wenbo Ma
- The Sainsbury Laboratory, Norwich, NR4 7UH, U.K
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6
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Cooperative virulence via the collective action of secreted pathogen effectors. Nat Microbiol 2023; 8:640-650. [PMID: 36782026 DOI: 10.1038/s41564-023-01328-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 01/13/2023] [Indexed: 02/15/2023]
Abstract
Although virulence is typically attributed to single pathogenic strains, here we investigated whether effectors secreted by a population of non-virulent strains could function as public goods to enable the emergence of collective virulence. We disaggregated the 36 type III effectors of the phytopathogenic bacterium Pseudomonas syringae strain PtoDC3000 into a 'metaclone' of 36 coisogenic strains, each carrying a single effector in an effectorless background. Each coisogenic strain was individually unfit, but the metaclone was collectively as virulent as the wild-type strain on Arabidopsis thaliana, suggesting that effectors can drive the emergence of cooperation-based virulence through their public action. We show that independently evolved effector suits can equally drive this cooperative behaviour by transferring the effector alleles native to the strain PmaES4326 into the conspecific but divergent strain PtoDC3000. Finally, we transferred the disaggregated PtoDC3000 effector arsenal into Pseudomonas fluorescens and show that their cooperative action was sufficient to convert this rhizosphere-inhabiting beneficial bacterium into a phyllosphere pathogen. These results emphasize the importance of microbial community interactions and expand the ecological scale at which disease may be attributed.
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7
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Zhang D, Hu M, Chi S, Chen H, Lin C, Yu F, Zheng Z. Molecular Characteristics and Gonococcal Genetic Island Carrying Status of Thirty-Seven Neisseria gonorrhoeae Isolates in Eastern China. Infect Drug Resist 2022; 15:6545-6553. [DOI: 10.2147/idr.s385079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/27/2022] [Indexed: 11/09/2022] Open
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8
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Metaeffector interactions modulate the type III effector-triggered immunity load of Pseudomonas syringae. PLoS Pathog 2022; 18:e1010541. [PMID: 35576228 PMCID: PMC9135338 DOI: 10.1371/journal.ppat.1010541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/26/2022] [Accepted: 04/21/2022] [Indexed: 11/19/2022] Open
Abstract
The bacterial plant pathogen Pseudomonas syringae requires type III secreted effectors (T3SEs) for pathogenesis. However, a major facet of plant immunity entails the recognition of a subset of P. syringae’s T3SEs by intracellular host receptors in a process called Effector-Triggered Immunity (ETI). Prior work has shown that ETI-eliciting T3SEs are pervasive in the P. syringae species complex raising the question of how P. syringae mitigates its ETI load to become a successful pathogen. While pathogens can evade ETI by T3SE mutation, recombination, or loss, there is increasing evidence that effector-effector (a.k.a., metaeffector) interactions can suppress ETI. To study the ETI-suppression potential of P. syringae T3SE repertoires, we compared the ETI-elicitation profiles of two genetically divergent strains: P. syringae pv. tomato DC3000 (PtoDC3000) and P. syringae pv. maculicola ES4326 (PmaES4326), which are both virulent on Arabidopsis thaliana but harbour largely distinct effector repertoires. Of the 529 T3SE alleles screened on A. thaliana Col-0 from the P. syringae T3SE compendium (PsyTEC), 69 alleles from 21 T3SE families elicited ETI in at least one of the two strain backgrounds, while 50 elicited ETI in both backgrounds, resulting in 19 differential ETI responses including two novel ETI-eliciting families: AvrPto1 and HopT1. Although most of these differences were quantitative, three ETI responses were completely absent in one of the pathogenic backgrounds. We performed ETI suppression screens to test if metaeffector interactions contributed to these ETI differences, and found that HopQ1a suppressed AvrPto1m-mediated ETI, while HopG1c and HopF1g suppressed HopT1b-mediated ETI. Overall, these results show that P. syringae strains leverage metaeffector interactions and ETI suppression to overcome the ETI load associated with their native T3SE repertoires.
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9
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Yuan X, McGhee GC, Slack SM, Sundin GW. A Novel Signaling Pathway Connects Thiamine Biosynthesis, Bacterial Respiration, and Production of the Exopolysaccharide Amylovoran in Erwinia amylovora. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1193-1208. [PMID: 34081536 DOI: 10.1094/mpmi-04-21-0095-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Erwinia amylovora is a plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. This bacterium colonizes host vascular tissues via the production of exopolysaccharides (EPSs) including amylovoran. It is well-established that the nearly ubiquitous plasmid pEA29 of E. amylovora is an essential virulence factor, but the underlying mechanism remains uncharacterized. Here, we demonstrated that pEA29 was required for E. amylovora to produce amylovoran and to form a biofilm, and this regulation was dependent on the thiamine biosynthesis operon thiOSGF. We then conducted carbohydrate and genetic analyses demonstrating that the thiamine-mediated effect on amylovoran production was indirect, as cells lacking thiOSGF produced an EPS that did not contain glucuronic acid, one of the key components of amylovoran, whereas the transcriptional activity and RNA levels of the amylovoran biosynthesis genes were not altered. Alternatively, addition of exogenous thiamine restored amylovoran production in the pEA29-cured strain of E. amylovora and positively impacted amylovoran production in a dose-dependent manner. Individual deletion of several chromosomal thiamine biosynthesis genes also affected amylovoran production, implying that a complete thiamine biosynthesis pathway is required for the thiamine-mediated effect on amylovoran production in E. amylovora. Finally, we determined that an imbalanced tricarboxylic acid cycle negatively affected amylovoran production, which was restored by addition of exogenous thiamine or overexpression of the thiOSGF operon. In summary, our report revealed a novel signaling pathway that impacts E. amylovora virulence in which thiamine biosynthesis enhances bacterial respiration that provides energetic requirements for the biosynthesis of EPS amylovoran.[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)
- Xiaochen Yuan
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Gayle C McGhee
- United States Department of Agriculture, Agriculture Research Service, Horticultural Crops Research Laboratory, Corvallis, OR 97330, U.S.A
| | - Suzanne M Slack
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - George W Sundin
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
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Vaghefi N, Adorada DL, Huth L, Kelly LA, Poudel B, Young A, Sparks AH. Whole-Genome Data from Curtobacterium flaccumfaciens pv. flaccumfaciens Strains Associated with Tan Spot of Mungbean and Soybean Reveal Diverse Plasmid Profiles. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1216-1222. [PMID: 34185567 DOI: 10.1094/mpmi-05-21-0116-a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Despite the substantial economic impact of Curtobacterium flaccumfaciens pv. flaccumfaciens on legume production worldwide, the genetic basis of its pathogenicity and potential host association is poorly understood. The production of high-quality reference genome assemblies of C. flaccumfaciens pv. flaccumfaciens strains associated with different hosts sheds light on the genetic basis of its pathogenic variability and host association. Moreover, the study of recent outbreaks of bacterial wilt and microevolution of the pathogen in Australia requires access to high-quality reference genomes that are sufficiently closely related to the population being studied within Australia. We provide the first genome assemblies of C. flaccumfaciens pv. flaccumfaciens strains associated with mungbean and soybean, which revealed high variability in their plasmid composition. The analysis of C. flaccumfaciens pv. flaccumfaciens genomes revealed an extensive suite of carbohydrate-active enzymes potentially associated with pathogenicity, including four carbohydrate esterases, 50 glycoside hydrolases, 23 glycosyl transferases, and a polysaccharide lyase. We also identified 11 serine peptidases, three of which were located within a linear plasmid, pCff119. These high-quality assemblies and annotations will provide a foundation for population genomics studies of C. flaccumfaciens pv. flaccumfaciens in Australia and for answering fundamental questions regarding pathogenicity factors and adaptation of C. flaccumfaciens pv. flaccumfaciens to various hosts worldwide and, at a broader scale, contribute to unraveling genomic features of gram-positive, xylem-inhabiting bacterial pathogens.[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)
- Niloofar Vaghefi
- Centre for Crop Health, University of Southern Queensland, Australia
| | - Dante L Adorada
- Centre for Crop Health, University of Southern Queensland, Australia
| | - Lauren Huth
- Centre for Crop Health, University of Southern Queensland, Australia
| | - Lisa A Kelly
- Centre for Crop Health, University of Southern Queensland, Australia
- Department of Agriculture and Fisheries, Queensland, Australia
| | - Barsha Poudel
- Centre for Crop Health, University of Southern Queensland, Australia
| | - Anthony Young
- School of Agriculture and Food Sciences, The University of Queensland, Australia
| | - Adam H Sparks
- Centre for Crop Health, University of Southern Queensland, Australia
- Department of Primary Industries and Regional Development, Perth, WA 6983, Australia
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Kumar J, Ramlal A, Kumar K, Rani A, Mishra V. Signaling Pathways and Downstream Effectors of Host Innate Immunity in Plants. Int J Mol Sci 2021; 22:ijms22169022. [PMID: 34445728 PMCID: PMC8396522 DOI: 10.3390/ijms22169022] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/15/2022] Open
Abstract
Phytopathogens, such as biotrophs, hemibiotrophs and necrotrophs, pose serious stress on the development of their host plants, compromising their yields. Plants are in constant interaction with such phytopathogens and hence are vulnerable to their attack. In order to counter these attacks, plants need to develop immunity against them. Consequently, plants have developed strategies of recognizing and countering pathogenesis through pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Pathogen perception and surveillance is mediated through receptor proteins that trigger signal transduction, initiated in the cytoplasm or at the plasma membrane (PM) surfaces. Plant hosts possess microbe-associated molecular patterns (P/MAMPs), which trigger a complex set of mechanisms through the pattern recognition receptors (PRRs) and resistance (R) genes. These interactions lead to the stimulation of cytoplasmic kinases by many phosphorylating proteins that may also be transcription factors. Furthermore, phytohormones, such as salicylic acid, jasmonic acid and ethylene, are also effective in triggering defense responses. Closure of stomata, limiting the transfer of nutrients through apoplast and symplastic movements, production of antimicrobial compounds, programmed cell death (PCD) are some of the primary defense-related mechanisms. The current article highlights the molecular processes involved in plant innate immunity (PII) and discusses the most recent and plausible scientific interventions that could be useful in augmenting PII.
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Affiliation(s)
- Jitendra Kumar
- Bangalore Bioinnovation Centre, Life Sciences Park, Electronics City Phase 1, Bengaluru 560100, India;
| | - Ayyagari Ramlal
- Division of Genetics, Indian Agricultural Research Institute (IARI), Pusa Campus, New Delhi 110012, India;
| | - Kamal Kumar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110066, India;
| | - Anita Rani
- Department of Botany, Dyal Singh College, University of Delhi, Delhi 110003, India;
| | - Vachaspati Mishra
- Department of Botany, Dyal Singh College, University of Delhi, Delhi 110003, India;
- Correspondence:
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12
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Luo D, Huguet-Tapia JC, Raborn RT, White FF, Brendel VP, Yang B. The Xa7 resistance gene guards the rice susceptibility gene SWEET14 against exploitation by the bacterial blight pathogen. PLANT COMMUNICATIONS 2021; 2:100164. [PMID: 34027391 PMCID: PMC8132128 DOI: 10.1016/j.xplc.2021.100164] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 05/03/2023]
Abstract
Many plant disease resistance (R) genes function specifically in reaction to the presence of cognate effectors from a pathogen. Xanthomonas oryzae pathovar oryzae (Xoo) uses transcription activator-like effectors (TALes) to target specific rice genes for expression, thereby promoting host susceptibility to bacterial blight. Here, we report the molecular characterization of Xa7, the cognate R gene to the TALes AvrXa7 and PthXo3, which target the rice major susceptibility gene SWEET14. Xa7 was mapped to a unique 74-kb region. Gene expression analysis of the region revealed a candidate gene that contained a putative AvrXa7 effector binding element (EBE) in its promoter and encoded a 113-amino-acid peptide of unknown function. Genome editing at the Xa7 locus rendered the plants susceptible to avrXa7-carrying Xoo strains. Both AvrXa7 and PthXo3 activated a GUS reporter gene fused with the EBE-containing Xa7 promoter in Nicotiana benthamiana. The EBE of Xa7 is a close mimic of the EBE of SWEET14 for TALe-induced disease susceptibility. Ectopic expression of Xa7 triggers cell death in N. benthamiana. Xa7 is prevalent in indica rice accessions from 3000 rice genomes. Xa7 appears to be an adaptation that protects against pathogen exploitation of SWEET14 and disease susceptibility.
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Affiliation(s)
- Dangping Luo
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Jose C. Huguet-Tapia
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - R. Taylor Raborn
- Department of Biology, Department of Computer Science, Indiana University, Bloomington, IN 47405, USA
- Current address: Biodesign Institute Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281, USA
| | - Frank F. White
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Volker P. Brendel
- Department of Biology, Department of Computer Science, Indiana University, Bloomington, IN 47405, USA
| | - Bing Yang
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Corresponding author
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Xu X, Xu Z, Ma W, Haq F, Li Y, Shah SMA, Zhu B, Zhu C, Zou L, Chen G. TALE-triggered and iTALE-suppressed Xa1-mediated resistance to bacterial blight is independent of rice transcription factor subunits OsTFIIAγ1 or OsTFIIAγ5. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3249-3262. [PMID: 33544818 DOI: 10.1093/jxb/erab054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Xa1-mediated resistance to rice bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is triggered by transcription activator-like effectors (TALEs) and suppressed by interfering TALEs (iTALEs). TALEs interact with the rice transcription factor OsTFIIAγ1 or OsTFIIAγ5 (Xa5) to activate expression of target resistance and/or susceptibility genes. However, it is not clear whether OsTFIIAγ is involved in TALE-triggered and iTALE-suppressed Xa1-mediated resistance. In this study, genome-edited mutations in OsTFIIAγ5 or OsTFIIAγ1 of Xa1-containing rice 'IRBB1' and Xa1-transgenic plants of xa5-containing rice 'IRBB5' did not impair the activation or suppression of Xa1-mediated resistance. Correspondingly, the expression pattern of Xa1 in mutated OsTFIIAγ5 and OsTFIIAγ1 rice lines and 'IRBB1' rice was similar. In contrast, the expression of OsSWEET11 was repressed in rice lines mutated in OsTFIIAγ5 and OsTFIIAγ1. Bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation assays showed that both TALE PthXo1 and iTALE Tal3a interacted with OsTFIIAγ1 and OsTFIIAγ5 in plant nuclei. These results indicated that TALE-triggered and iTALE-suppressed Xa1-mediated resistance to bacterial blight is independent of OsTFIIAγ1 or OsTFIIAγ5 in rice, and suggest that an unknown factor is potentially involved in the interaction of Xa1, TALEs and iTALEs.
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Affiliation(s)
- Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Li
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Zhu
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Changxiang Zhu
- National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China
| | - Lifang Zou
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai, China
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A Large Tn7-like Transposon Confers Hyper-Resistance to Copper in Pseudomonas syringae pv. syringae. Appl Environ Microbiol 2021; 87:AEM.02528-20. [PMID: 33361370 PMCID: PMC8090865 DOI: 10.1128/aem.02528-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Copper resistance mechanisms provide an important adaptive advantage to plant pathogenic bacteria under exposure to copper treatments. Copper resistance determinants have been described in Pseudomonas syringae pv. syringae (Pss) strains isolated from mango intimately associated with 62 kb plasmids belonging to the pPT23A family (PFP). It has been previously described that the indiscriminate use of copper-based compounds promotes the selection of copper resistant bacterial strains and constitutes a selective pressure in the evolution of copper resistance determinants. Hence, we have explored in this study the copper resistance evolution and the distribution of specific genetic determinants in two different Pss mango populations isolated from the same geographical regions, mainly from southern Spain with an average of 20 years of difference. The total content of plasmids, in particular the 62 kb plasmids, and the number of copper resistant Pss strains were maintained at similar levels over the time. Interestingly, the phylogenetic analysis indicated the presence of a phylogenetic subgroup (PSG) in the Pss mango phylotype, mostly composed of the recent Pss population analyzed in this study that was strongly associated with a hyper-resistant phenotype to copper. Genome sequencing of two selected Pss strains from this PSG revealed the presence of a large Tn7-like transposon of chromosomal location, which harbored putative copper and arsenic resistance genes (COARS Tn7-like). Transformation of the copper sensitive Pss UMAF0158 strain with some putative copper resistance genes and RT-qPCR experiments brought into light the role of COARS Tn7-like transposon in the hyper-resistant phenotype to copper in Pss.IMPORTANCECopper compounds have traditionally been used as standard bactericides in agriculture in the past few decades. However, the extensive use of copper has fostered the evolution of bacterial copper resistance mechanisms. Pseudomonas syringae is a plant pathogenic bacterium used worldwide as a model to study plant-pathogen interactions. The adaption of P. syringae to plant surface environment is the most important step prior to an infection. In this scenario, copper resistance mechanisms could play a key role in improving its epiphytic survival. In this work, a novel Tn7-like transposon of chromosomal location was detected in P. syringae pv. syringae strains isolated from mango. This transposon conferred the highest resistance to copper sulfate described to date for this bacterial phytopathogen. Understanding in depth the copper resistance mechanisms and their evolution are important steps to the agricultural industry to get a better improvement of disease management strategies.
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Van Rossum T, Ferretti P, Maistrenko OM, Bork P. Diversity within species: interpreting strains in microbiomes. Nat Rev Microbiol 2020; 18:491-506. [PMID: 32499497 PMCID: PMC7610499 DOI: 10.1038/s41579-020-0368-1] [Citation(s) in RCA: 178] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2020] [Indexed: 02/06/2023]
Abstract
Studying within-species variation has traditionally been limited to culturable bacterial isolates and low-resolution microbial community fingerprinting. Metagenomic sequencing and technical advances have enabled culture-free, high-resolution strain and subspecies analyses at high throughput and in complex environments. This holds great scientific promise but has also led to an overwhelming number of methods and terms to describe infraspecific variation. This Review aims to clarify these advances by focusing on the diversity within bacterial and archaeal species in the context of microbiomics. We cover foundational microevolutionary concepts relevant to population genetics and summarize how within-species variation can be studied and stratified directly within microbial communities with a focus on metagenomics. Finally, we describe how common applications of within-species variation can be achieved using metagenomic data. We aim to guide the selection of appropriate terms and analytical approaches to facilitate researchers in benefiting from the increasing availability of large, high-resolution microbiome genetic sequencing data.
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Affiliation(s)
- Thea Van Rossum
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Pamela Ferretti
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Oleksandr M Maistrenko
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Peer Bork
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany.
- Max Delbrück Centre for Molecular Medicine, Berlin, Germany.
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany.
- Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany.
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Añorga M, Pintado A, Ramos C, De Diego N, Ugena L, Novák O, Murillo J. Genes ptz and idi, Coding for Cytokinin Biosynthesis Enzymes, Are Essential for Tumorigenesis and In Planta Growth by P. syringae pv. savastanoi NCPPB 3335. FRONTIERS IN PLANT SCIENCE 2020; 11:1294. [PMID: 32973852 PMCID: PMC7472798 DOI: 10.3389/fpls.2020.01294] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
The phytopathogenic bacterium Pseudomonas syringae pv. savastanoi elicits aerial tumors on olive plants and is also able to synthesize large amounts of auxins and cytokinins. The auxin indoleacetic acid was shown to be required for tumorigenesis, but there is only correlational evidence suggesting a role for cytokinins. The model strain NCPPB 3335 contains two plasmid-borne genes coding for cytokinin biosynthesis enzymes: ptz, for an isopentenyl transferase and idi, for an isopentenyl-diphosphate delta-isomerase. Phylogenetic analyses showed that carriage of ptz and idi is not strictly associated with tumorigenic bacteria, that both genes were linked when first acquired by P. syringae, and that a different allele of ptz has been independently acquired by P. syringae pv. savastanoi and closely related bacteria. We generated mutant derivatives of NCPPB 3335 cured of virulence plasmids or with site-specific deletions of genes ptz and/or idi and evaluated their virulence in lignified and micropropagated olive plants. Strains lacking ptz, idi, or both produced tumors with average volumes up to 29 times smaller and reached populations up to two orders of magnitude lower than those induced by strain NCPPB 3335; these phenotypes reverted by complementation with the cloned genes. Trans-zeatin was the most abundant cytokinin in culture filtrates of NCPPB 3335. Deletion of gene ptz abolished biosynthesis of trans-zeatin and dihydrozeatin, whereas a reduced but significant amount of isopentenyladenine was still detected in the medium, suggesting the existence of other genes contributing to cytokinin biosynthesis in P. syringae. Conversely, extracts from strains lacking gene idi contained significantly higher amounts of trans-zeatin than extracts from the wild-type strain but similar amounts of the other cytokinins. This suggests that Idi might promote tumorigenesis by ensuring the biosynthesis of the most active cytokinin forms, their correct balance in planta, or by regulating the expression of other virulence genes. Therefore, gene ptz, but not gene idi, is essential for the biosynthesis of high amounts of cytokinins in culture; however, both ptz and idi are individually essential for the adequate development of tumors on olive plants by Psv NCPPB 3335.
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Affiliation(s)
- Maite Añorga
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, Mutilva Baja, Spain
| | - Adrián Pintado
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, Spain
| | - Nuria De Diego
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Lydia Ugena
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Ondřej Novák
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
- Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, Czechia
| | - Jesús Murillo
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, Mutilva Baja, Spain
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Hulin MT, Jackson RW, Harrison RJ, Mansfield JW. Cherry picking by pseudomonads: After a century of research on canker, genomics provides insights into the evolution of pathogenicity towards stone fruits. PLANT PATHOLOGY 2020; 69:962-978. [PMID: 32742023 PMCID: PMC7386918 DOI: 10.1111/ppa.13189] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/09/2020] [Accepted: 03/23/2020] [Indexed: 05/10/2023]
Abstract
Bacterial canker disease is a major limiting factor in the growing of cherry and other Prunus species worldwide. At least five distinct clades within the bacterial species complex Pseudomonas syringae are known to be causal agents of the disease. The different pathogens commonly coexist in the field. Reducing canker is a challenging prospect as the efficacy of chemical controls and host resistance may vary against each of the diverse clades involved. Genomic analysis has revealed that the pathogens use a variable repertoire of virulence factors to cause the disease. Significantly, strains of P. syringae pv. syringae possess more genes for toxin biosynthesis and fewer encoding type III effector proteins. There is also a shared pool of key effector genes present on mobile elements such as plasmids and prophages that may have roles in virulence. By contrast, there is evidence that absence or truncation of certain effector genes, such as hopAB, is characteristic of cherry pathogens. Here we highlight how recent research, underpinned by the earlier epidemiological studies, is allowing significant progress in our understanding of the canker pathogens. This fundamental knowledge, combined with emerging insights into host genetics, provides the groundwork for development of precise control measures and informed approaches to breed for disease resistance.
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Affiliation(s)
| | - Robert W. Jackson
- Birmingham Institute of Forest Research (BIFoR), University of BirminghamBirminghamUK
- School of Biosciences, University of BirminghamBirminghamUK
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Ji C, Ji Z, Liu B, Cheng H, Liu H, Liu S, Yang B, Chen G. Xa1 Allelic R Genes Activate Rice Blight Resistance Suppressed by Interfering TAL Effectors. PLANT COMMUNICATIONS 2020; 1:100087. [PMID: 33367250 PMCID: PMC7748017 DOI: 10.1016/j.xplc.2020.100087] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 05/03/2023]
Abstract
Xanthomonas oryzae pathovar oryzae (Xoo) uses transcription activator-like effectors (TALEs) to cause bacterial blight (BB) in rice. In turn, rice has evolved several mechanisms to resist BB by targeting TALEs. One mechanism involves the nucleotide-binding leucine-rich repeat (NLR) resistance gene Xa1 and TALEs. Reciprocally, Xoo has evolved TALE variants, C-terminally truncated versions (interfering TALEs or iTALEs), to overcome Xa1 resistance. However, it remains unknown to what extent the two co-adaptive mechanisms mediate Xoo-rice interactions. In this study, we cloned and characterized five additional Xa1 allelic R genes, Xa2, Xa31(t), Xa14, CGS-Xo111 , and Xa45(t) from a collection of rice accessions. Sequence analysis revealed that Xa2 and Xa31(t) from different rice cultivars are identical. These genes and their predicted proteins were found to be highly conserved, forming a group of Xa1 alleles. The XA1 alleles could be distinguished by the number of C-terminal tandem repeats consisting of 93 amino acid residues and ranged from four in XA14 to seven in XA45(t). Xa1 allelic genes were identified in the 3000 rice genomes surveyed. On the other hand, iTALEs could suppress the resistance mediated by Xa1 allelic R genes, and iTALE genes were prevalent (∼95%) in Asian, but not in African Xoo strains. Our findings demonstrate the prominence of a defense mechanism in which rice depends on Xa1 alleles and a counteracting mechanism in which Xoo relies on iTALEs for BB.
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Affiliation(s)
- Chonghui Ji
- Division of Plant Sciences, C. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Zhiyuan Ji
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, P.R. China
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China
| | - Bo Liu
- Division of Plant Sciences, C. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - He Cheng
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Hua Liu
- Division of Plant Sciences, C. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Bing Yang
- Division of Plant Sciences, C. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Corresponding author
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, P.R. China
- Corresponding author
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Hwang IS, Lee HM, Oh E, Lee S, Heu S, Oh C. Plasmid composition and the chpG gene determine the virulence level of Clavibacter capsici natural isolates in pepper. MOLECULAR PLANT PATHOLOGY 2020; 21:808-819. [PMID: 32196887 PMCID: PMC7214350 DOI: 10.1111/mpp.12932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 05/23/2023]
Abstract
The gram-positive bacterial species Clavibacter capsici causes necrosis and canker in pepper plants. Genomic and functional analyses of C. capsici type strain PF008 have shown that multiple virulence genes exist in its two plasmids. We aimed to identify the key determinants that control the virulence of C. capsici. Pepper leaves inoculated with 54 natural isolates exhibited significant variation in the necrosis. Six isolates showed very low virulence, but their population titres in plants were not significantly different from those of the highly virulent isolates. All six isolates lacked the pCM1Cc plasmid that carries chpG, which has been shown to be required for virulence and encodes a putative serine protease, but two of them, isolates 1,106 and 1,207, had the intact chpG elsewhere in the genome. Genomic analysis of these two isolates revealed that chpG was located in the pCM2Cc plasmid, and two highly homologous regions were present next to the chpG locus. The chpG expression in isolate 1,106 was not induced in plants. Introduction of chpG of the PF008 strain into the six low-virulence isolates restored their virulence to that of PF008. Our findings indicate that there are at least three different variant groups of C. capsici and that the plasmid composition and the chpG gene are critical for determining the virulence level. Moreover, our findings also indicate that the virulence level of C. capsici does not directly correlate with bacterial titres in plants.
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Affiliation(s)
- In Sun Hwang
- Department of Horticultural BiotechnologyCollege of Life SciencesKyung Hee UniversityYonginSouth Korea
| | - Hyo Min Lee
- Department of Horticultural BiotechnologyCollege of Life SciencesKyung Hee UniversityYonginSouth Korea
| | - Eom‐Ji Oh
- Department of Horticultural BiotechnologyCollege of Life SciencesKyung Hee UniversityYonginSouth Korea
| | - Seungdon Lee
- Planning and Coordination DivisionNational Institute of Agricultural SciencesRural Development AdministrationWanjuSouth Korea
| | - Sunggi Heu
- Crop Cultivation and Environment Research DivisionNational Institute of Crop ScienceRural Development AdministrationSuwonSouth Korea
| | - Chang‐Sik Oh
- Department of Horticultural BiotechnologyCollege of Life SciencesKyung Hee UniversityYonginSouth Korea
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20
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Collmer A. James Robert Alfano, A Giant in Phytopathogenic Bacteria Effector Biology. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:377-381. [PMID: 31990622 DOI: 10.1094/mpmi-12-19-0354-cr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The worldwide molecular plant-microbe interactions research community was significantly diminished in November 2019 by the death of James "Jim" Robert Alfano at age 56. Jim was a giant in our field, who gained key insights into plant pathogenesis using the model bacterial pathogen Pseudomonas syringae. As a mentor, collaborator, and, above all, a friend, I know Jim's many dimensions and accomplishments and, sadly, the depth of loss being felt by the many people around the world who were touched by him. In tracing the path of Jim's career, I will emphasize the historical context and impact of his advances and, finally, the essence of the person we will so miss.
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Affiliation(s)
- Alan Collmer
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, U.S.A
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21
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Gutiérrez-Barranquero JA, Cazorla FM, de Vicente A. Pseudomonas syringae pv. syringae Associated With Mango Trees, a Particular Pathogen Within the "Hodgepodge" of the Pseudomonas syringae Complex. FRONTIERS IN PLANT SCIENCE 2019; 10:570. [PMID: 31139201 PMCID: PMC6518948 DOI: 10.3389/fpls.2019.00570] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/15/2019] [Indexed: 05/29/2023]
Abstract
The Pseudomonas syringae complex comprises different genetic groups that include strains from both agricultural and environmental habitats. This complex group has been used for decades as a "hodgepodge," including many taxonomically related species. More than 60 pathovars of P. syringae have been described based on distinct host ranges and disease symptoms they cause. These pathovars cause disease relying on an array of virulence mechanisms. However, P. syringae pv. syringae (Pss) is the most polyphagous bacterium in the P. syringae complex, based on its wide host range, that primarily affects woody and herbaceous host plants. In early 1990s, bacterial apical necrosis (BAN) of mango trees, a critical disease elicited by Pss in Southern Spain was described for the first time. Pss exhibits important epiphytic traits and virulence factors, which may promote its survival and pathogenicity in mango trees and in other plant hosts. Over more than two decades, Pss strains isolated from mango trees have been comprehensively investigated to elucidate the mechanisms that governs their epiphytic and pathogenic lifestyles. In particular, the vast majority of Pss strains isolated from mango trees produce an antimetabolite toxin, called mangotoxin, whose leading role in virulence has been clearly demonstrated. Moreover, phenotypic, genetic and phylogenetic approaches support that Pss strains producers of BAN symptoms on mango trees all belong to a single phylotype within phylogroup 2, are adapted to the mango host, and produce mangotoxin. Remarkably, a genome sequencing project of the Pss model strain UMAF0158 revealed the presence of other factors that may play major roles in its different lifestyles, such as the presence of two different type III secretion systems, two type VI secretion systems and an operon for cellulose biosynthesis. The role of cellulose in increasing mango leaf colonization and biofilm formation, and impairing virulence of Pss, suggests that cellulose may play a pivotal role with regards to the balance of its different lifestyles. In addition, 62-kb plasmids belonging to the pPT23A-family of plasmids (PFPs) have been strongly associated with Pss strains that inhabit mango trees. Further, complete sequence and comparative genomic analyses revealed major roles of PFPs in detoxification of copper compounds and ultraviolet radiation resistance, both improving the epiphytic lifestyle of Pss on mango surfaces. Hence, in this review we summarize the research that has been conducted on Pss by our research group to elucidate the molecular mechanisms that underpin the epiphytic and pathogenic lifestyle on mango trees. Finally, future directions in this particular plant-pathogen story are discussed.
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22
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Khachatryan L, Kraakman MEM, Bernards AT, Laros JFJ. BacTag - a pipeline for fast and accurate gene and allele typing in bacterial sequencing data based on database preprocessing. BMC Genomics 2019; 20:338. [PMID: 31060512 PMCID: PMC6501397 DOI: 10.1186/s12864-019-5723-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 04/22/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Bacteria carry a wide array of genes, some of which have multiple alleles. These different alleles are often responsible for distinct types of virulence and can determine the classification at the subspecies levels (e.g., housekeeping genes for Multi Locus Sequence Typing, MLST). Therefore, it is important to rapidly detect not only the gene of interest, but also the relevant allele. Current sequencing-based methods are limited to mapping reads to each of the known allele reference, which is a time-consuming procedure. RESULTS To address this limitation, we developed BacTag - a pipeline that rapidly and accurately detects which genes are present in a sequencing dataset and reports the allele of each of the identified genes. We exploit the fact that different alleles of the same gene have a high similarity. Instead of mapping the reads to each of the allele reference sequences, we preprocess the database prior to the analysis, which makes the subsequent gene and allele identification efficient. During the preprocessing, we determine a representative reference sequence for each gene and store the differences between all alleles and this chosen reference. Throughout the analysis we estimate whether the gene is present in the sequencing data by mapping the reads to this reference sequence; if the gene is found, we compare the variants to those in the preprocessed database. This allows to detect which specific allele is present in the sequencing data. Our pipeline was successfully tested on artificial WGS E. coli, S. pseudintermedius, P. gingivalis, M. bovis, Borrelia spp. and Streptomyces spp. data and real WGS E. coli and K. pneumoniae data in order to report alleles of MLST house-keeping genes. CONCLUSIONS We developed a new pipeline for fast and accurate gene and allele recognition based on database preprocessing and parallel computing and performed better or comparable to the current popular tools. We believe that our approach can be useful for a wide range of projects, including bacterial subspecies classification, clinical diagnostics of bacterial infections, and epidemiological studies.
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Affiliation(s)
- Lusine Khachatryan
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Margriet E M Kraakman
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Alexandra T Bernards
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeroen F J Laros
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands.,GenomeScan, Leiden, The Netherlands
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An improved plasmid size standard, 39R861+. Plasmid 2019; 102:6-9. [DOI: 10.1016/j.plasmid.2019.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 11/23/2022]
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Figaj D, Ambroziak P, Przepiora T, Skorko-Glonek J. The Role of Proteases in the Virulence of Plant Pathogenic Bacteria. Int J Mol Sci 2019; 20:ijms20030672. [PMID: 30720762 PMCID: PMC6386880 DOI: 10.3390/ijms20030672] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/30/2019] [Accepted: 02/02/2019] [Indexed: 12/17/2022] Open
Abstract
A pathogenic lifestyle is inextricably linked with the constant necessity of facing various challenges exerted by the external environment (both within and outside the host). To successfully colonize the host and establish infection, pathogens have evolved sophisticated systems to combat the host defense mechanisms and also to be able to withstand adverse environmental conditions. Proteases, as crucial components of these systems, are involved in a variety of processes associated with infection. In phytopathogenic bacteria, they play important regulatory roles and modulate the expression and functioning of various virulence factors. Secretory proteases directly help avoid recognition by the plant immune systems, and contribute to the deactivation of the defense response pathways. Finally, proteases are important components of protein quality control systems, and thus enable maintaining homeostasis in stressed bacterial cells. In this review, we discuss the known protease functions and protease-regulated signaling processes associated with virulence of plant pathogenic bacteria.
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Affiliation(s)
- Donata Figaj
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
| | - Patrycja Ambroziak
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
| | - Tomasz Przepiora
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
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Bardaji L, Añorga M, Echeverría M, Ramos C, Murillo J. The toxic guardians - multiple toxin-antitoxin systems provide stability, avoid deletions and maintain virulence genes of Pseudomonas syringae virulence plasmids. Mob DNA 2019; 10:7. [PMID: 30728866 PMCID: PMC6354349 DOI: 10.1186/s13100-019-0149-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/18/2019] [Indexed: 02/05/2023] Open
Abstract
Background Pseudomonas syringae is a γ-proteobacterium causing economically relevant diseases in practically all cultivated plants. Most isolates of this pathogen contain native plasmids collectively carrying many pathogenicity and virulence genes. However, P. syringae is generally an opportunistic pathogen primarily inhabiting environmental reservoirs, which could exert a low selective pressure for virulence plasmids. Additionally, these plasmids usually contain a large proportion of repeated sequences, which could compromise plasmid integrity. Therefore, the identification of plasmid stability determinants and mechanisms to preserve virulence genes is essential to understand the evolution of this pathogen and its adaptability to agroecosystems. Results The three virulence plasmids of P. syringae pv. savastanoi NCPPB 3335 contain from one to seven functional stability determinants, including three highly active toxin-antitoxin systems (TA) in both pPsv48A and pPsv48C. The TA systems reduced loss frequency of pPsv48A by two orders of magnitude, whereas one of the two replicons of pPsv48C likely confers stable inheritance by itself. Notably, inactivation of the TA systems from pPsv48C exposed the plasmid to high-frequency deletions promoted by mobile genetic elements. Thus, recombination between two copies of MITEPsy2 caused the deletion of an 8.3 kb fragment, with a frequency of 3.8 ± 0.3 × 10− 3. Likewise, one-ended transposition of IS801 generated plasmids containing deletions of variable size, with a frequency of 5.5 ± 2.1 × 10− 4, of which 80% had lost virulence gene idi. These deletion derivatives were stably maintained in the population by replication mediated by repJ, which is adjacent to IS801. IS801 also promoted deletions in plasmid pPsv48A, either by recombination or one-ended transposition. In all cases, functional TA systems contributed significantly to reduce the occurrence of plasmid deletions in vivo. Conclusions Virulence plasmids from P. syringae harbour a diverse array of stability determinants with a variable contribution to plasmid persistence. Importantly, we showed that multiple plasmid-borne TA systems have a prominent role in preserving plasmid integrity and ensuring the maintenance of virulence genes in free-living conditions. This strategy is likely widespread amongst native plasmids of P. syringae and other bacteria. Electronic supplementary material The online version of this article (10.1186/s13100-019-0149-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leire Bardaji
- 1Institute for Multidisciplinary Applied Biology, Universidad Pública de Navarra, 31192 Mutilva, Spain
| | - Maite Añorga
- 1Institute for Multidisciplinary Applied Biology, Universidad Pública de Navarra, 31192 Mutilva, Spain
| | - Myriam Echeverría
- 1Institute for Multidisciplinary Applied Biology, Universidad Pública de Navarra, 31192 Mutilva, Spain
| | - Cayo Ramos
- 2Instituto de Hortofruticultura Subtropical y Mediterránea «La Mayora», Universidad de Málaga-CSIC, Área de Genética, Universidad de Málaga, Campus de Teatinos s/n, 29010 Málaga, Spain
| | - Jesús Murillo
- 1Institute for Multidisciplinary Applied Biology, Universidad Pública de Navarra, 31192 Mutilva, Spain
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Leisner SM, Schoelz JE. Joining the Crowd: Integrating Plant Virus Proteins into the Larger World of Pathogen Effectors. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:89-110. [PMID: 29852091 DOI: 10.1146/annurev-phyto-080417-050151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The first bacterial and viral avirulence ( avr) genes were cloned in 1984. Although virus and bacterial avr genes were physically isolated in the same year, the questions associated with their characterization after discovery were very different, and these differences had a profound influence on the narrative of host-pathogen interactions for the past 30 years. Bacterial avr proteins were subsequently shown to suppress host defenses, leading to their reclassification as effectors, whereas research on viral avr proteins centered on their role in the viral infection cycle rather than their effect on host defenses. Recent studies that focus on the multifunctional nature of plant virus proteins have shown that some virus proteins are capable of suppression of the same host defenses as bacterial effectors. This is exemplified by the P6 protein of Cauliflower mosaic virus (CaMV), a multifunctional plant virus protein that facilitates several steps in the infection, including modulation of host defenses. This review highlights the modular structure and multifunctional nature of CaMV P6 and illustrates its similarities to other, well-established pathogen effectors.
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Affiliation(s)
- Scott M Leisner
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606, USA
| | - James E Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211, USA;
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27
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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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28
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Gimenez-Ibanez S, Hann DR, Chang JH, Segonzac C, Boller T, Rathjen JP. Differential Suppression of Nicotiana benthamiana Innate Immune Responses by Transiently Expressed Pseudomonas syringae Type III Effectors. FRONTIERS IN PLANT SCIENCE 2018; 9:688. [PMID: 29875790 PMCID: PMC5974120 DOI: 10.3389/fpls.2018.00688] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/04/2018] [Indexed: 05/13/2023]
Abstract
The plant pathogen Pseudomonas syringae injects about 30 different virulence proteins, so-called effectors, via a type III secretion system into plant cells to promote disease. Although some of these effectors are known to suppress either pattern-triggered immunity (PTI) or effector-triggered immunity (ETI), the mode of action of most of them remains unknown. Here, we used transient expression in Nicotiana benthamiana, to test the abilities of type III effectors of Pseudomonas syringae pv. tomato (Pto) DC3000 and Pseudomonas syringae pv. tabaci (Pta) 11528 to interfere with plant immunity. We monitored the sequential and rapid bursts of cytoplasmic Ca2+ and reactive oxygen species (ROS), the subsequent induction of defense gene expression, and promotion of cell death. We found that several effector proteins caused cell death, but independently of the known plant immune regulator NbSGT1, a gene essential for ETI. Furthermore, many effectors delayed or blocked the cell death-promoting activity of other effectors, thereby potentially contributing to pathogenesis. Secondly, a large number of effectors were able to suppress PAMP-induced defense responses. In the majority of cases, this resulted in suppression of all studied PAMP responses, suggesting that these effectors target common elements of PTI. However, effectors also targeted different steps within defense pathways and could be divided into three major groups based on their suppressive activities. Finally, the abilities of effectors of both Pto DC3000 and Pta 11528 to suppress plant immunity was conserved in most but not all cases. Overall, our data present a comprehensive picture of the mode of action of these effectors and indicate that most of them suppress plant defenses in various ways.
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Affiliation(s)
- Selena Gimenez-Ibanez
- The Sainsbury Laboratory, Norwich, United Kingdom
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Dagmar R Hann
- The Sainsbury Laboratory, Norwich, United Kingdom
- Department of Environmental Sciences, Botanical Institute, University of Basel, Basel, Switzerland
- Institute of Genetics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, United States
| | - Cécile Segonzac
- The Sainsbury Laboratory, Norwich, United Kingdom
- Department of Plant Science, Plant Genomics and Breeding Institute and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Thomas Boller
- Department of Environmental Sciences, Botanical Institute, University of Basel, Basel, Switzerland
| | - John P Rathjen
- The Sainsbury Laboratory, Norwich, United Kingdom
- Research School of Biology, Australian National University, Acton, ACT, Australia
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Dorati F, Barrett GA, Sanchez-Contreras M, Arseneault T, José MS, Studholme DJ, Murillo J, Caballero P, Waterfield NR, Arnold DL, Shaw LJ, Jackson RW. Coping with Environmental Eukaryotes; Identification of Pseudomonas syringae Genes during the Interaction with Alternative Hosts or Predators. Microorganisms 2018; 6:microorganisms6020032. [PMID: 29690522 PMCID: PMC6027264 DOI: 10.3390/microorganisms6020032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/09/2018] [Accepted: 04/20/2018] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms underpinning the ecological success of plant pathogens is critical to develop strategies for controlling diseases and protecting crops. Recent observations have shown that plant pathogenic bacteria, particularly Pseudomonas, exist in a range of natural environments away from their natural plant host e.g., water courses, soil, non-host plants. This exposes them to a variety of eukaryotic predators such as nematodes, insects and amoebae present in the environment. Nematodes and amoeba in particular are bacterial predators while insect herbivores may act as indirect predators, ingesting bacteria on plant tissue. We therefore postulated that bacteria are probably under selective pressure to avoid or survive predation and have therefore developed appropriate coping mechanisms. We tested the hypothesis that plant pathogenic Pseudomonas syringae are able to cope with predation pressure and found that three pathovars show weak, but significant resistance or toxicity. To identify the gene systems that contribute to resistance or toxicity we applied a heterologous screening technique, called Rapid Virulence Annotation (RVA), for anti-predation and toxicity mechanisms. Three cosmid libraries for P. syringae pv. aesculi, pv. tomato and pv. phaseolicola, of approximately 2000 cosmids each, were screened in the susceptible/non-toxic bacterium Escherichia coli against nematode, amoebae and an insect. A number of potential conserved and unique genes were identified which included genes encoding haemolysins, biofilm formation, motility and adhesion. These data provide the first multi-pathovar comparative insight to how plant pathogens cope with different predation pressures and infection of an insect gut and provide a foundation for further study into the function of selected genes and their role in ecological success.
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Affiliation(s)
- Federico Dorati
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | - Glyn A Barrett
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | | | - Tanya Arseneault
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, Research and Development Centre, Quebec, J3B 3E6, Canada.
| | - Mateo San José
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | | | - Jesús Murillo
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, 31192 Mutilva, Spain.
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, 31192 Mutilva, Spain.
| | - Nicholas R Waterfield
- Department of Biology and Biochemistry, University of Bath, Bath, BA1 9BJ, UK.
- Warwick Medical School, University of Warwick, Warwick, CV4 7AL, UK.
| | - Dawn L Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK.
| | - Liz J Shaw
- School of Archaeology, Geography and Environmental Science, University of Reading, Reading, RG6 6AX, UK.
| | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
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30
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Khanh TD, Xuan TD. Association and Expression of Virulence from Plasmids of the Group B Strain in Pseudomonas syringae pv. eriobotryae. Pathogens 2018; 7:pathogens7020041. [PMID: 29661998 PMCID: PMC6027306 DOI: 10.3390/pathogens7020041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/10/2018] [Accepted: 04/12/2018] [Indexed: 11/16/2022] Open
Abstract
Pseudomonas syringae pv. eriobotryae causes serious stem canker in loquat (Eriobotrya japonica) trees. This study was conducted to determine whether plasmids are involved with its virulence. The strain NAE89, which belonged to the B group, harbored two plasmids at approximately 6.2 and 50 Mdal that caused stem canker and halo leaf spots on loquat plants. Following digestion with BamHI and ligation into the BamHI cloning site of the broad range host cosmid pLAFR3, four DNA fragments at 3.8, 6.6, 12.3, and 22.8 kb were generated. Although the plasmid-encoded virulence gene psvA was undigested with the BamHI, the halo leaf spot gene may be adjacent to the psvA gene was digested. A pLAFR3 cosmid clone was introduced into the non-pathogenic PE0 and NAE89-1 strains by triparental matings and the pathogenicity was recovered. As a result, the pLAFR3 cosmid clone was introduced into the largest size DNA fragment of 22.8 kb and determined to be the causal agent of canker on the stem of the loquat. This study revealed that the psvA gene, previously found in the 50 Mdal plasmid, was also observed in the 22.8 kb DNA fragment.
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Affiliation(s)
- Tran Dang Khanh
- Agricultural Genetics Institute, Pham Van Dong Street, Hanoi 122300, Vietnam.
| | - Tran Dang Xuan
- Division of Development Technology, Graduate School for International Development and Cooperation (IDEC), Hiroshima University, Higashi Hiroshima 739-8529, Japan.
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31
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Tchagang CF, Xu R, Doumbou CL, Tambong JT. Genome analysis of two novel Pseudomonas strains exhibiting differential hypersensitivity reactions on tobacco seedlings reveals differences in nonflagellar T3SS organization and predicted effector proteins. Microbiologyopen 2018; 7:e00553. [PMID: 29464939 PMCID: PMC5911992 DOI: 10.1002/mbo3.553] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 11/06/2022] Open
Abstract
Multilocus sequence analysis (MLSA) of two new biological control strains (S1E40 and S3E12) of Pseudomonas was performed to assess their taxonomic position relative to close lineages, and comparative genomics employed to investigate whether these strains differ in key genetic features involved in hypersensitivity responses (HRs). Strain S3E12, at high concentration, incites HRs on tobacco and corn plantlets while S1E40 does not. Phylogenies based on individual genes and 16S rRNA-gyrB-rpoB-rpoD concatenated sequence data show strains S1E40 and S3E12 clustering in distinct groups. Strain S3E12 consistently clustered with Pseudomonas marginalis, a bacterium causing soft rots on plant tissues. MLSA data suggest that strains S1E40 and S3E12 are novel genotypes. This is consistent with the data of genome-based DNA-DNA homology values that are below the proposed cutoff species boundary. Comparative genomics analysis of the two strains revealed major differences in the type III secretion systems (T3SS) as well as the predicted T3SS secreted effector proteins (T3Es). One nonflagellar (NF-T3SS) and two flagellar T3SSs (F-T3SS) clusters were identified in both strains. While F-T3SS clusters in both strains were relatively conserved, the NF-T3SS clusters differed in the number of core components present. The predicted T3Es also differed in the type and number of CDSs with both strains having unique predicted protease-related effectors. In addition, the T1SS organization of the S3E12 genome has protein-coding sequences (CDSs) encoding for key factors such as T1SS secreted agglutinin repeats-toxins (a group of cytolysins and cytotoxins), a membrane fusion protein (LapC), a T1SS ATPase of LssB family (LapB), and T1SS-associated transglutaminase-like cysteine proteinase (LapP). In contrast, strain S1E40 has all CDSs for the seven-gene operon (pelA-pelG) required for Pel biosynthesis but not S3E12, suggesting that biofilm formation in these strains is modulated differently. The data presented here provide an insight of the genome organization of these two phytobacterial strains.
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Affiliation(s)
- Caetanie F. Tchagang
- Ottawa Research and Development CentreOttawaONCanada
- Institut des sciences de santé et de la vie Collège La CitéOttawaONCanada
| | - Renlin Xu
- Ottawa Research and Development CentreOttawaONCanada
| | - Cyr Lézin Doumbou
- Institut des sciences de santé et de la vie Collège La CitéOttawaONCanada
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32
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Rufián JS, Macho AP, Corry DS, Mansfield JW, Ruiz‐Albert J, Arnold DL, Beuzón CR. Confocal microscopy reveals in planta dynamic interactions between pathogenic, avirulent and non-pathogenic Pseudomonas syringae strains. MOLECULAR PLANT PATHOLOGY 2018; 19:537-551. [PMID: 28120374 PMCID: PMC6638015 DOI: 10.1111/mpp.12539] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/12/2017] [Accepted: 01/17/2017] [Indexed: 05/04/2023]
Abstract
Recent advances in genomics and single-cell analysis have demonstrated the extraordinary complexity reached by microbial populations within their hosts. Communities range from complex multispecies groups to homogeneous populations differentiating into lineages through genetic or non-genetic mechanisms. Diversity within bacterial populations is recognized as a key driver of the evolution of animal pathogens. In plants, however, little is known about how interactions between different pathogenic and non-pathogenic variants within the host impact on defence responses, or how the presence within a mixture may affect the development or the fate of each variant. Using confocal fluorescence microscopy, we analysed the colonization of the plant apoplast by individual virulence variants of Pseudomonas syringae within mixed populations. We found that non-pathogenic variants can proliferate and even spread beyond the inoculated area to neighbouring tissues when in close proximity to pathogenic bacteria. The high bacterial concentrations reached at natural entry points promote such interactions during the infection process. We also found that a diversity of interactions take place at a cellular level between virulent and avirulent variants, ranging from dominant negative effects on proliferation of virulent bacteria to in trans suppression of defences triggered by avirulent bacteria. Our results illustrate the spatial dynamics and complexity of the interactions found within mixed infections, and their potential impact on pathogen evolution.
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Affiliation(s)
- José S. Rufián
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
| | - Alberto P. Macho
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
- Present address:
Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological SciencesChinese Academy of SciencesShanghai201602China
| | - David S. Corry
- Centre for Research in Bioscience, Faculty of Health and Applied SciencesUniversity of the West of England, Frenchay CampusBristolBS16 1QYUK
| | | | - Javier Ruiz‐Albert
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
| | - Dawn L. Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied SciencesUniversity of the West of England, Frenchay CampusBristolBS16 1QYUK
| | - Carmen R. Beuzón
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
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Stice SP, Stumpf SD, Gitaitis RD, Kvitko BH, Dutta B. Pantoea ananatis Genetic Diversity Analysis Reveals Limited Genomic Diversity as Well as Accessory Genes Correlated with Onion Pathogenicity. Front Microbiol 2018; 9:184. [PMID: 29491851 PMCID: PMC5817063 DOI: 10.3389/fmicb.2018.00184] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/26/2018] [Indexed: 12/21/2022] Open
Abstract
Pantoea ananatis is a member of the family Enterobacteriaceae and an enigmatic plant pathogen with a broad host range. Although P. ananatis strains can be aggressive on onion causing foliar necrosis and onion center rot, previous genomic analysis has shown that P. ananatis lacks the primary virulence secretion systems associated with other plant pathogens. We assessed a collection of fifty P. ananatis strains collected from Georgia over three decades to determine genetic factors that correlated with onion pathogenic potential. Previous genetic analysis studies have compared strains isolated from different hosts with varying diseases potential and isolation sources. Strains varied greatly in their pathogenic potential and aggressiveness on different cultivated Allium species like onion, leek, shallot, and chive. Using multi-locus sequence analysis (MLSA) and repetitive extragenic palindrome repeat (rep)-PCR techniques, we did not observe any correlation between onion pathogenic potential and genetic diversity among strains. Whole genome sequencing and pan-genomic analysis of a sub-set of 10 strains aided in the identification of a novel series of genetic regions, likely plasmid borne, and correlating with onion pathogenicity observed on single contigs of the genetic assemblies. We named these loci Onion Virulence Regions (OVR) A-D. The OVR loci contain genes involved in redox regulation as well as pectate lyase and rhamnogalacturonase genes. Previous studies have not identified distinct genetic loci or plasmids correlating with onion foliar pathogenicity or pathogenicity on a single host pathosystem. The lack of focus on a single host system for this phytopathgenic disease necessitates the pan-genomic analysis performed in this study.
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Affiliation(s)
- Shaun P. Stice
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
| | - Spencer D. Stumpf
- Department of Plant Pathology, University of Georgia, Tifton, GA, United States
| | - Ron D. Gitaitis
- Department of Plant Pathology, University of Georgia, Tifton, GA, United States
| | - Brian H. Kvitko
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
- The Plant Center, University of Georgia, Athens, GA, United States
| | - Bhabesh Dutta
- Department of Plant Pathology, University of Georgia, Tifton, GA, United States
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Kraus CM, Mazo-Molina C, Smart CD, Martin GB. Pseudomonas syringae pv. tomato Strains from New York Exhibit Virulence Attributes Intermediate Between Typical Race 0 and Race 1 Strains. PLANT DISEASE 2017; 101:1442-1448. [PMID: 30678591 DOI: 10.1094/pdis-03-17-0330-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bacterial speck disease, caused by Pseudomonas syringae pv. tomato, is a persistent problem for fresh-market tomato growers in New York. Race 0 strains of this pathogen express either or both of the type III effectors AvrPto or AvrPtoB, which are recognized by tomato varieties expressing the Pto resistance gene. Pto encodes a protein kinase that activates the host immune system, thereby inhibiting bacterial multiplication and preventing disease development. Race 1 P. syringae pv. tomato strains do not express these effectors and are virulent on tomato whether or not the variety expresses Pto. Very few fresh-market tomato varieties have the Pto gene. We collected six P. syringae pv. tomato strains from naturally infected tomato plants across New York in 2015 and characterized them for their virulence and for the presence of specific effectors. In experiments conducted in the greenhouse, all strains reached population sizes in Pto-expressing tomato leaves that were intermediate between typical race 0 and race 1 strains. This phenotype has not been observed previously and suggests that the strains are recognized by Pto but such recognition is compromised by another P. syringae pv. tomato factor. The strains were found to encode avrPto, which is transcribed and translated. They also express avrPtoB although, as reported for other P. syringae pv. tomato strains, protein expression for this effector was not detectable. Deletion of avrPto from a representative New York strain allowed it to reach high populations in Pto-expressing tomato varieties, without compromising its virulence on susceptible tomato plants. Collectively, our data suggest that introgression of the Pto gene into fresh-market tomato varieties could enhance protection against extant P. syringae pv. tomato strains.
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Affiliation(s)
- Christine M Kraus
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, and Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
| | - Carolina Mazo-Molina
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, and Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University
| | - Gregory B Martin
- Boyce Thompson Institute for Plant Research, and Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University
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Castañeda‐Ojeda MP, López‐Solanilla E, Ramos C. Differential modulation of plant immune responses by diverse members of the Pseudomonas savastanoi pv. savastanoi HopAF type III effector family. MOLECULAR PLANT PATHOLOGY 2017; 18:625-634. [PMID: 27116193 PMCID: PMC6638205 DOI: 10.1111/mpp.12420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 05/25/2023]
Abstract
The Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system (T3SS) effector repertoire includes 33 candidates, seven of which translocate into host cells and interfere with plant defences. The present study was performed to investigate the co-existence of both plasmid- and chromosomal-encoded members of the HopAF effector family, HopAF1-1 and HopAF1-2, respectively, in the genome of NCPPB 3335. Here, we show that the HopAF1 paralogues are widely distributed in the Pseudomonas syringae complex, where HopAF1-1 is most similar to the homologues encoded by other P. syringae pathovars infecting woody hosts that belong to phylogroups 1 and 3. We show that the expression of both HopAF1-1 and HopAF-2 is transcriptionally dependent on HrpL and demonstrate their delivery into Nicotiana tabacum leaves. Although the heterologous delivery of either HopAF1-1 or HopAF1-2 significantly suppressed the production of defence-associated reactive oxygen species levels, only HopAF1-2 reduced the levels of callose deposition. Moreover, the expression of HopAF1-2 by functionally effectorless P. syringae pv. tomato DC3000D28E completely inhibited the hypersensitive response in tobacco and significantly increased the competitiveness of the strain in Nicotiana benthamiana. Despite their functional differences, subcellular localization studies reveal that green fluorescent protein (GFP) fusions to either HopAF1-1 or HopAF1-2 are targeted to the plasma membrane when they are expressed in plant cells, a process that is completely dependent on the integrity of their N-myristoylation motif. Our results further support the notion that highly similar T3SS effectors might differentially interact with diverse plant targets, even when they co-localize in the same cell compartment.
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Affiliation(s)
- M. Pilar Castañeda‐Ojeda
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga‐Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC)Campus Teatinos s/nMálagaE‐29010Spain
| | - Emilia López‐Solanilla
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid‐Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Parque Científico y Tecnológico de la UPM, Campus de MontegancedoPozuelo de AlarcónMadrid28223Spain
- Departamento de BiotecnologíaEscuela Técnica Superior de Ingenieros Agrónomos, UPMAvda. Complutense S/NMadrid28040Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga‐Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC)Campus Teatinos s/nMálagaE‐29010Spain
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Lo T, Koulena N, Seto D, Guttman DS, Desveaux D. The HopF family of Pseudomonas syringae type III secreted effectors. MOLECULAR PLANT PATHOLOGY 2017; 18:457-468. [PMID: 27061875 PMCID: PMC6638241 DOI: 10.1111/mpp.12412] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Pseudomonas syringae is a bacterial phytopathogen that utilizes the type III secretion system to inject effector proteins into plant host cells. Pseudomonas syringae can infect a wide range of plant hosts, including agronomically important crops such as tomatoes and beans. The ability of P. syringae to infect such numerous hosts is caused, in part, by the diversity of effectors employed by this phytopathogen. Over 60 different effector families exist in P. syringae; one such family is HopF, which contains over 100 distinct alleles. Despite this diversity, research has focused on only two members of this family: HopF1 from P. syringae pathovar phaseolicola 1449B and HopF2 from P. syringae pathovar tomato DC3000. In this study, we review the research on HopF family members, including their host targets and molecular mechanisms of immunity suppression, and their enzymatic function. We also provide a phylogenetic analysis of this expanding effector family which provides a basis for a proposed nomenclature to guide future research. The extensive genetic diversity that exists within the HopF family presents a great opportunity to study how functional diversification on an effector family contributes to host specialization.
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Affiliation(s)
- Timothy Lo
- Department of Cell & Systems BiologyUniversity of Toronto25 Willcocks St.TorontoONCanadaM5S 3B2
| | - Noushin Koulena
- Department of Cell & Systems BiologyUniversity of Toronto25 Willcocks St.TorontoONCanadaM5S 3B2
| | - Derek Seto
- Department of Cell & Systems BiologyUniversity of Toronto25 Willcocks St.TorontoONCanadaM5S 3B2
| | - David S. Guttman
- Department of Cell & Systems BiologyUniversity of Toronto25 Willcocks St.TorontoONCanadaM5S 3B2
- Centre for the Analysis of Genome Evolution & FunctionUniversity of TorontoTorontoONCanada
| | - Darrell Desveaux
- Department of Cell & Systems BiologyUniversity of Toronto25 Willcocks St.TorontoONCanadaM5S 3B2
- Centre for the Analysis of Genome Evolution & FunctionUniversity of TorontoTorontoONCanada
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Castañeda-Ojeda MP, Moreno-Pérez A, Ramos C, López-Solanilla E. Suppression of Plant Immune Responses by the Pseudomonas savastanoi pv. savastanoi NCPPB 3335 Type III Effector Tyrosine Phosphatases HopAO1 and HopAO2. FRONTIERS IN PLANT SCIENCE 2017; 8:680. [PMID: 28529516 PMCID: PMC5418354 DOI: 10.3389/fpls.2017.00680] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/13/2017] [Indexed: 05/12/2023]
Abstract
The effector repertoire of the olive pathogen P. savastanoi pv. savastanoi NCPPB 3335 includes two members of the HopAO effector family, one of the most diverse T3E families of the P. syringae complex. The study described here explores the phylogeny of these dissimilar members, HopAO1 and HopAO2, among the complex and reveals their activities as immune defense suppressors. Although HopAO1 is predominantly encoded by phylogroup 3 strains isolated from woody organs of woody hosts, both HopAO1 and HopAO2 are phylogenetically clustered according to the woody/herbaceous nature of their host of isolation, suggesting host specialization of the HopAO family across the P. syringae complex. HopAO1 and HopAO2 translocate into plant cells and show hrpL-dependent expression, which allows their classification as actively deployed type III effectors. Our data also show that HopAO1 and HopAO2 possess phosphatase activity, a hallmark of the members of this family. Both of them exert an inhibitory effect on early plant defense responses, such as ROS production and callose deposition, and are able to suppress ETI responses induced by the effectorless polymutant of P. syringae pv. tomato DC3000 (DC3000D28E) in Nicotiana. Moreover, we demonstrate that a ΔhopAO1 mutant of P. savastanoi NCPBB 3335 exhibits a reduced fitness and virulence in olive plants, which supports the relevance of this effector during the interaction of this strain with its host plants. This work contributes to the field with the first report regarding functional analysis of HopAO homologs encoded by P. syringae or P. savastanoi strains isolated from woody hosts.
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Affiliation(s)
- María Pilar Castañeda-Ojeda
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Alba Moreno-Pérez
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Emilia López-Solanilla
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid – Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Parque Científico y Tecnológico de la UPMMadrid, Spain
- Departamento de Biotecnología y Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de MadridMadrid, Spain
- *Correspondence: Emilia López-Solanilla,
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Ji Z, Ji C, Liu B, Zou L, Chen G, Yang B. Interfering TAL effectors of Xanthomonas oryzae neutralize R-gene-mediated plant disease resistance. Nat Commun 2016; 7:13435. [PMID: 27811915 PMCID: PMC5097170 DOI: 10.1038/ncomms13435] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 10/04/2016] [Indexed: 12/21/2022] Open
Abstract
Plant pathogenic bacteria of the genus Xanthomonas possess transcription activator-like effectors (TALEs) that activate transcription of disease susceptibility genes in the host, inducing a state of disease. Here we report that some isolates of the rice pathogen Xanthomonas oryzae use truncated versions of TALEs (which we term interfering TALEs, or iTALEs) to overcome disease resistance. In comparison with typical TALEs, iTALEs lack a transcription activation domain but retain nuclear localization motifs and are expressed from genes that were previously considered pseudogenes. We show that the rice gene Xa1, encoding a nucleotide-binding leucine-rich repeat protein, confers resistance against X. oryzae isolates by recognizing multiple TALEs. However, the iTALEs present in many isolates interfere with the otherwise broad-spectrum resistance conferred by Xa1. Our findings illustrate how bacterial effectors that trigger disease resistance in the host can evolve to interfere with the resistance process and, thus, promote disease. The rice pathogen Xanthomonas oryzae produces TAL effectors (TALEs) that promote virulence. Here, the authors identify truncated TALEs that interfere with the function of a rice gene, Xa1, which confers resistance to all tested full-length TALEs.
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Affiliation(s)
- Zhiyuan Ji
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China.,Department of Genetics, Development and Cell Biology, Iowa State University, 1035C Roy J. Carver Co-Lab, Ames, Iowa 50011, USA
| | - Chonghui Ji
- Department of Genetics, Development and Cell Biology, Iowa State University, 1035C Roy J. Carver Co-Lab, Ames, Iowa 50011, USA
| | - Bo Liu
- Department of Genetics, Development and Cell Biology, Iowa State University, 1035C Roy J. Carver Co-Lab, Ames, Iowa 50011, USA
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bing Yang
- Department of Genetics, Development and Cell Biology, Iowa State University, 1035C Roy J. Carver Co-Lab, Ames, Iowa 50011, USA
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Rufián JS, Sánchez-Romero MA, López-Márquez D, Macho AP, Mansfield JW, Arnold DL, Ruiz-Albert J, Casadesús J, Beuzón CR. Pseudomonas syringae Differentiates into Phenotypically Distinct Subpopulations During Colonization of a Plant Host. Environ Microbiol 2016; 18:3593-3605. [PMID: 27516206 DOI: 10.1111/1462-2920.13497] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/09/2016] [Indexed: 11/28/2022]
Abstract
Bacterial microcolonies with heterogeneous sizes are formed during colonization of Phaseolus vulgaris by Pseudomonas syringae. Heterogeneous expression of structural and regulatory components of the P. syringae type III secretion system (T3SS), essential for colonization of the host apoplast and disease development, is likewise detected within the plant apoplast. T3SS expression is bistable in the homogeneous environment of nutrient-limited T3SS-inducing medium, suggesting that subpopulation formation is not a response to different environmental cues. T3SS bistability is reversible, indicating a non-genetic origin, and the T3SSHIGH and T3SSLOW subpopulations show differences in virulence. T3SS bistability requires the transcriptional activator HrpL, the double negative regulatory loop established by HrpV and HrpG, and may be enhanced through a positive feedback loop involving HrpA, the main component of the T3SS pilus. To our knowledge, this is the first example of phenotypic heterogeneity in the expression of virulence determinants during colonization of a non-mammalian host.
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Affiliation(s)
- José S Rufián
- Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain
| | | | - Diego López-Márquez
- Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain
| | - Alberto P Macho
- Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain
| | - John W Mansfield
- Faculty of Natural Sciences, Imperial College, London, SW7 2AZ, UK
| | - Dawn L Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK
| | - Javier Ruiz-Albert
- Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain
| | - Josep Casadesús
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, 1095, Spain
| | - Carmen R Beuzón
- Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain.
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40
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Neale HC, Laister R, Payne J, Preston G, Jackson RW, Arnold DL. A low frequency persistent reservoir of a genomic island in a pathogen population ensures island survival and improves pathogen fitness in a susceptible host. Environ Microbiol 2016; 18:4144-4152. [PMID: 27491006 PMCID: PMC5573919 DOI: 10.1111/1462-2920.13482] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/02/2016] [Indexed: 11/29/2022]
Abstract
The co-evolution of bacterial plant pathogens and their hosts is a complex and dynamic process. Host resistance imposes stress on invading pathogens that can lead to changes in the bacterial genome enabling the pathogen to escape host resistance. We have observed this phenomenon with the plant pathogen Pseudomonas syringae pv. phaseolicola where isolates that have lost the genomic island PPHGI-1 carrying the effector gene avrPphB from its chromosome are infective against previously resistant plant hosts. However, we have never observed island extinction from the pathogen population within a host suggesting the island is maintained. Here, we present a mathematical model which predicts different possible fates for the island in the population; one outcome indicated that PPHGI-1 would be maintained at low frequency in the population long term, if it confers a fitness benefit. We empirically tested this prediction and determined that PPHGI-1 frequency in the bacterial population drops to a low but consistently detectable level during host resistance. Once PPHGI-1-carrying cells encounter a susceptible host, they rapidly increase in the population in a negative frequency-dependent manner. Importantly, our data show that mobile genetic elements can persist within the bacterial population and increase in frequency under favourable conditions.
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Affiliation(s)
- Helen C Neale
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, The University of the West of England, Frenchay Campus, Bristol, BS16 1QY, UK
| | - Robert Laister
- Department of Engineering Design and Mathematics, The University of the West of England, Frenchay Campus, Bristol, BS16 1QY, UK
| | - Joseph Payne
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, The University of the West of England, Frenchay Campus, Bristol, BS16 1QY, UK
| | - Gail Preston
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK
| | - Dawn L Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, The University of the West of England, Frenchay Campus, Bristol, BS16 1QY, UK
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Sistrom M, Park D, O’Brien HE, Wang Z, Guttman DS, Townsend JP, Turner PE. Genomic and Gene-Expression Comparisons among Phage-Resistant Type-IV Pilus Mutants of Pseudomonas syringae pathovar phaseolicola. PLoS One 2015; 10:e0144514. [PMID: 26670219 PMCID: PMC4687649 DOI: 10.1371/journal.pone.0144514] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/19/2015] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas syringae pv. phaseolicola (Pph) is a significant bacterial pathogen of agricultural crops, and phage Φ6 and other members of the dsRNA virus family Cystoviridae undergo lytic (virulent) infection of Pph, using the type IV pilus as the initial site of cellular attachment. Despite the popularity of Pph/phage Φ6 as a model system in evolutionary biology, Pph resistance to phage Φ6 remains poorly characterized. To investigate differences between phage Φ6 resistant Pph strains, we examined genomic and gene expression variation among three bacterial genotypes that differ in the number of type IV pili expressed per cell: ordinary (wild-type), non-piliated, and super-piliated. Genome sequencing of non-piliated and super-piliated Pph identified few mutations that separate these genotypes from wild type Pph--and none present in genes known to be directly involved in type IV pilus expression. Expression analysis revealed that 81.1% of gene ontology (GO) terms up-regulated in the non-piliated strain were down-regulated in the super-piliated strain. This differential expression is particularly prevalent in genes associated with respiration--specifically genes in the tricarboxylic acid cycle (TCA) cycle, aerobic respiration, and acetyl-CoA metabolism. The expression patterns of the TCA pathway appear to be generally up and down-regulated, in non-piliated and super-piliated Pph respectively. As pilus retraction is mediated by an ATP motor, loss of retraction ability might lead to a lower energy draw on the bacterial cell, leading to a different energy balance than wild type. The lower metabolic rate of the super-piliated strain is potentially a result of its loss of ability to retract.
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Affiliation(s)
- Mark Sistrom
- School of Natural Sciences, University of California Merced, Merced, 95343, CA, United States of America
- * E-mail:
| | - Derek Park
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, United States of America
| | - Heath E. O’Brien
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
| | - Zheng Wang
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, United States of America
| | - David S. Guttman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Ontario, M5S 3B2, Canada
| | - Jeffrey P. Townsend
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, United States of America
- Department of Biostatistics, Yale School of Public Health, New Haven, CT 06520, United States of America
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, United States of America
- Program in Microbiology, Yale University, New Haven, CT 06520, United States of America
| | - Paul E. Turner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, United States of America
- Program in Microbiology, Yale University, New Haven, CT 06520, United States of America
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Wei HL, Chakravarthy S, Mathieu J, Helmann TC, Stodghill P, Swingle B, Martin GB, Collmer A. Pseudomonas syringae pv. tomato DC3000 Type III Secretion Effector Polymutants Reveal an Interplay between HopAD1 and AvrPtoB. Cell Host Microbe 2015; 17:752-62. [PMID: 26067603 PMCID: PMC4471848 DOI: 10.1016/j.chom.2015.05.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 03/05/2015] [Accepted: 04/17/2015] [Indexed: 11/20/2022]
Abstract
The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 suppresses the two-tiered plant innate immune system by injecting a complex repertoire of type III secretion effector (T3E) proteins. Beyond redundancy and interplay, individual T3Es may interact with multiple immunity-associated proteins, rendering their analysis challenging. We constructed a Pst DC3000 polymutant lacking all 36 T3Es and restored individual T3Es or their mutants to explore the interplay among T3Es. The weakly expressed T3E HopAD1 was sufficient to elicit immunity-associated cell death in Nicotiana benthamiana. HopAD1-induced cell death was suppressed partially by native AvrPtoB and completely by AvrPtoBM3, which has mutations disrupting its E3 ubiquitin ligase domain and two known domains for interacting with immunity-associated kinases. AvrPtoBM3 also gained the ability to interact with the immunity-kinase MKK2, which is required for HopAD1-dependent cell death. Thus, AvrPtoB has alternative, competing mechanisms for suppressing effector-triggered plant immunity. This approach allows the deconvolution of individual T3E activities.
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Affiliation(s)
- Hai-Lei Wei
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Suma Chakravarthy
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Johannes Mathieu
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
| | - Tyler C Helmann
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Paul Stodghill
- United States Department of Agriculture-Agricultural Research Service, Ithaca, NY 14853, USA
| | - Bryan Swingle
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; United States Department of Agriculture-Agricultural Research Service, Ithaca, NY 14853, USA
| | - Gregory B Martin
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
| | - Alan Collmer
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
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Mendes-Soares H, Krishnan V, Settles ML, Ravel J, Brown CJ, Forney LJ. Fine-scale analysis of 16S rRNA sequences reveals a high level of taxonomic diversity among vaginal Atopobium spp. Pathog Dis 2015; 73:ftv020. [PMID: 25778779 DOI: 10.1093/femspd/ftv020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2015] [Indexed: 01/29/2023] Open
Abstract
Although vaginal microbial communities of some healthy women have high proportions of Atopobium vaginae, the genus Atopobium is more commonly associated with bacterial vaginosis, a syndrome associated with an increased risk of adverse pregnancy outcomes and the transmission of sexually transmitted diseases. Genetic differences within Atopobium species may explain why single species can be associated with both health and disease. We used 16S rRNA gene sequences from previously published studies to explore the taxonomic diversity of the genus Atopobium in vaginal microbial communities of healthy women. Although A. vaginae was the species most commonly found, we also observed three other Atopobium species in the vaginal microbiota, one of which, A. parvulum, was not previously known to reside in the human vagina. Furthermore, we found several potential novel species of the genus Atopobium and multiple phylogenetic clades of A. vaginae. The diversity of Atopobium found in our study, which focused only on samples from healthy women, is greater than previously recognized, suggesting that analysis of samples from women with BV would yield even more diversity. Classification of microbes only to the genus level may thus obfuscate differences that might be important to better understand health or disease.
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Affiliation(s)
- Helena Mendes-Soares
- Department of Biological Sciences and Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow ID 83844, USA
| | - Vandhana Krishnan
- Department of Biological Sciences and Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow ID 83844, USA
| | - Matthew L Settles
- Department of Biological Sciences and Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow ID 83844, USA
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore MD 21201, USA
| | - Celeste J Brown
- Department of Biological Sciences and Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow ID 83844, USA
| | - Larry J Forney
- Department of Biological Sciences and Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow ID 83844, USA
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44
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Matas IM, Castañeda-Ojeda MP, Aragón IM, Antúnez-Lamas M, Murillo J, Rodríguez-Palenzuela P, López-Solanilla E, Ramos C. Translocation and functional analysis of Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system effectors reveals two novel effector families of the Pseudomonas syringae complex. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:424-36. [PMID: 24329173 DOI: 10.1094/mpmi-07-13-0206-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pseudomonas savastanoi pv. savastanoi NCPPB 3335 causes olive knot disease and is a model pathogen for exploring bacterial infection of woody hosts. The type III secretion system (T3SS) effector repertoire of this strain includes 31 effector candidates plus two novel candidates identified in this study which have not been reported to translocate into plant cells. In this work, we demonstrate the delivery of seven NCPPB 3335 effectors into Nicotiana tabacum leaves, including three proteins from two novel families of the P. syringae complex effector super-repertoire (HopBK and HopBL), one of which comprises two proteins (HopBL1 and HopBL2) that harbor a SUMO protease domain. When delivered by P. fluorescens heterologously expressing a P. syringae T3SS, all seven effectors were found to suppress the production of defense-associated reactive oxygen species. Moreover, six of these effectors, including the truncated versions of HopAA1 and HopAZ1 encoded by NCPPB 3335, suppressed callose deposition. The expression of HopAZ1 and HopBL1 by functionally effectorless P. syringae pv. tomato DC3000D28E inhibited the hypersensitive response in tobacco and, additionally, expression of HopBL2 by this strain significantly increased its competitiveness in N. benthamiana. DNA sequences encoding HopBL1 and HopBL2 were uniquely detected in a collection of 31 P. savastanoi pv. savastanoi strains and other P. syringae strains isolated from woody hosts, suggesting a relevant role of these two effectors in bacterial interactions with olive and other woody plants.
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Bartoli C, Berge O, Monteil CL, Guilbaud C, Balestra GM, Varvaro L, Jones C, Dangl JL, Baltrus DA, Sands DC, Morris CE. ThePseudomonas viridiflavaphylogroups in theP. syringaespecies complex are characterized by genetic variability and phenotypic plasticity of pathogenicity-related traits. Environ Microbiol 2014; 16:2301-15. [DOI: 10.1111/1462-2920.12433] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/13/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Claudia Bartoli
- Department of Science and Technology for Agriculture, Forestry, Nature and Energy (DAFNE); Tuscia University; Viterbo Italy
- UR0407 Pathologie Végétale; INRA; Montfavet France
| | - Odile Berge
- UR0407 Pathologie Végétale; INRA; Montfavet France
| | | | | | - Giorgio M. Balestra
- Department of Science and Technology for Agriculture, Forestry, Nature and Energy (DAFNE); Tuscia University; Viterbo Italy
| | - Leonardo Varvaro
- Department of Science and Technology for Agriculture, Forestry, Nature and Energy (DAFNE); Tuscia University; Viterbo Italy
| | - Corbin Jones
- Department of Biology; Carolina Center for Genome Sciences; Chapel Hill NC 29599 USA
| | - Jeffery L. Dangl
- Department of Biology; Howard Hughes Medical Institute; University of North Carolina; Chapel Hill NC 29599 USA
| | - David A. Baltrus
- School of Plant Sciences; University of Arizona; Tucson AZ 85721 USA
| | - David C. Sands
- Department Plant Sciences and Plant Pathology; Montana State University; Bozeman MT 59717-3150 USA
| | - Cindy E. Morris
- UR0407 Pathologie Végétale; INRA; Montfavet France
- Department Plant Sciences and Plant Pathology; Montana State University; Bozeman MT 59717-3150 USA
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Block A, Toruño TY, Elowsky CG, Zhang C, Steinbrenner J, Beynon J, Alfano JR. The Pseudomonas syringae type III effector HopD1 suppresses effector-triggered immunity, localizes to the endoplasmic reticulum, and targets the Arabidopsis transcription factor NTL9. THE NEW PHYTOLOGIST 2014; 201:1358-1370. [PMID: 24329768 DOI: 10.1111/nph.12626] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 10/30/2013] [Indexed: 05/23/2023]
Abstract
• Pseudomonas syringae type III effectors are known to suppress plant immunity to promote bacterial virulence. However, the activities and targets of these effectors are not well understood. • We used genetic, molecular, and cell biology methods to characterize the activities, localization, and target of the HopD1 type III effector in Arabidopsis. • HopD1 contributes to P. syringae virulence in Arabidopsis and reduces effector-triggered immunity (ETI) responses but not pathogen-associated molecular pattern-triggered immunity (PTI) responses. Plants expressing HopD1 supported increased growth of ETI-inducing P. syringae strains compared with wild-type Arabidopsis. We show that HopD1 interacts with the membrane-tethered Arabidopsis transcription factor NTL9 and demonstrate that this interaction occurs at the endoplasmic reticulum (ER). A P. syringae hopD1 mutant and ETI-inducing P. syringae strains exhibited enhanced growth on Arabidopsis ntl9 mutant plants. Conversely, growth of P. syringae strains was reduced in plants expressing a constitutively active NTL9 derivative, indicating that NTL9 is a positive regulator of plant immunity. Furthermore, HopD1 inhibited the induction of NTL9-regulated genes during ETI but not PTI. • HopD1 contributes to P. syringae virulence in part by targeting NTL9, resulting in the suppression of ETI responses but not PTI responses and the promotion of plant pathogenicity.
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Affiliation(s)
- Anna Block
- Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, 68588-0722, USA
| | - Tania Y Toruño
- Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, 68588-0722, USA
| | - Christian G Elowsky
- Center for Biotechnology, University of Nebraska, Lincoln, NE, 68588-0665, USA
| | - Chi Zhang
- Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA
- School of Biological Sciences, University of Nebraska, Lincoln, NE, 68588-0118, USA
| | - Jens Steinbrenner
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Jim Beynon
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - James R Alfano
- Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA
- Department of Plant Pathology, University of Nebraska, Lincoln, NE, 68588-0722, USA
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Bao Z, Stodghill PV, Myers CR, Lam H, Wei HL, Chakravarthy S, Kvitko BH, Collmer A, Cartinhour SW, Schweitzer P, Swingle B. Genomic plasticity enables phenotypic variation of Pseudomonas syringae pv. tomato DC3000. PLoS One 2014; 9:e86628. [PMID: 24516535 PMCID: PMC3916326 DOI: 10.1371/journal.pone.0086628] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/16/2013] [Indexed: 11/18/2022] Open
Abstract
Whole genome sequencing revealed the presence of a genomic anomaly in the region of 4.7 to 4.9 Mb of the Pseudomonas syringae pv. tomato (Pst) DC3000 genome. The average read depth coverage of Pst DC3000 whole genome sequencing results suggested that a 165 kb segment of the chromosome had doubled in copy number. Further analysis confirmed the 165 kb duplication and that the two copies were arranged as a direct tandem repeat. Examination of the corresponding locus in Pst NCPPB1106, the parent strain of Pst DC3000, suggested that the 165 kb duplication most likely formed after the two strains diverged via transposition of an ISPsy5 insertion sequence (IS) followed by unequal crossing over between ISPsy5 elements at each end of the duplicated region. Deletion of one copy of the 165 kb region demonstrated that the duplication facilitated enhanced growth in some culture conditions, but did not affect pathogenic growth in host tomato plants. These types of chromosomal structures are predicted to be unstable and we have observed resolution of the 165 kb duplication to single copy and its subsequent re-duplication. These data demonstrate the role of IS elements in recombination events that facilitate genomic reorganization in P. syringae.
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Affiliation(s)
- Zhongmeng Bao
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Paul V. Stodghill
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Christopher R. Myers
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York, United States of America
| | - Hanh Lam
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Suma Chakravarthy
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Brian H. Kvitko
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Samuel W. Cartinhour
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Peter Schweitzer
- Biotechnology Resource Center, Cornell University, Ithaca, New York, United States of America
| | - Bryan Swingle
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
- * E-mail:
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Teper D, Salomon D, Sunitha S, Kim JG, Mudgett MB, Sessa G. Xanthomonas euvesicatoria type III effector XopQ interacts with tomato and pepper 14-3-3 isoforms to suppress effector-triggered immunity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:297-309. [PMID: 24279912 DOI: 10.1111/tpj.12391] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 05/09/2023]
Abstract
Effector-triggered immunity (ETI) to host-adapted pathogens is associated with rapid cell death at the infection site. The plant-pathogenic bacterium Xanthomonas euvesicatoria (Xcv) interferes with plant cellular processes by injecting effector proteins into host cells through the type III secretion system. Here, we show that the Xcv effector XopQ suppresses cell death induced by components of the ETI-associated MAP kinase cascade MAPKKKα MEK2/SIPK and by several R/avr gene pairs. Inactivation of xopQ by insertional mutagenesis revealed that this effector inhibits ETI-associated cell death induced by avirulent Xcv in resistant pepper (Capsicum annuum), and enhances bacterial growth in resistant pepper and tomato (Solanum lycopersicum). Using protein-protein interaction studies in yeast (Saccharomyces cerevisiae) and in planta, we identified the tomato 14-3-3 isoform SlTFT4 and homologs from other plant species as XopQ interactors. A mutation in the putative 14-3-3 binding site of XopQ impaired interaction of the effector with CaTFT4 in yeast and its virulence function in planta. Consistent with a role in ETI, TFT4 mRNA abundance increased during the incompatible interaction of tomato and pepper with Xcv. Silencing of NbTFT4 in Nicotiana benthamiana significantly reduced cell death induced by MAPKKKα. In addition, silencing of CaTFT4 in pepper delayed the appearance of ETI-associated cell death and enhanced growth of virulent and avirulent Xcv, demonstrating the requirement of TFT4 for plant immunity to Xcv. Our results suggest that the XopQ virulence function is to suppress ETI and immunity-associated cell death by interacting with TFT4, which is an important component of ETI and a bona fide target of XopQ.
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Affiliation(s)
- Doron Teper
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, 69978, Tel Aviv, Israel
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Khatabi B, Wen RH, Hajimorad MR. Fitness penalty in susceptible host is associated with virulence of Soybean mosaic virus on Rsv1-genotype soybean: a consequence of perturbation of HC-Pro and not P3. MOLECULAR PLANT PATHOLOGY 2013; 14:885-97. [PMID: 23782556 PMCID: PMC6638797 DOI: 10.1111/mpp.12054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The multigenic Rsv1 locus in the soybean plant introduction (PI) 'PI96983' confers extreme resistance against the majority of Soybean mosaic virus (SMV) strains, including SMV-N, but not SMV-G7 and SMV-G7d. In contrast, in susceptible soybean cultivars lacking a functional Rsv1 locus, such as 'Williams82' (rsv1), SMV-N induces severe disease symptoms and accumulates to a high level, whereas both SMV-G7 and SMV-G7d induce mild symptoms and accumulate to a significantly lower level. Gain of virulence by SMV-N on Rsv1-genotype soybean requires concurrent mutations in both the helper-component proteinase (HC-Pro) and P3 cistrons. This is because of the presence of at least two resistance (R) genes, probably belonging to the nucleotide-binding leucine-rich repeat (NB-LRR) class, within the Rsv1 locus, independently mediating the recognition of HC-Pro or P3. In this study, we show that the majority of experimentally evolved mutational pathways that disrupt the avirulence functions of SMV-N on Rsv1-genotype soybean also result in mild symptoms and reduced accumulation, relative to parental SMV-N, in Williams82 (rsv1). Furthermore, the evaluation of SMV-N-derived HC-Pro and P3 chimeras, containing homologous sequences from virulent SMV-G7 or SMV-G7d strains, as well as SMV-N-derived variants containing HC-Pro or P3 point mutation(s) associated with gain of virulence, reveals a direct correlation between the perturbation of HC-Pro and a fitness penalty in Williams82 (rsv1). Collectively, these data demonstrate that gain of virulence by SMV on Rsv1-genotype soybean results in fitness loss in a previously susceptible soybean genotype, this being a consequence of mutations in HC-Pro, but not in P3.
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Affiliation(s)
- B Khatabi
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN, 37996, USA
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Neale HC, Slater RT, Mayne LM, Manoharan B, Arnold DL. In planta induced changes in the native plasmid profile of Pseudomonas syringae pathover phaseolicola strain 1302A. Plasmid 2013; 70:420-4. [DOI: 10.1016/j.plasmid.2013.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/05/2013] [Accepted: 07/11/2013] [Indexed: 10/26/2022]
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