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Cruz AAD, Cabeo M, Durán-Viseras A, Sampedro I, Llamas I. Interference of AHL signal production in the phytophatogen Pantoea agglomerans as a sustainable biological strategy to reduce its virulence. Microbiol Res 2024; 285:127781. [PMID: 38795406 DOI: 10.1016/j.micres.2024.127781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 04/23/2024] [Accepted: 05/21/2024] [Indexed: 05/28/2024]
Abstract
Pantoea agglomerans is considered one of the most ubiquitous and versatile organisms that include strains that induce diseases in various crops and occasionally cause opportunistic infections in humans. To develop effective strategies to mitigate its impact on plant health and agricultural productivity, a comprehensive investigation is crucial for better understanding its pathogenicity. One proposed eco-friendly approach involves the enzymatic degradation of quorum sensing (QS) signal molecules like N-acylhomoserine lactones (AHLs), known as quorum quenching (QQ), offering potential treatment for such bacterial diseases. In this study the production of C4 and 3-oxo-C6HSL was identified in the plant pathogenic P. agglomerans CFBP 11141 and correlated to enzymatic activities such as amylase and acid phosphatase. Moreover, the heterologous expression of a QQ enzyme in the pathogen resulted in lack of AHLs production and the attenuation of the virulence by mean of drastically reduction of soft rot disease in carrots and cherry tomatoes. Additionally, the interference with the QS systems of P. agglomerans CFBP 11141 by two the plant growth-promoting and AHL-degrading bacteria (PGP-QQ) Pseudomonas segetis P6 and Bacillus toyonensis AA1EC1 was evaluated as a potential biocontrol approach for the first time. P. segetis P6 and B. toyonensis AA1EC1 demonstrated effectiveness in diminishing soft rot symptoms induced by P. agglomerans CFBP 11141 in both carrots and cherry tomatoes. Furthermore, the virulence of pathogen notably decreased when co-cultured with strain AA1EC1 on tomato plants.
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Affiliation(s)
- Alba Amaro-da Cruz
- Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, Granada 18071, Spain
| | - Mónica Cabeo
- Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, Granada 18071, Spain
| | - Ana Durán-Viseras
- Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, Granada 18071, Spain
| | - Inmaculada Sampedro
- Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, Granada 18071, Spain; Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada 18106, Spain.
| | - Inmaculada Llamas
- Department of Microbiology, Faculty of Pharmacy, Cartuja Campus, University of Granada, Granada 18071, Spain; Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada 18106, Spain.
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2
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Roca A, Cabeo M, Enguidanos C, Martínez-Checa F, Sampedro I, Llamas I. Potential of the quorum-quenching and plant-growth promoting halotolerant Bacillus toyonensis AA1EC1 as biocontrol agent. Microb Biotechnol 2024; 17:e14420. [PMID: 38532596 DOI: 10.1111/1751-7915.14420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 03/28/2024] Open
Abstract
The use of fertilizers and pesticides to control plant diseases is widespread in intensive farming causing adverse effects together with the development of antimicrobial resistance pathogens. As the virulence of many Gram-negative phytopathogens is controlled by N-acyl-homoserine lactones (AHLs), the enzymatic disruption of this type of quorum-sensing (QS) signal molecules, mechanism known as quorum quenching (QQ), has been proposed as a promising alternative antivirulence therapy. In this study, a novel strain of Bacillus toyonensis isolated from the halophyte plant Arthrocaulon sp. exhibited numerous traits associated with plant growth promotion (PGP) and degraded a broad range of AHLs. Three lactonases and an acylase enzymes were identified in the bacterial genome and verified in vitro. The AHL-degrading activity of strain AA1EC1 significantly attenuated the virulence of relevant phytopathogens causing reduction of soft rot symptoms on potato and carrots. In vivo assays showed that strain AA1EC1 significantly increased plant length, stem width, root and aerial dry weights and total weight of tomato and protected plants against Pseudomonas syringae pv. tomato. To our knowledge, this is the first report to demonstrate PGP and QQ activities in the species B. toyonensis that make this strain as a promising phytostimulant and biocontrol agent.
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Affiliation(s)
- Amalia Roca
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
| | - Mónica Cabeo
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Carlos Enguidanos
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Fernando Martínez-Checa
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
| | - Inmaculada Sampedro
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
| | - Inmaculada Llamas
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
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3
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Fautt C, Couradeau E, Hockett KL. Naïve Bayes Classifiers and accompanying dataset for Pseudomonas syringae isolate characterization. Sci Data 2024; 11:178. [PMID: 38326362 PMCID: PMC10850129 DOI: 10.1038/s41597-024-03003-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 01/26/2024] [Indexed: 02/09/2024] Open
Abstract
The Pseudomonas syringae species complex (PSSC) is a diverse group of plant pathogens with a collective host range encompassing almost every food crop grown today. As a threat to global food security, rapid detection and characterization of epidemic and emerging pathogenic lineages is essential. However, phylogenetic identification is often complicated by an unclarified and ever-changing taxonomy, making practical use of available databases and the proper training of classifiers difficult. As such, while amplicon sequencing is a common method for routine identification of PSSC isolates, there is no efficient method for accurate classification based on this data. Here we present a suite of five Naïve bayes classifiers for PCR primer sets widely used for PSSC identification, trained on in-silico amplicon data from 2,161 published PSSC genomes using the life identification number (LIN) hierarchical clustering algorithm in place of traditional Linnaean taxonomy. Additionally, we include a dataset for translating classification results back into traditional taxonomic nomenclature (i.e. species, phylogroup, pathovar), and for predicting virulence factor repertoires.
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Affiliation(s)
- Chad Fautt
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania, USA.
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, Pennsylvania, USA.
- Intercollege Graduate Degree Program in Ecology, Pennsylvania State University, University Park, Pennsylvania, USA.
| | - Estelle Couradeau
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, Pennsylvania, USA.
- Intercollege Graduate Degree Program in Ecology, Pennsylvania State University, University Park, Pennsylvania, USA.
| | - Kevin L Hockett
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania, USA.
- Intercollege Graduate Degree Program in Ecology, Pennsylvania State University, University Park, Pennsylvania, USA.
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Fautt C, Hockett KL, Couradeau E. Evaluation of the taxonomic accuracy and pathogenicity prediction power of 16 primer sets amplifying single copy marker genes in the Pseudomonas syringae species complex. MOLECULAR PLANT PATHOLOGY 2023; 24:989-998. [PMID: 37132320 PMCID: PMC10346468 DOI: 10.1111/mpp.13337] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 02/24/2023] [Accepted: 03/23/2023] [Indexed: 05/04/2023]
Abstract
The Pseudomonas syringae species complex is composed of several closely related species of bacterial plant pathogens. Here, we used in silico methods to assess 16 PCR primer sets designed for broad identification of isolates throughout the species complex. We evaluated their in silico amplification rate in 2161 publicly available genomes, the correlation between pairwise amplicon sequence distance and whole genome average nucleotide identity, and trained naive Bayes classification models to quantify classification resolution. Furthermore, we show the potential for using single amplicon sequence data to predict type III effector protein repertoires, which are important determinants of host specificity and range.
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Affiliation(s)
- Chad Fautt
- Department of Plant Pathology and Environmental MicrobiologyPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
- Department of Ecosystem Science and ManagementPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
- Intercollege Graduate Degree Program in EcologyPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Kevin L. Hockett
- Department of Plant Pathology and Environmental MicrobiologyPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
- Intercollege Graduate Degree Program in EcologyPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Estelle Couradeau
- Department of Ecosystem Science and ManagementPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
- Intercollege Graduate Degree Program in EcologyPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
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5
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New Insights into the Taxonomy of Bacteria in the Genomic Era and a Case Study with Rhizobia. Int J Microbiol 2022; 2022:4623713. [PMID: 35637770 PMCID: PMC9148247 DOI: 10.1155/2022/4623713] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 05/09/2022] [Indexed: 12/15/2022] Open
Abstract
Since early studies, the history of prokaryotes taxonomy has dealt with many changes driven by the development of new and more robust technologies. As a result, the number of new taxa descriptions is exponentially increasing, while an increasing number of others has been subject of reclassification, demanding from the taxonomists more effort to maintain an organized hierarchical system. However, expectations are that the taxonomy of prokaryotes will acquire a more stable status with the genomic era. Other analyses may continue to be necessary to determine microbial features, but the use of genomic data might be sufficient to provide reliable taxa delineation, helping taxonomy to reach the goal of correct classification and identification. Here we describe the evolution of prokaryotes' taxonomy until the genomic era, emphasizing bacteria and taking as an example the history of rhizobia taxonomy. This example was chosen because of the importance of the symbiotic nitrogen fixation of legumes with rhizobia to the nitrogen input to both natural ecosystems and agricultural crops. This case study reports the technological advances and the methodologies used to classify and identify bacterial species and indicates the actual rules required for an accurate description of new taxa.
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Iquebal MA, Jagannadham J, Jaiswal S, Prabha R, Rai A, Kumar D. Potential Use of Microbial Community Genomes in Various Dimensions of Agriculture Productivity and Its Management: A Review. Front Microbiol 2022; 13:708335. [PMID: 35655999 PMCID: PMC9152772 DOI: 10.3389/fmicb.2022.708335] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 03/17/2022] [Indexed: 12/12/2022] Open
Abstract
Agricultural productivity is highly influenced by its associated microbial community. With advancements in omics technology, metagenomics is known to play a vital role in microbial world studies by unlocking the uncultured microbial populations present in the environment. Metagenomics is a diagnostic tool to target unique signature loci of plant and animal pathogens as well as beneficial microorganisms from samples. Here, we reviewed various aspects of metagenomics from experimental methods to techniques used for sequencing, as well as diversified computational resources, including databases and software tools. Exhaustive focus and study are conducted on the application of metagenomics in agriculture, deciphering various areas, including pathogen and plant disease identification, disease resistance breeding, plant pest control, weed management, abiotic stress management, post-harvest management, discoveries in agriculture, source of novel molecules/compounds, biosurfactants and natural product, identification of biosynthetic molecules, use in genetically modified crops, and antibiotic-resistant genes. Metagenomics-wide association studies study in agriculture on crop productivity rates, intercropping analysis, and agronomic field is analyzed. This article is the first of its comprehensive study and prospects from an agriculture perspective, focusing on a wider range of applications of metagenomics and its association studies.
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Affiliation(s)
- Mir Asif Iquebal
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, India
| | - Jaisri Jagannadham
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, India
| | - Sarika Jaiswal
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, India
| | - Ratna Prabha
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, India
| | - Anil Rai
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, India
| | - Dinesh Kumar
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, India
- School of Interdisciplinary and Applied Sciences, Central University of Haryana, Mahendergarh, Haryana, India
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Li Y, Jiao C, Wei Z, Chai S, Jia H, Gao M, Allison J, Li Z, Song CB, Wang X. Analysis of Grapevine's Somatic Embryogenesis Receptor Kinase (SERK) Gene Family: VqSERK3/BAK1 Overexpression Enhances Disease Resistance. PHYTOPATHOLOGY 2022; 112:1081-1092. [PMID: 34698542 DOI: 10.1094/phyto-04-21-0136-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The somatic embryogenesis receptor kinase (SERK) gene family has been intensively studied in several plant species. Here we confirmed the existence of five SERK genes in grapevine (Chinese wild grapevine Vitis quinquangularis) and named them VqSERK1, VqSERK2, VqSERK3, VqSERK4, and VqSERK5. Analysis of the predicted structures of these SERK proteins revealed they include a signal peptide domain, a leucine zipper domain, a Ser-Pro-Pro domain, a single transmembrane domain, different leucine-rich repeats, and an intracellular kinase activity domain. The SERK genes of grapevine showed different gene expression patterns when treated with powdery mildew (Erysiphe necator) and hormones (salicylic acid, jasmonic acid, abscisic acid, and ethylene). Subcellular localization assays confirmed that VqSERK family proteins localized to the cell membrane. Moreover, we cloned the SERK3/BAK1 gene from the Chinese wild grapevine V. quinquangularis clone 'Shang-24'. Heterologous VqSERK3/BAK1 expression in the Arabidopsis bak1-4 mutant lines restored control of cell death, increased resistance to powdery mildew, and strengthened stomatal immunity. Our work may provide the foundation for further studies of SERK genes for pathogen resistance and hormone treatment in grapevine.
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Affiliation(s)
- Yajuan Li
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Chen Jiao
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Zhenjiang Wei
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Shengyue Chai
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Hui Jia
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Min Gao
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Jessica Allison
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, U.S.A
| | - Zhi Li
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Chang-Bing Song
- College of Biological Science and Engineering, North Minzu University, Yinchuan 750021, P.R. China
| | - Xiping Wang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
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8
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Morales JG, Gaviria AE, Gilchrist E. Allelic Variation and Selection in Effector Genes of Phytophthora infestans (Mont.) de Bary. Pathogens 2020; 9:pathogens9070551. [PMID: 32659973 PMCID: PMC7400436 DOI: 10.3390/pathogens9070551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022] Open
Abstract
Phytophthora infestans is a devastating plant pathogen in several crops such as potato (Solanum tuberosum), tomato (Solanum lycopersicum) and Andean fruits such as tree tomato (Solanum betaceum), lulo (Solanum quitoense), uchuva (Physalis peruviana) and wild species in the genus Solanum sp. Despite intense research performed around the world, P. infestans populations from Colombia, South America, are poorly understood. Of particular importance is knowledge about pathogen effector proteins, which are responsible for virulence. The present work was performed with the objective to analyze gene sequences coding for effector proteins of P. infestans from isolates collected from different hosts and geographical regions. Several genetic parameters, phylogenetic analyses and neutrality tests for non-synonymous and synonymous substitutions were calculated. Non-synonymous substitutions were identified for all genes that exhibited polymorphisms at the DNA level. Significant negative selection values were found for two genes (PITG_08994 and PITG_12737) suggesting active coevolution with the corresponding host resistance proteins. Implications for pathogen virulence mechanisms and disease management are discussed.
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Affiliation(s)
- Juan G. Morales
- Group and Laboratory of Fitotecnia Tropical, Departamento de Ciencias Agronómicas, Facultad de Ciencias Agrarias, Universidad Nacional de Colombia sede Medellín, Medellín, 050034 Antioquia, Colombia; (A.E.G.); (E.G.)
- Correspondence: ; Tel.: +0057-4-4309088
| | - Astrid E. Gaviria
- Group and Laboratory of Fitotecnia Tropical, Departamento de Ciencias Agronómicas, Facultad de Ciencias Agrarias, Universidad Nacional de Colombia sede Medellín, Medellín, 050034 Antioquia, Colombia; (A.E.G.); (E.G.)
| | - Elizabeth Gilchrist
- Group and Laboratory of Fitotecnia Tropical, Departamento de Ciencias Agronómicas, Facultad de Ciencias Agrarias, Universidad Nacional de Colombia sede Medellín, Medellín, 050034 Antioquia, Colombia; (A.E.G.); (E.G.)
- Universidad EAFIT, 050034 Medellín, Colombia
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Mechan Llontop ME, Sharma P, Aguilera Flores M, Yang S, Pollok J, Tian L, Huang C, Rideout S, Heath LS, Li S, Vinatzer BA. Strain-Level Identification of Bacterial Tomato Pathogens Directly from Metagenomic Sequences. PHYTOPATHOLOGY 2020; 110:768-779. [PMID: 31829116 DOI: 10.1094/phyto-09-19-0351-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Routine strain-level identification of plant pathogens directly from symptomatic tissue could significantly improve plant disease control and prevention. Here we tested the Oxford Nanopore Technologies (ONT) MinION sequencer for metagenomic sequencing of tomato plants either artificially inoculated with a known strain of the bacterial speck pathogen Pseudomonas syringae pv. tomato or collected in the field and showing bacterial spot symptoms caused by one of four Xanthomonas species. After species-level identification via ONT's WIMP software and the third-party tools Sourmash and MetaMaps, we used Sourmash and MetaMaps with a custom database of representative genomes of bacterial tomato pathogens to attempt strain-level identification. In parallel, each metagenome was assembled and the longest contigs were used as query with the genome-based microbial identification Web service LINbase. Both the read-based and assembly-based approaches correctly identified P. syringae pv. tomato strain T1 in the artificially inoculated samples. The pathogen strain in most field samples was identified as a member of Xanthomonas perforans group 2. This result was confirmed by whole genome sequencing of colonies isolated from one of the samples. Although in our case metagenome-based pathogen identification at the strain level was achieved, caution still must be exercised in interpreting strain-level results because of the challenges inherent to assigning reads to specific strains and the error rate of nanopore sequencing.
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Affiliation(s)
| | - Parul Sharma
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
- Graduate program in Genetics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, VA
| | - Marcela Aguilera Flores
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
- Graduate program in Genetics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, VA
| | - Shu Yang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
| | - Jill Pollok
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
- Virginia Tech Eastern Shore Agricultural Research and Extension Center, Painter, VA
| | - Long Tian
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
| | - Chenjie Huang
- Department of Computer Sciences, Virginia Tech, Blacksburg, VA
| | - Steve Rideout
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
- Virginia Tech Eastern Shore Agricultural Research and Extension Center, Painter, VA
| | - Lenwood S Heath
- Department of Computer Sciences, Virginia Tech, Blacksburg, VA
| | - Song Li
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
| | - Boris A Vinatzer
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
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10
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Rodríguez M, Torres M, Blanco L, Béjar V, Sampedro I, Llamas I. Plant growth-promoting activity and quorum quenching-mediated biocontrol of bacterial phytopathogens by Pseudomonas segetis strain P6. Sci Rep 2020; 10:4121. [PMID: 32139754 PMCID: PMC7058018 DOI: 10.1038/s41598-020-61084-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/18/2020] [Indexed: 01/18/2023] Open
Abstract
Given the major threat of phytopathogenic bacteria to food production and ecosystem stability worldwide, novel alternatives to conventional chemicals-based agricultural practices are needed to combat these bacteria. The objective of this study is to evaluate the ability of Pseudomonas segetis strain P6, which was isolated from the Salicornia europaea rhizosphere, to act as a potential biocontrol agent given its plant growth-promoting (PGP) and quorum quenching (QQ) activities. Seed biopriming and in vivo assays of tomato plants inoculated with strain P6 resulted in an increase in seedling height and weight. We detected QQ activity, involving enzymatic degradation of signal molecules in quorum sensing communication systems, against a broad range of N-acylhomoserine lactones (AHLs). HPLC-MRM data and phylogenetic analysis indicated that the QQ enzyme was an acylase. The QQ activity of strain P6 reduced soft rot symptoms caused by Dickeya solani, Pectobacterium atrosepticum and P. carotovorum on potato and carrot. In vivo assays showed that the PGP and QQ activities of strain P6 protect tomato plants against Pseudomonas syringae pv. tomato, indicating that strain P6 could have biotechnological applications. To our knowledge, this is the first report to show PGP and QQ activities in an indigenous Pseudomonas strain from Salicornia plants.
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Affiliation(s)
- Miguel Rodríguez
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Marta Torres
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain.,Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain.,Institute for Integrative Biology of the Cell (I2BC), CEA/CNRS/University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, France
| | - Lydia Blanco
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Victoria Béjar
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain.,Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain
| | - Inmaculada Sampedro
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain.
| | - Inmaculada Llamas
- Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain. .,Institute of Biotechnology, Biomedical Research Center (CIBM), University of Granada, Granada, Spain.
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Silencing of Phytopathogen Communication by the Halotolerant PGPR Staphylococcus equorum Strain EN21. Microorganisms 2019; 8:microorganisms8010042. [PMID: 31878301 PMCID: PMC7022284 DOI: 10.3390/microorganisms8010042] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/20/2019] [Accepted: 12/22/2019] [Indexed: 12/16/2022] Open
Abstract
Increasing world food demand together with soil erosion and indiscriminate use of chemical fertilization highlight the need to adopt sustainable crop production strategies. In this context, a combination of plant growth-promoting rhizobacteria (PGPR) and pathogen management represents a sustainable and efficient alternative. Though little studied, halophilic and halotolerant PGPR could be a beneficial plant growth promotion strategy for saline and non-saline soils. The virulence of many bacterial phytopathogens is regulated by quorum sensing (QS) systems. Quorum quenching (QQ) involves the enzymatic degradation of phytopathogen-generated signal molecules, mainly N-acyl homoserine lactones (AHLs). In this study, we investigate plant growth-promoting (PGP) activity and the capacity of the halotolerant bacterium Staphylococcus equorum strain EN21 to attenuate phytopathogens virulence through QQ. We used biopriming and in vivo tomato plant experiments to analyse the PGP activity of strain EN21. AHL inactivation was observed to reduce Pseudomonas syringae pv. tomato infections in tomato and Arabidopsis plants. Our study of Dickeya solani, Pectobacterium carotovorum subsp. carotovorum and Erwinia amylovora bacteria in potato tubers, carrots and pears, respectively, also demonstrated the effectiveness of QS interruption by EN21. Overall, this study highlights the potential of strain S. equorum EN21 in plant growth promotion and QQ-driven bacterial phytopathogen biocontrol.
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12
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Potnis N, Kandel PP, Merfa MV, Retchless AC, Parker JK, Stenger DC, Almeida RPP, Bergsma-Vlami M, Westenberg M, Cobine PA, De La Fuente L. Patterns of inter- and intrasubspecific homologous recombination inform eco-evolutionary dynamics of Xylella fastidiosa. THE ISME JOURNAL 2019; 13:2319-2333. [PMID: 31110262 PMCID: PMC6776109 DOI: 10.1038/s41396-019-0423-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 11/09/2022]
Abstract
High rates of homologous recombination (HR) in the bacterial plant pathogen Xylella fastidiosa have been previously detected. This study aimed to determine the extent and explore the ecological significance of HR in the genomes of recombinants experimentally generated by natural transformation and wild-type isolates. Both sets of strains displayed widespread HR and similar average size of recombined fragments consisting of random events (2-10 kb) of inter- and intrasubspecific recombination. A significantly higher proportion and greater lengths (>10 kb, maximum 31.5 kb) of recombined fragments were observed in subsp. morus and in strains isolated in Europe from intercepted coffee plants shipped from the Americas. Such highly recombinant strains pose a serious risk of emergence of novel variants, as genetically distinct and formerly geographically isolated genotypes are brought in close proximity by global trade. Recently recombined regions in wild-type strains included genes involved in regulation and signaling, host colonization, nutrient acquisition, and host evasion, all fundamental traits for X. fastidiosa ecology. Identification of four recombinant loci shared between wild-type and experimentally generated recombinants suggests potential hotspots of recombination in this naturally competent pathogen. These findings provide insights into evolutionary forces possibly affecting the adaptive potential to colonize the host environments of X. fastidiosa.
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Affiliation(s)
- Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
| | - Prem P Kandel
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, USA
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
| | - Adam C Retchless
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jennifer K Parker
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Drake C Stenger
- United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Maria Bergsma-Vlami
- Dutch National Plant Protection Organization (NPPO-NL), P.O. Box. 9102, Wageningen, 6700 HC, The Netherlands
| | - Marcel Westenberg
- Dutch National Plant Protection Organization (NPPO-NL), P.O. Box. 9102, Wageningen, 6700 HC, The Netherlands
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA.
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13
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Mazo-Molina C, Mainiero S, Hind SR, Kraus CM, Vachev M, Maviane-Macia F, Lindeberg M, Saha S, Strickler SR, Feder A, Giovannoni JJ, Smart CD, Peeters N, Martin GB. The Ptr1 Locus of Solanum lycopersicoides Confers Resistance to Race 1 Strains of Pseudomonas syringae pv. tomato and to Ralstonia pseudosolanacearum by Recognizing the Type III Effectors AvrRpt2 and RipBN. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:949-960. [PMID: 30785360 DOI: 10.1094/mpmi-01-19-0018-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Race 1 strains of Pseudomonas syringae pv. tomato, which cause bacterial speck disease of tomato, are becoming increasingly common and no simply inherited genetic resistance to such strains is known. We discovered that a locus in Solanum lycopersicoides, termed Pseudomonas tomato race 1 (Ptr1), confers resistance to race 1 P. syringae pv. tomato strains by detecting the activity of type III effector AvrRpt2. In Arabidopsis, AvrRpt2 degrades the RIN4 protein, thereby activating RPS2-mediated immunity. Using site-directed mutagenesis of AvrRpt2, we found that, like RPS2, activation of Ptr1 requires AvrRpt2 proteolytic activity. Ptr1 also detected the activity of AvrRpt2 homologs from diverse bacteria, including one in Ralstonia pseudosolanacearum. The genome sequence of S. lycopersicoides revealed no RPS2 homolog in the Ptr1 region. Ptr1 could play an important role in controlling bacterial speck disease and its future cloning may shed light on an example of convergent evolution for recognition of a widespread type III effector.
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Affiliation(s)
- Carolina Mazo-Molina
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
- 2Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Samantha Mainiero
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - Sarah R Hind
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - Christine M Kraus
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - Mishi Vachev
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | | | - Magdalen Lindeberg
- 2Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Surya Saha
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - Susan R Strickler
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - Ari Feder
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - James J Giovannoni
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
- 4Robert W. Holley Center for Agriculture and Health, USDA-ARS, Ithaca, NY 14853, U.S.A
| | - Christine D Smart
- 2Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Nemo Peeters
- 3LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Gregory B Martin
- 1Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
- 2Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
- 5Department of Horticultural Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
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14
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Gerin D, Cariddi C, de Miccolis Angelini RM, Rotolo C, Dongiovanni C, Faretra F, Pollastro S. First Report of Pseudomonas Grapevine Bunch Rot Caused by Pseudomonas syringae pv. syringae. PLANT DISEASE 2019; 103:1954-1960. [PMID: 31169085 DOI: 10.1094/pdis-11-18-1992-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pseudomonas syringae pv. syringae, a Gammaproteobacterium belonging to genomospecies 2 within the P. syringae complex, is distributed worldwide, and it is responsible for bacterial canker on >100 different hosts, including the grapevine. P. syringae pv. syringae induces necrotic lesions in the leaf blades, veins, petioles, shoots, rachis, and tendrils on grapevine cultivars in different areas. P. syringae pv. syringae has been associated with severe economic losses in different grape cultivars in Australia, where it causes inflorescence rot. In midsummer to late summer 2017, symptoms of berry rots differing from those caused by the common berry rots agents were observed in different cultivar Red Globe vineyards of Apulia (southern Italy). As proven by fulfillment of Koch's postulates, these symptoms were caused by a bacterium that, according to the results of biochemical, physiological, nutritional, antimicrobial activity, and pathogenicity tests and sequencing of 16S ribosomal DNA, gyrB, rpoB, and rpoD genes, was identified as P. syringae pv. syringae. This is the first report of Pseudomonas grapevine bunch rot.
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Affiliation(s)
- D Gerin
- 1Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, 70126 Bari, Italy
| | - C Cariddi
- 1Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, 70126 Bari, Italy
| | - R M de Miccolis Angelini
- 1Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, 70126 Bari, Italy
- 2Selge Network, University of Bari Aldo Moro, 70126 Bari, Italy
| | - C Rotolo
- 1Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, 70126 Bari, Italy
| | - C Dongiovanni
- 3Centro di Ricerca, Sperimentazione e Formazione in Agricoltura "Basile Caramia," 70010 Locorotondo, Italy
| | - F Faretra
- 1Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, 70126 Bari, Italy
- 2Selge Network, University of Bari Aldo Moro, 70126 Bari, Italy
| | - S Pollastro
- 1Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, 70126 Bari, Italy
- 2Selge Network, University of Bari Aldo Moro, 70126 Bari, Italy
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15
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Genomic and pathogenic properties of Pseudomonas syringae pv. syringae strains isolated from apricot in East Azerbaijan province, Iran. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.101167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Scotti R, D’Agostino N, Zaccardelli M. Gene expression profiling of tomato roots interacting with Pseudomonas fluorescens unravels the molecular reprogramming that occurs during the early phases of colonization. Symbiosis 2019. [DOI: 10.1007/s13199-019-00611-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Timilsina S, Pereira-Martin JA, Minsavage GV, Iruegas-Bocardo F, Abrahamian P, Potnis N, Kolaczkowski B, Vallad GE, Goss EM, Jones JB. Multiple Recombination Events Drive the Current Genetic Structure of Xanthomonas perforans in Florida. Front Microbiol 2019; 10:448. [PMID: 30930868 PMCID: PMC6425879 DOI: 10.3389/fmicb.2019.00448] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/20/2019] [Indexed: 11/23/2022] Open
Abstract
Prior to the identification of Xanthomonas perforans associated with bacterial spot of tomato in 1991, X. euvesicatoria was the only known species in Florida. Currently, X. perforans is the Xanthomonas sp. associated with tomato in Florida. Changes in pathogenic race and sequence alleles over time signify shifts in the dominant X. perforans genotype in Florida. We previously reported recombination of X. perforans strains with closely related Xanthomonas species as a potential driving factor for X. perforans evolution. However, the extent of recombination across the X. perforans genomes was unknown. We used a core genome multilocus sequence analysis approach to identify conserved genes and evaluated recombination-associated evolution of these genes in X. perforans. A total of 1,356 genes were determined to be "core" genes conserved among the 58 X. perforans genomes used in the study. Our approach identified three genetic groups of X. perforans in Florida based on the principal component analysis (PCA) using core genes. Nucleotide variation in 241 genes defined these groups, that are referred as Phylogenetic-group Defining (PgD) genes. Furthermore, alleles of many of these PgD genes showed 100% sequence identity with X. euvesicatoria, suggesting that variation likely has been introduced by recombination at multiple locations throughout the bacterial chromosome. Site-specific recombinase genes along with plasmid mobilization and phage associated genes were observed at different frequencies in the three phylogenetic groups and were associated with clusters of recombinant genes. Our analysis of core genes revealed the extent, source, and mechanisms of recombination events that shaped the current population and genomic structure of X. perforans in Florida.
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Affiliation(s)
- Sujan Timilsina
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | | | - Gerald V. Minsavage
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | | | - Peter Abrahamian
- Gulf Coast Research and Education Center, University of Florida, Gainesville, FL, United States
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Bryan Kolaczkowski
- Microbiology and Cell Science, University of Florida, Gainesville, FL, United States
| | - Gary E. Vallad
- Gulf Coast Research and Education Center, University of Florida, Gainesville, FL, United States
| | - Erica M. Goss
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
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18
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Recombination of ecologically and evolutionarily significant loci maintains genetic cohesion in the Pseudomonas syringae species complex. Genome Biol 2019; 20:3. [PMID: 30606234 PMCID: PMC6317194 DOI: 10.1186/s13059-018-1606-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 12/06/2018] [Indexed: 01/25/2023] Open
Abstract
Background Pseudomonas syringae is a highly diverse bacterial species complex capable of causing a wide range of serious diseases on numerous agronomically important crops. We examine the evolutionary relationships of 391 agricultural and environmental strains using whole-genome sequencing and evolutionary genomic analyses. Results We describe the phylogenetic distribution of all 77,728 orthologous gene families in the pan-genome, reconstruct the core genome phylogeny using the 2410 core genes, hierarchically cluster the accessory genome, identify the diversity and distribution of type III secretion systems and their effectors, predict ecologically and evolutionary relevant loci, and establish the molecular evolutionary processes operating on gene families. Phylogenetic and recombination analyses reveals that the species complex is subdivided into primary and secondary phylogroups, with the former primarily comprised of agricultural isolates, including all of the well-studied P. syringae strains. In contrast, the secondary phylogroups include numerous environmental isolates. These phylogroups also have levels of genetic diversity typically found among distinct species. An analysis of rates of recombination within and between phylogroups revealed a higher rate of recombination within primary phylogroups than between primary and secondary phylogroups. We also find that “ecologically significant” virulence-associated loci and “evolutionarily significant” loci under positive selection are over-represented among loci that undergo inter-phylogroup genetic exchange. Conclusions While inter-phylogroup recombination occurs relatively rarely, it is an important force maintaining the genetic cohesion of the species complex, particularly among primary phylogroup strains. This level of genetic cohesion, and the shared plant-associated niche, argues for considering the primary phylogroups as a single biological species. Electronic supplementary material The online version of this article (10.1186/s13059-018-1606-y) contains supplementary material, which is available to authorized users.
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19
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Dutta B, Gitaitis R, Agarwal G, Coutinho T, Langston D. Pseudomonas coronafaciens sp. nov., a new phytobacterial species diverse from Pseudomonas syringae. PLoS One 2018; 13:e0208271. [PMID: 30521563 PMCID: PMC6283537 DOI: 10.1371/journal.pone.0208271] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/14/2018] [Indexed: 11/19/2022] Open
Abstract
We propose Pseudomonas coronafaciens sp. nov. as a new species in genus Pseudomonas, which is diverse from P. syringae. We also classified strains from onions which are responsible for yellow bud (YB) disease as P. coronafaciens. Sequencing of 16S rRNA gene and multi-locus sequence analysis (MLSA) of housekeeping genes (gyrB, rpoD, gltA and gap1 genes) for the P. syringae pv. coronafaciens strains along with other strains of P. syringae pathovars resulted in a distinct cluster separate from other P. syringae pathovars. Based on DNA-DNA relatedness, pathotype strain of P. syringae pv. coronafaciens (CFBP 2216PT) exhibited ≤35.5% similarity with the pathotype strains of P. syringae pv. syringae (CFBP 1392PT, 4702T) but exhibited ≥90.6% with the YB strains (YB 12-1, YB 12-4, YB 09-1). Also, the YB strains (YB 12-1, YB 12-4, YB 09-1) were able to infect only onion but not oat, rye and Italian ryegrass (common hosts for P. syrinage pv. coronafaciens). Contrastingly, P. syringae pv. coronafaciens strains (NCPPB 600PT, ATCC 19608, Pcf 83-300) produced typical halo blight symptoms on oat, rye and Italian rye grass but did not produce any symptoms on onion. These results provide evidence that P. syringae pv. coronafaciens should be elevated to a species level and the new YB strains may potentially be a novel pathovar of hereto proposed P. coronafaciens species.
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Affiliation(s)
- Bhabesh Dutta
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA, United States of America
| | - Ronald Gitaitis
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA, United States of America
| | - Gaurav Agarwal
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA, United States of America
| | - Teresa Coutinho
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - David Langston
- Department of Plant Pathology, Physiology and Weed Science, Tidewater Agricultural Research and Extension Center, Virginia Tech, Suffolk, VA, United States of America
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20
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Zeng Q, Cui Z, Wang J, Childs KL, Sundin GW, Cooley DR, Yang C, Garofalo E, Eaton A, Huntley RB, Yuan X, Schultes NP. Comparative genomics of Spiraeoideae-infecting Erwinia amylovora strains provides novel insight to genetic diversity and identifies the genetic basis of a low-virulence strain. MOLECULAR PLANT PATHOLOGY 2018; 19:1652-1666. [PMID: 29178620 PMCID: PMC6638132 DOI: 10.1111/mpp.12647] [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: 09/01/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 05/24/2023]
Abstract
Erwinia amylovora is the causal agent of fire blight, one of the most devastating diseases of apple and pear. Erwinia amylovora is thought to have originated in North America and has now spread to at least 50 countries worldwide. An understanding of the diversity of the pathogen population and the transmission to different geographical regions is important for the future mitigation of this disease. In this research, we performed an expanded comparative genomic study of the Spiraeoideae-infecting (SI) E. amylovora population in North America and Europe. We discovered that, although still highly homogeneous, the genetic diversity of 30 E. amylovora genomes examined was about 30 times higher than previously determined. These isolates belong to four distinct clades, three of which display geographical clustering and one of which contains strains from various geographical locations ('Widely Prevalent' clade). Furthermore, we revealed that strains from the Widely Prevalent clade displayed a higher level of recombination with strains from a clade strictly from the eastern USA, which suggests that the Widely Prevalent clade probably originated from the eastern USA before it spread to other locations. Finally, we detected variations in virulence in the SI E. amylovora strains on immature pear, and identified the genetic basis of one of the low-virulence strains as being caused by a single nucleotide polymorphism in hfq, a gene encoding an important virulence regulator. Our results provide insights into the population structure, distribution and evolution of SI E. amylovora in North America and Europe.
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Affiliation(s)
- Quan Zeng
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew Haven 06511CTUSA
| | - Zhouqi Cui
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew Haven 06511CTUSA
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukee 53211WIUSA
| | - Jie Wang
- Department of Plant BiologyMichigan State UniversityEast Lansing 48824MIUSA
| | - Kevin L. Childs
- Department of Plant BiologyMichigan State UniversityEast Lansing 48824MIUSA
| | - George W. Sundin
- Department of Plant, Soil, and Microbial SciencesMichigan State UniversityEast Lansing 48824MIUSA
| | - Daniel R. Cooley
- Stockbridge School of AgricultureUniversity of MassachusettsAmherst 01003MAUSA
| | - Ching‐Hong Yang
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukee 53211WIUSA
| | - Elizabeth Garofalo
- Stockbridge School of AgricultureUniversity of MassachusettsAmherst 01003MAUSA
| | - Alan Eaton
- Department of Agriculture, Nutrition, and Food SystemsUniversity of New HampshireDurham 03824NHUSA
| | - Regan B. Huntley
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew Haven 06511CTUSA
| | - Xiaochen Yuan
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukee 53211WIUSA
| | - Neil P. Schultes
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew Haven 06511CTUSA
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21
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Zeng Q, Wang J, Bertels F, Giordano PR, Chilvers MI, Huntley RB, Vargas JM, Sundin GW, Jacobs JL, Yang CH. Recombination of Virulence Genes in Divergent Acidovorax avenae Strains That Infect a Common Host. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:813-828. [PMID: 28682158 DOI: 10.1094/mpmi-06-17-0151-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Bacterial etiolation and decline (BED), caused by Acidovorax avenae, is an emerging disease of creeping bentgrass on golf courses in the United States. We performed the first comprehensive analysis of A. avenae on a nationwide collection of turfgrass- and maize-pathogenic A. avenae. Surprisingly, our results reveal that the turfgrass-pathogenic A. avenae in North America are not only highly divergent but also belong to two distinct phylogroups. Both phylogroups specifically infect turfgrass but are more closely related to maize pathogens than to each other. This suggests that, although the disease is only recently reported, it has likely been infecting turfgrass for a long time. To identify a genetic basis for the host specificity, we searched for genes closely related among turfgrass strains but distantly related to their homologs from maize strains. We found a cluster of 11 such genes generated by three ancient recombination events within the type III secretion system (T3SS) pathogenicity island. Ever since the recombination, the cluster has been conserved by strong purifying selection, hinting at its selective importance. Together our analyses suggest that BED is an ancient disease that may owe its host specificity to a highly conserved cluster of 11 T3SS genes.
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Affiliation(s)
- Quan Zeng
- 1 Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, U.S.A
| | - Jie Wang
- 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Frederic Bertels
- 3 Department for Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany; and
| | - Paul R Giordano
- 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Martin I Chilvers
- 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Regan B Huntley
- 1 Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, U.S.A
| | - Joseph M Vargas
- 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - George W Sundin
- 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Janette L Jacobs
- 2 Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Ching-Hong Yang
- 4 Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
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22
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Arenas M, Araujo NM, Branco C, Castelhano N, Castro-Nallar E, Pérez-Losada M. Mutation and recombination in pathogen evolution: Relevance, methods and controversies. INFECTION GENETICS AND EVOLUTION 2017; 63:295-306. [PMID: 28951202 DOI: 10.1016/j.meegid.2017.09.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
Abstract
Mutation and recombination drive the evolution of most pathogens by generating the genetic variants upon which selection operates. Those variants can, for example, confer resistance to host immune systems and drug therapies or lead to epidemic outbreaks. Given their importance, diverse evolutionary studies have investigated the abundance and consequences of mutation and recombination in pathogen populations. However, some controversies persist regarding the contribution of each evolutionary force to the development of particular phenotypic observations (e.g., drug resistance). In this study, we revise the importance of mutation and recombination in the evolution of pathogens at both intra-host and inter-host levels. We also describe state-of-the-art analytical methodologies to detect and quantify these two evolutionary forces, including biases that are often ignored in evolutionary studies. Finally, we present some of our former studies involving pathogenic taxa where mutation and recombination played crucial roles in the recovery of pathogenic fitness, the generation of interspecific genetic diversity, or the design of centralized vaccines. This review also illustrates several common controversies and pitfalls in the analysis and in the evaluation and interpretation of mutation and recombination outcomes.
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Affiliation(s)
- Miguel Arenas
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, Spain; Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Natalia M Araujo
- Laboratory of Molecular Virology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.
| | - Catarina Branco
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Nadine Castelhano
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Eduardo Castro-Nallar
- Universidad Andrés Bello, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biológicas, Santiago, Chile.
| | - Marcos Pérez-Losada
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Ashburn, VA 20147, Washington, DC, United States; CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão 4485-661, Portugal.
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Characterization and assessment of two biocontrol bacteria against Pseudomonas syringae wilt in Solanum lycopersicum and its genetic responses. Microbiol Res 2017; 206:43-49. [PMID: 29146259 DOI: 10.1016/j.micres.2017.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/08/2017] [Accepted: 09/09/2017] [Indexed: 11/22/2022]
Abstract
Pseudomonas and Bacillus species are attractive due to their potential bio-control application against plant bacterial pathogens. Pseudomonas aeruginosa strain D4 and Bacillus stratosphericus strain FW3 were isolated from mine tailings in South Korea. In these potent bacterial strains, we observed improved antagonistic activity against Pseudomonas syringae DC3000. These strains produced biocatalysts for plant growth promotion, and in vivo examination of Solanum lycopersicum included analysis of disease severity, ion leakage, chlorophyll content, and H2O2 detection. In addition, regulation of the defense genes pathogen-related protein 1a (PR1a) and phenylalanine ammonia lyase (PAL) was compared with treated plants and untreated control plants. The results suggest that these two bacterial strains provide protection against plant pathogens via direct and indirect modes of action and could be used as a bio-control agent.
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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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Baltrus DA, McCann HC, Guttman DS. Evolution, genomics and epidemiology of Pseudomonas syringae: Challenges in Bacterial Molecular Plant Pathology. MOLECULAR PLANT PATHOLOGY 2017; 18:152-168. [PMID: 27798954 PMCID: PMC6638251 DOI: 10.1111/mpp.12506] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 05/12/2023]
Abstract
A remarkable shift in our understanding of plant-pathogenic bacteria is underway. Until recently, nearly all research on phytopathogenic bacteria was focused on a small number of model strains, which provided a deep, but narrow, perspective on plant-microbe interactions. Advances in genome sequencing technologies have changed this by enabling the incorporation of much greater diversity into comparative and functional research. We are now moving beyond a typological understanding of a select collection of strains to a more generalized appreciation of the breadth and scope of plant-microbe interactions. The study of natural populations and evolution has particularly benefited from the expansion of genomic data. We are beginning to have a much deeper understanding of the natural genetic diversity, niche breadth, ecological constraints and defining characteristics of phytopathogenic species. Given this expanding genomic and ecological knowledge, we believe the time is ripe to evaluate what we know about the evolutionary dynamics of plant pathogens.
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Affiliation(s)
| | - Honour C. McCann
- New Zealand Institute for Advanced StudyMassey UniversityAuckland 0632New Zealand
| | - David S. Guttman
- Department of Cell and Systems BiologyUniversity of TorontoTorontoON M5S 3B2Canada
- Centre for the Analysis of Genome Evolution and FunctionUniversity of TorontoTorontoON M5S 3B2Canada
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26
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Fayette J, Raid R, Roberts PD, Jones JB, Pernezny K, Bull CT, Goss EM. Multilocus Sequence Typing of Strains of Bacterial Spot of Lettuce Collected in the United States. PHYTOPATHOLOGY 2016; 106:1262-1269. [PMID: 27359264 DOI: 10.1094/phyto-11-15-0302-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Studies on genetic diversity and recombination in bacterial pathogens are providing a better understanding of the mechanisms shaping bacterial diversity, which can affect disease control. Xanthomonas campestris pv. vitians, causal agent of bacterial leaf spot of lettuce, is a threat to the worldwide lettuce industry. We examined the genetic variation within a sample of 83 strains from California, Florida, and Ohio using multilocus sequence typing of six housekeeping genes, totaling 2.7 kb. Additionally, polymorphism in two virulence-related genes, hrpB2 and a putative glycosyl hydrolase, were examined. Based on housekeeping genes, we found three genetic groups of strains that were all able to induce the disease. These included strains collected from weeds and irrigation water that had haplotypes identical to strains from diseased lettuce. High linkage disequilibrium across the sequenced loci indicates that the pathogen is predominantly clonal but recombination has contributed to the observed sequence variation. Although there was significant genetic variation in X. campestris pv. vitians within and among sampled states, identical haplotypes were observed across all three states. This finding suggests that seedborne inoculum may contribute to the diversity of X. campestris pv. vitians in the United States. Knowledge of the genetic structure of the pathogen may be used for developing resistant lettuce varieties.
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Affiliation(s)
- Joubert Fayette
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
| | - Richard Raid
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
| | - Pamela D Roberts
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
| | - Jeffrey B Jones
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
| | - Ken Pernezny
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
| | - Carolee T Bull
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
| | - Erica M Goss
- First, second, and fifth authors: Everglades Research and Education Center, University of Florida Institute of Food and Agricultural Sciences (IFAS), Belle Glade; third author: Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee; first, second, third, fourth, fifth, and seventh authors: Department of Plant Pathology, University of Florida, Gainesville; sixth author: United States Department of Agriculture-Agricultural Research Service, Pacific West Area, 1636 E. Alisal St., Salinas, CA; and seventh author: Emerging Pathogens Institute, University of Florida, Gainesville
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Clarke CR, Hayes BW, Runde BJ, Markel E, Swingle BM, Vinatzer BA. Comparative genomics of Pseudomonas syringae pathovar tomato reveals novel chemotaxis pathways associated with motility and plant pathogenicity. PeerJ 2016; 4:e2570. [PMID: 27812402 PMCID: PMC5088630 DOI: 10.7717/peerj.2570] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/15/2016] [Indexed: 11/20/2022] Open
Abstract
The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, to replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacteria use chemical-directed regulation of flagellar rotation, a process known as chemotaxis, to move towards favorable environmental conditions. Chemotactic sensing of the plant surface is a potential mechanism through which foliar plant pathogens home in on wounds or stomata, but chemotactic systems in foliar plant pathogens are not well characterized. Comparative genomics of the plant pathogen Pseudomonas syringae pathovar tomato (Pto) implicated annotated chemotaxis genes in the recent adaptations of one Pto lineage. We therefore characterized the chemosensory system of Pto. The Pto genome contains two primary chemotaxis gene clusters, che1 and che2. The che2 cluster is flanked by flagellar biosynthesis genes and similar to the canonical chemotaxis gene clusters of other bacteria based on sequence and synteny. Disruption of the primary phosphorelay kinase gene of the che2 cluster, cheA2, eliminated all swimming and surface motility at 21 °C but not 28 °C for Pto. The che1 cluster is located next to Type IV pili biosynthesis genes but disruption of cheA1 has no observable effect on twitching motility for Pto. Disruption of cheA2 also alters in planta fitness of the pathogen with strains lacking functional cheA2 being less fit in host plants but more fit in a non-host interaction.
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Affiliation(s)
- Christopher R Clarke
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
| | - Byron W Hayes
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
| | - Brendan J Runde
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
| | - Eric Markel
- Emerging Pests and Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, United States Department of Agriculture , Ithaca , NY , USA
| | - Bryan M Swingle
- Emerging Pests and Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, United States Department of Agriculture, Ithaca, NY, USA; Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell, Ithaca, NY, USA
| | - Boris A Vinatzer
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
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Monteil CL, Yahara K, Studholme DJ, Mageiros L, Méric G, Swingle B, Morris CE, Vinatzer BA, Sheppard SK. Population-genomic insights into emergence, crop adaptation and dissemination of Pseudomonas syringae pathogens. Microb Genom 2016; 2:e000089. [PMID: 28348830 PMCID: PMC5359406 DOI: 10.1099/mgen.0.000089] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/13/2016] [Indexed: 12/24/2022] Open
Abstract
Many bacterial pathogens are well characterized but, in some cases, little is known about the populations from which they emerged. This limits understanding of the molecular mechanisms underlying disease. The crop pathogen Pseudomonas syringae sensu lato has been widely isolated from the environment, including wild plants and components of the water cycle, and causes disease in several economically important crops. Here, we compared genome sequences of 45 P. syringae crop pathogen outbreak strains with 69 closely related environmental isolates. Phylogenetic reconstruction revealed that crop pathogens emerged many times independently from environmental populations. Unexpectedly, differences in gene content between environmental populations and outbreak strains were minimal with most virulence genes present in both. However, a genome-wide association study identified a small number of genes, including the type III effector genes hopQ1 and hopD1, to be associated with crop pathogens, but not with environmental populations, suggesting that this small group of genes may play an important role in crop disease emergence. Intriguingly, genome-wide analysis of homologous recombination revealed that the locus Psyr 0346, predicted to encode a protein that confers antibiotic resistance, has been frequently exchanged among lineages and thus may contribute to pathogen fitness. Finally, we found that isolates from diseased crops and from components of the water cycle, collected during the same crop disease epidemic, form a single population. This provides the strongest evidence yet that precipitation and irrigation water are an overlooked inoculum source for disease epidemics caused by P. syringae.
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Affiliation(s)
- Caroline L Monteil
- 4Laboratoire de Bioénergétique Cellulaire, Institut de Biosciences et Biotechnologies d'Aix-Marseille, CEA, 13108, Saint-Paul-lès-Durance, France.,3INRA, UR0407 Pathologie Végétale, Montfavet cedex, France.,1Institute of Life Science, College of Medicine, Swansea University, Swansea, UK.,2Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, USA
| | - Koji Yahara
- 1Institute of Life Science, College of Medicine, Swansea University, Swansea, UK.,5National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Leonardos Mageiros
- 1Institute of Life Science, College of Medicine, Swansea University, Swansea, UK
| | - Guillaume Méric
- 7The Milner Centre for Evolution, Department of Biology and Biotechnology, University of Bath, Claverton Down, Bath, UK
| | - Bryan Swingle
- 8School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
| | - Cindy E Morris
- 3INRA, UR0407 Pathologie Végétale, Montfavet cedex, France
| | - Boris A Vinatzer
- 2Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, USA
| | - Samuel K Sheppard
- 7The Milner Centre for Evolution, Department of Biology and Biotechnology, University of Bath, Claverton Down, Bath, UK.,9Department of Zoology, University of Oxford, Oxford, UK
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Kuzmanović N, Biondi E, Bertaccini A, Obradović A. Genetic relatedness and recombination analysis of Allorhizobium vitis strains associated with grapevine crown gall outbreaks in Europe. J Appl Microbiol 2015; 119:786-96. [PMID: 26032990 DOI: 10.1111/jam.12858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 05/21/2015] [Accepted: 05/21/2015] [Indexed: 11/27/2022]
Abstract
AIMS To analyse genetic diversity and epidemiological relationships among 54 strains of Allorhizobium vitis isolated in Europe during an 8-year period and to assess the relative contribution of mutation and recombination in shaping their diversity. METHODS AND RESULTS By using random amplified polymorphic DNA (RAPD) PCR, strains studied were distributed into 12 genetic groups. Sequence analysis of dnaK, gyrB and recA housekeeping genes was employed to characterize a representative subcollection of 28 strains. A total of 15 different haplotypes were found. Nucleotide sequence analysis suggested the presence of recombination events in A. vitis, particularly affecting dnaK locus. Although prevalence of mutation over recombination was found, impact of recombination was about two times greater than mutation in the evolution of the housekeeping genes analysed. CONCLUSIONS The RAPD analysis indicated high degree of genetic diversity among the strains. However, the most abundant RAPD group was composed of 35 strains, which could lead to the conclusion that they share a common origin and were distributed by the movement of infected grapevine planting material as a most common way of crossing long distances. Furthermore, it seems that recombination is acting as an important driving force in the evolution of A. vitis. As no substantial evidence of recombination was detected within recA gene fragment, this phylogenetic marker could be reliable to characterize phylogenetic relationships among A. vitis strains. SIGNIFICANCE AND IMPACT OF THE STUDY We demonstrated clear epidemiological relationship between majority of strains studied, suggesting a need for more stringent phytosanitary measures in international trade. Moreover, this is the first study to report recombination in A. vitis.
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Affiliation(s)
- N Kuzmanović
- University of Belgrade-Faculty of Agriculture, Belgrade, Serbia
| | - E Biondi
- Department of Agricultural Sciences, University of Bologna, Bologna, Italy
| | - A Bertaccini
- Department of Agricultural Sciences, University of Bologna, Bologna, Italy
| | - A Obradović
- University of Belgrade-Faculty of Agriculture, Belgrade, Serbia
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30
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Jones LA, Saha S, Collmer A, Smart CD, Lindeberg M. Genome-Assisted Development of a Diagnostic Protocol for Distinguishing High Virulence Pseudomonas syringae pv. tomato Strains. PLANT DISEASE 2015; 99:527-534. [PMID: 30699553 DOI: 10.1094/pdis-08-14-0833-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A severe outbreak of bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, occurred in central New York in 2009. Isolate 09150, collected from this outbreak and subsequently named NYS-T1, was found to be highly virulent on tomato. To better understand the relationship of 09150 to other P. syringae strains and develop a diagnostic assay for aggressive strains of this pathogen, the 09150 genome was sequenced. Genome comparison revealed it to be highly similar to a previously sequenced isolate, T1. Genetic factors linked to host interaction including type III effectors, toxin biosynthetic genes, and elicitors of host innate immunity were identified. Type III effector repertoires were compared with other strains in the high virulence T1-like subgroup and lower virulence DC3000/P. syringae pv. maculicola subgroup within P. syringae phylogenetic Group I. Primers for conventional PCR were developed using sequences for avrA, hopW, conserved in the former subgroup and hopN, present in the latter. These were tested on isolates in the two subgroups, other pseudomonads, and other bacterial pathogens of tomato. Primers developed for avaA and hopW were diagnostic for more virulent strains of P. syringae pv. tomato while primers for hopN were diagnostic for P. syringae pv. tomato DC3000 and related P. syringe pv. maculicola strains. Primers designed against hopR distinguished both of these P. syringae subgroups from other P. syringae strains.
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Affiliation(s)
- Lisa A Jones
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456
| | - Surya Saha
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14850; and Boyce Thompson Institute for Plant Research, Ithaca, NY 14853
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14850
| | - Christine D Smart
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456
| | - Magdalen Lindeberg
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14850
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Clarke CR, Hayes BW, Runde BJ, Wicker E, Vinatzer BA. Eggplant and related species are promising genetic resources to dissect the plant immune response to Pseudomonas syringae and Xanthomonas euvesicatoria and to identify new resistance determinants. MOLECULAR PLANT PATHOLOGY 2014; 15:814-822. [PMID: 24684604 PMCID: PMC6638909 DOI: 10.1111/mpp.12140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The apparent lack of durability of many resistance (R) genes highlights the need for the constant identification of new genetic sources of resistance for the breeding of new disease-resistant crop cultivars. To this end, we screened a collection of accessions of eggplant and close relatives for resistance against Pseudomonas syringae pv. tomato (Pto) and Xanthomonas euvesicatoria (Xeu), foliar plant pathogens of many solanaceous crops. Both pathogens caused substantial disease on most genotypes of eggplant and its relatives. Promisingly, however, some of the genotypes were fully or partially resistant to either of the pathogens, suggesting the presence of effective resistance determinants in these genotypes. Segregation of resistance to the growth of Xeu following infiltration in F2 progeny from a cross of a resistant and susceptible genotype suggests that resistance to Xeu is inherited as a multigenic trait. With regard to Pto, a mutant strain lacking all 28 functional type III secreted effectors, and a Pseudomonas fluorescens strain expressing a P. syringae type III secretion system (T3SS), both elicit a strong cell death response on most eggplant lines. Several genotypes thus appear to harbour a mechanism for the direct recognition of a component of the T3SS. Therefore, eggplant and its close relatives are promising resources to unravel novel aspects of plant immunity and to identify new candidate R genes that could be employed in other Solanaceae in which Xeu and Pto cause agriculturally relevant diseases.
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Affiliation(s)
- Christopher R Clarke
- Department of Plant Pathology, Physiology, and Weed Sciences, Virginia Tech, 537 Latham Hall, West Campus Drive, Blacksburg, VA, 24061, USA
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Veluchamy S, Hind SR, Dunham DM, Martin GB, Panthee DR. Natural variation for responsiveness to flg22, flgII-28, and csp22 and Pseudomonas syringae pv. tomato in heirloom tomatoes. PLoS One 2014; 9:e106119. [PMID: 25180693 PMCID: PMC4152135 DOI: 10.1371/journal.pone.0106119] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/28/2014] [Indexed: 11/26/2022] Open
Abstract
Tomato (Solanum lycopersicum L.) is susceptible to many diseases including bacterial speck caused by Pseudomonas syringae pv. tomato. Bacterial speck disease is a serious problem worldwide in tomato production areas where moist conditions and cool temperatures occur. To enhance breeding of speck resistant fresh-market tomato cultivars we identified a race 0 field isolate, NC-C3, of P. s. pv. tomato in North Carolina and used it to screen a collection of heirloom tomato lines for speck resistance in the field. We observed statistically significant variation among the heirloom tomatoes for their response to P. s. pv. tomato NC-C3 with two lines showing resistance approaching a cultivar that expresses the Pto resistance gene, although none of the heirloom lines have Pto. Using an assay that measures microbe-associated molecular pattern (MAMP)-induced production of reactive oxygen species (ROS), we investigated whether the heirloom lines showed differential responsiveness to three bacterial-derived peptide MAMPs: flg22 and flgII-28 (from flagellin) and csp22 (from cold shock protein). Significant differences were observed for MAMP responsiveness among the lines, although these differences did not correlate strongly with resistance or susceptibility to bacterial speck disease. The identification of natural variation for MAMP responsiveness opens up the possibility of using a genetic approach to identify the underlying loci and to facilitate breeding of cultivars with enhanced disease resistance. Towards this goal, we discovered that responsiveness to csp22 segregates as a single locus in an F2 population of tomato.
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Affiliation(s)
- Selvakumar Veluchamy
- Department of Horticultural Science, North Carolina State University, Mountain Horticultural Crops Research and Extension Center, Mills River, North Carolina, United States of America
| | - Sarah R. Hind
- Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America
| | - Diane M. Dunham
- Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America
| | - Gregory B. Martin
- Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Dilip R. Panthee
- Department of Horticultural Science, North Carolina State University, Mountain Horticultural Crops Research and Extension Center, Mills River, North Carolina, United States of America
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James M, Melcher U, Fletcher J. Evaluating the impacts of stressors of Pseudomonas syringae pathovar tomato on the effectiveness of multi-locus variable number tandem repeat analysis and multi-locus sequence typing in microbial forensic investigations. INVESTIGATIVE GENETICS 2014; 5:10. [PMID: 25132953 PMCID: PMC4133955 DOI: 10.1186/2041-2223-5-10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 07/14/2014] [Indexed: 12/02/2022]
Abstract
BACKGROUND Crops in the USA are vulnerable to natural and criminal threats because of their widespread cultivation and lack of surveillance, and because of implementation of growing practices such as monoculture. To prepare for investigation and attribution of such events, forensic assays, including determination of molecular profiles, are being adapted for use with plant pathogens. The use of multi-locus variable number tandem repeat (VNTR) analysis (MLVA) and multi-locus sequence typing (MLST) in investigations involving plant pathogens may be problematic because the long lag periods between pathogen introduction and discovery of associated disease may provide enough time for evolution to occur in the regions of the genome employed in each assay. Thus, more information on the stability of the loci employed in these methods is needed. RESULTS The MLVA fingerprints and MLST profiles were consistent throughout the experiment, indicating that, using a specific set of primers and conditions, MLVA and MLST typing systems reliably identify P.s. tomato DC3000. This information is essential to forensic investigators in interpreting comparisons between MLVA and MLST typing profiles observed in P.s. tomato isolates. CONCLUSIONS Our results indicate that MLVA and MLST typing systems, utilizing the specified primers and conditions, could be employed successfully in forensics investigations involving P.s. tomato. Similar experiments should be conducted in the field and with other high-consequence plant pathogens to ensure that the assays are reliable for pathogens infecting plants in their natural environment and for organisms that may display faster rates of mutation.
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Affiliation(s)
- Mindy James
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater 74078, OK, USA
| | - Ulrich Melcher
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater 74078, OK, USA
| | - Jacqueline Fletcher
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater 74078, OK, USA
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Nunney L, Schuenzel EL, Scally M, Bromley RE, Stouthamer R. Large-scale intersubspecific recombination in the plant-pathogenic bacterium Xylella fastidiosa is associated with the host shift to mulberry. Appl Environ Microbiol 2014; 80:3025-33. [PMID: 24610840 PMCID: PMC4018926 DOI: 10.1128/aem.04112-13] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/27/2014] [Indexed: 11/20/2022] Open
Abstract
Homologous recombination plays an important role in the structuring of genetic variation of many bacteria; however, its importance in adaptive evolution is not well established. We investigated the association of intersubspecific homologous recombination (IHR) with the shift to a novel host (mulberry) by the plant-pathogenic bacterium Xylella fastidiosa. Mulberry leaf scorch was identified about 25 years ago in native red mulberry in the eastern United States and has spread to introduced white mulberry in California. Comparing a sequence of 8 genes (4,706 bp) from 21 mulberry-type isolates to published data (352 isolates representing all subspecies), we confirmed previous indications that the mulberry isolates define a group distinct from the 4 subspecies, and we propose naming the taxon X. fastidiosa subsp. morus. The ancestry of its gene sequences was mixed, with 4 derived from X. fastidiosa subsp. fastidiosa (introduced from Central America), 3 from X. fastidiosa subsp. multiplex (considered native to the United States), and 1 chimeric, demonstrating that this group originated by large-scale IHR. The very low within-type genetic variation (0.08% site polymorphism), plus the apparent inability of native X. fastidiosa subsp. multiplex to infect mulberry, suggests that this host shift was achieved after strong selection acted on genetic variants created by IHR. Sequence data indicate that a single ancestral IHR event gave rise not only to X. fastidiosa subsp. morus but also to the X. fastidiosa subsp. multiplex recombinant group which infects several hosts but is the only type naturally infecting blueberry, thus implicating this IHR in the invasion of at least two novel native hosts, mulberry and blueberry.
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Affiliation(s)
- Leonard Nunney
- Department of Biology, University of California, Riverside, California, USA
| | - Erin L. Schuenzel
- Department of Biology, University of Texas—Pan American, Edinburg, Texas, USA
| | - Mark Scally
- Department of Biology, University of Texas—Pan American, Edinburg, Texas, USA
| | - Robin E. Bromley
- Department of Entomology, University of California, Riverside, California, USA
| | - Richard Stouthamer
- Department of Entomology, University of California, Riverside, California, 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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Vinatzer BA, Monteil CL, Clarke CR. Harnessing population genomics to understand how bacterial pathogens emerge, adapt to crop hosts, and disseminate. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:19-43. [PMID: 24820995 DOI: 10.1146/annurev-phyto-102313-045907] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Crop diseases emerge without warning. In many cases, diseases cross borders, or even oceans, before plant pathologists have time to identify and characterize the causative agents. Genome sequencing, in combination with intensive sampling of pathogen populations and application of population genetic tools, is now providing the means to unravel how bacterial crop pathogens emerge from environmental reservoirs, how they evolve and adapt to crops, and what international and intercontinental routes they follow during dissemination. Here, we introduce the field of population genomics and review the population genomics research of bacterial plant pathogens over the past 10 years. We highlight the potential of population genomics for investigating plant pathogens, using examples of population genomics studies of human pathogens. We also describe the complementary nature of the fields of population genomics and molecular plant-microbe interactions and propose how to translate new insights into improved disease prevention and control.
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Affiliation(s)
- Boris A Vinatzer
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, Virginia 24061; ,
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Huang CH, Vallad GE, Adkison H, Summers C, Margenthaler E, Schneider C, Hong J, Jones JB, Ong K, Norman DJ. A Novel Xanthomonas sp. Causes Bacterial Spot of Rose (Rosa spp.). PLANT DISEASE 2013; 97:1301-1307. [PMID: 30722131 DOI: 10.1094/pdis-09-12-0851-re] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A bacterial spot of rose (Rosa spp.) caused by a xanthomonad was observed in Florida and Texas. Ten representative strains collected from the two states between 2004 and 2010 were used to determine the taxonomic position of this rose pathogen. Fatty acid methyl ester analysis was performed and a nearly 2-kb 16S-23S rRNA intergenic spacer along with flanking portions of the 16S and 23S rRNA genes were sequenced for selected strains, showing that they were members of the genus Xanthomonas. Multilocus sequence typing and analysis (MLST/MLSA) and pathogenicity tests were conducted to further characterize the Xanthomonas strains. The MLSA, based on six gene fragments-fusA, gapA, gltA, gyrB, lacF, and lepA-showed that the rose strains fell into Xanthomonas axonopodis subgroup 9.2 and shared the highest similarity values (98.8 to 99.7%) with X. alfalfae subsp. citrumelonis of the subgroup. However, principal coordinate analysis grouped the rose strains into a unique cluster distinct from other members of the subgroup according to virulence phenotypes on 11 plant species belonging to five plant families (Araceae, Euphorbiaceae, Rosaceae, Rutaceae, and Solanaceae). Moreover, the rose strains were aggressive on rose and Indian Hawthorn (Rhaphiolepsis indica). On the basis of the MLSA and virulence phenotypes, the pathovar epithet rosa is proposed.
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Affiliation(s)
- Cheng-Hua Huang
- Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598
| | - Gary E Vallad
- Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598
| | - Heather Adkison
- Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598
| | - Carly Summers
- Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598
| | - Elaina Margenthaler
- Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598
| | - Christina Schneider
- Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598
| | - Jason Hong
- Department of Plant Pathology, University of Florida, Gainesville 32611
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville 32611
| | - Kevin Ong
- Texas Plant Disease Diagnostic Lab, Texas A&M University, College Station 77845
| | - David J Norman
- Mid-Florida Research and Education Center, University of Florida, IFAS, Apopka 32703
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Monteil CL, Cai R, Liu H, Llontop MEM, Leman S, Studholme DJ, Morris CE, Vinatzer BA. Nonagricultural reservoirs contribute to emergence and evolution of Pseudomonas syringae crop pathogens. THE NEW PHYTOLOGIST 2013; 199:800-11. [PMID: 23692644 DOI: 10.1111/nph.12316] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/02/2013] [Indexed: 05/10/2023]
Abstract
While the existence of environmental reservoirs of human pathogens is well established, less is known about the role of nonagricultural environments in emergence, evolution, and spread of crop pathogens. Here, we analyzed phylogeny, virulence genes, host range, and aggressiveness of Pseudomonas syringae strains closely related to the tomato pathogen P. syringae pv. tomato (Pto), including strains isolated from snowpack and streams. The population of Pto relatives in nonagricultural environments was estimated to be large and its diversity to be higher than that of the population of Pto and its relatives on crops. Ancestors of environmental strains, Pto, and other genetically monomorphic crop pathogens were inferred to have frequently recombined, suggesting an epidemic population structure for P. syringae. Some environmental strains have repertoires of type III-secreted effectors very similar to Pto, are almost as aggressive on tomato as Pto, but have a wider host range than typical Pto strains. We conclude that crop pathogens may have evolved through a small number of evolutionary events from a population of less aggressive ancestors with a wider host range present in nonagricultural environments.
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Affiliation(s)
- Caroline L Monteil
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, USA
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Mhedbi-Hajri N, Hajri A, Boureau T, Darrasse A, Durand K, Brin C, Saux MFL, Manceau C, Poussier S, Pruvost O, Lemaire C, Jacques MA. Evolutionary history of the plant pathogenic bacterium Xanthomonas axonopodis. PLoS One 2013; 8:e58474. [PMID: 23505513 PMCID: PMC3591321 DOI: 10.1371/journal.pone.0058474] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 02/05/2013] [Indexed: 01/02/2023] Open
Abstract
Deciphering mechanisms shaping bacterial diversity should help to build tools to predict the emergence of infectious diseases. Xanthomonads are plant pathogenic bacteria found worldwide. Xanthomonas axonopodis is a genetically heterogeneous species clustering, into six groups, strains that are collectively pathogenic on a large number of plants. However, each strain displays a narrow host range. We address the question of the nature of the evolutionary processes--geographical and ecological speciation--that shaped this diversity. We assembled a large collection of X. axonopodis strains that were isolated over a long period, over continents, and from various hosts. Based on the sequence analysis of seven housekeeping genes, we found that recombination occurred as frequently as point mutation in the evolutionary history of X. axonopodis. However, the impact of recombination was about three times greater than the impact of mutation on the diversity observed in the whole dataset. We then reconstructed the clonal genealogy of the strains using coalescent and genealogy approaches and we studied the diversification of the pathogen using a model of divergence with migration. The suggested scenario involves a first step of generalist diversification that spanned over the last 25,000 years. A second step of ecology-driven specialization occurred during the past two centuries. Eventually, secondary contacts between host-specialized strains probably occurred as a result of agricultural development and intensification, allowing genetic exchanges of virulence-associated genes. These transfers may have favored the emergence of novel pathotypes. Finally, we argue that the largest ecological entity within X. axonopodis is the pathovar.
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Affiliation(s)
- Nadia Mhedbi-Hajri
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Ahmed Hajri
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Tristan Boureau
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Armelle Darrasse
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Karine Durand
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Chrystelle Brin
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Marion Fischer-Le Saux
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Charles Manceau
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Stéphane Poussier
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | | | - Christophe Lemaire
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
| | - Marie-Agnès Jacques
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, Beaucouzé, France
- Université d’Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR4207 QUASAV, PRES L’UNAM, Angers, France
- AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, Angers, France
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Carrión VJ, Gutiérrez-Barranquero JA, Arrebola E, Bardaji L, Codina JC, de Vicente A, Cazorla FM, Murillo J. The mangotoxin biosynthetic operon (mbo) is specifically distributed within Pseudomonas syringae genomospecies 1 and was acquired only once during evolution. Appl Environ Microbiol 2013; 79:756-67. [PMID: 23144138 PMCID: PMC3568555 DOI: 10.1128/aem.03007-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/07/2012] [Indexed: 11/20/2022] Open
Abstract
Mangotoxin production was first described in Pseudomonas syringae pv. syringae strains. A phenotypic characterization of 94 P. syringae strains was carried out to determine the genetic evolution of the mangotoxin biosynthetic operon (mbo). We designed a PCR primer pair specific for the mbo operon to examine its distribution within the P. syringae complex. These primers amplified a 692-bp DNA fragment from 52 mangotoxin-producing strains and from 7 non-mangotoxin-producing strains that harbor the mbo operon, whereas 35 non-mangotoxin-producing strains did not yield any amplification. This, together with the analysis of draft genomes, allowed the identification of the mbo operon in five pathovars (pathovars aptata, avellanae, japonica, pisi, and syringae), all of which belong to genomospecies 1, suggesting a limited distribution of the mbo genes in the P. syringae complex. Phylogenetic analyses using partial sequences from housekeeping genes differentiated three groups within genomospecies 1. All of the strains containing the mbo operon clustered in groups I and II, whereas those lacking the operon clustered in group III; however, the relative branching order of these three groups is dependent on the genes used to construct the phylogeny. The mbo operon maintains synteny and is inserted in the same genomic location, with high sequence conservation around the insertion point, for all the strains in groups I and II. These data support the idea that the mbo operon was acquired horizontally and only once by the ancestor of groups I and II from genomospecies 1 within the P. syringae complex.
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Affiliation(s)
- Víctor J. Carrión
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - José A. Gutiérrez-Barranquero
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Eva Arrebola
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSMUMA-CSIC), Estación Experimental La Mayora, Algarrobo-Costa, Málaga, Spain
| | - Leire Bardaji
- Laboratorio de Patología Vegetal, ETS Ingenieros Agrónomos, Universidad Pública de Navarra, Pamplona, Spain
| | - Juan C. Codina
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Francisco M. Cazorla
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora (IHSM-UMA-CSIC), Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Jesús Murillo
- Laboratorio de Patología Vegetal, ETS Ingenieros Agrónomos, Universidad Pública de Navarra, Pamplona, Spain
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Chowdhury C, Jagannadham MV. Virulence factors are released in association with outer membrane vesicles of Pseudomonas syringae pv. tomato T1 during normal growth. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:231-9. [PMID: 23043909 DOI: 10.1016/j.bbapap.2012.09.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 09/16/2012] [Accepted: 09/28/2012] [Indexed: 12/21/2022]
Abstract
Outer membrane vesicles (OMVs) are released from Pseudomonas syringae pv. tomato T1 (Pst T1) during their normal growth. These extracellular compartments are comprised of a complete set of biological macromolecules that includes proteins, lipids, lipopolysaccharides, etc. It is evident from proteomics analyses the OMVs of Pst T1 contain membrane- and virulence-associated proteins. In addition, OMVs of this organism are also associated with phytotoxin, coronatine. Therefore, OMVs of Pst T1 must play a significant role during pathogenicity to host plant. However, further studies are required whether these structures can serve as "vehicles" for the transport of virulence factors into the host membrane.
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Affiliation(s)
- Chiranjit Chowdhury
- Centre for Cellular and Molecular Biology, Uppal Road, Tarnaka, Hyderabad-500 007, India
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42
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Caldera EJ, Currie CR. The population structure of antibiotic-producing bacterial symbionts of Apterostigma dentigerum ants: impacts of coevolution and multipartite symbiosis. Am Nat 2012; 180:604-17. [PMID: 23070321 DOI: 10.1086/667886] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fungus-growing ants (Attini) are part of a complex symbiosis with Basidiomycetous fungi, which the ants cultivate for food, Ascomycetous fungal pathogens (Escovopsis), which parasitize cultivars, and Actinobacteria, which produce antibiotic compounds that suppress pathogen growth. Earlier studies that have characterized the association between attine ants and their bacterial symbionts have employed broad phylogenetic approaches, with conclusions ranging from a diffuse coevolved mutualism to no specificity being reported. However, the geographic mosaic theory of coevolution proposes that coevolved interactions likely occur at a level above local populations but within species. Moreover, the scale of population subdivision is likely to impact coevolutionary dynamics. Here, we describe the population structure of bacteria associated with the attine Apterostigma dentigerum across Central America using multilocus sequence typing (MLST) of six housekeeping genes. The majority (90%) of bacteria that were isolated grouped into a single clade within the genus Pseudonocardia. In contrast to studies that have suggested that Pseudonocardia dispersal is high and therefore unconstrained by ant associations, we found highly structured ([Formula: see text]) and dispersal-limited (i.e., significant isolation by distance; [Formula: see text], [Formula: see text]) populations over even a relatively small scale (e.g., within the Panama Canal Zone). Estimates of recombination versus mutation were uncharacteristically low compared with estimates for free-living Actinobacteria (e.g., [Formula: see text] in La Selva, Costa Rica), which suggests that recombination is constrained by association with ant hosts. Furthermore, Pseudonocardia population structure was correlated with that of Escovopsis species ([Formula: see text], [Formula: see text]), supporting the bacteria's role in disease suppression. Overall, the population dynamics of symbiotic Pseudonocardia are more consistent with a specialized mutualistic association than with recently proposed models of low specificity and frequent horizontal acquisition.
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Affiliation(s)
- Eric J Caldera
- Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Phylogenetic analysis and polyphasic characterization of Clavibacter michiganensis strains isolated from tomato seeds reveal that nonpathogenic strains are distinct from C. michiganensis subsp. michiganensis. Appl Environ Microbiol 2012; 78:8388-402. [PMID: 23001675 DOI: 10.1128/aem.02158-12] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Clavibacter comprises one species and five subspecies of plant-pathogenic bacteria, four of which are classified as quarantine organisms due to the high economic threat they pose. Clavibacter michiganensis subsp. michiganensis is one of the most important pathogens of tomato, but the recommended diagnostic tools are not satisfactory due to false-negative and/or -positive results. To provide a robust analysis of the genetic relatedness among a worldwide collection of C. michiganensis subsp. michiganensis strains, relatives (strains from the four other C. michiganensis subspecies), and nonpathogenic Clavibacter-like strains isolated from tomato, we performed multilocus sequence-based analysis and typing (MLSA and MLST) based on six housekeeping genes (atpD, dnaK, gyrB, ppK, recA, and rpoB). We compared this "framework" with phenotypic and genotypic characteristics such as pathogenicity on tomato, reaction to two antisera by immunofluorescence and to five PCR identification tests, and the presence of four genes encoding the main C. michiganensis subsp. michiganensis pathogenicity determinants. We showed that C. michiganensis subsp. michiganensis is monophyletic and is distinct from its closest taxonomic neighbors. The nonpathogenic Clavibacter-like strains were identified as C. michiganensis using 16S rRNA gene sequencing. These strains, while cross-reacting with C. michiganensis subsp. michiganensis identification tools, are phylogenetically distinct from the pathogenic strains but belong to the C. michiganensis clade. C. michiganensis subsp. michiganensis clonal complexes linked strains from highly diverse geographical origins and also strains isolated over long periods of time in the same location. This illustrates the importance of seed transmission in the worldwide dispersion of this pathogen and its survival and adaptation abilities in a new environment once introduced.
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Gironde S, Manceau C. Housekeeping gene sequencing and multilocus variable-number tandem-repeat analysis to identify subpopulations within Pseudomonas syringae pv. maculicola and Pseudomonas syringae pv. tomato that correlate with host specificity. Appl Environ Microbiol 2012; 78:3266-79. [PMID: 22389364 PMCID: PMC3346470 DOI: 10.1128/aem.06655-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 02/15/2012] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas syringae pv. maculicola causes bacterial spot on Brassicaceae worldwide, and for the last 10 years severe outbreaks have been reported in the Loire Valley, France. P. syringae pv. maculicola resembles P. syringae pv. tomato in that it is also pathogenic for tomato and causes the same types of symptoms. We used a collection of 106 strains of P. syringae to characterize the relationships between P. syringae pv. maculicola and related pathovars, paying special attention to P. syringae pv. tomato. Phylogenetic analysis of gyrB and rpoD gene sequences showed that P. syringae pv. maculicola, which causes diseases in Brassicaceae, forms six genetic lineages within genomospecies 3 of P. syringae strains as defined by L. Gardan et al. (Int. J. Syst. Bacteriol. 49[Pt 2]:469-478, 1999), whereas P. syringae pv. tomato forms two distinct genetic lineages. A multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) conducted with eight minisatellite loci confirmed the genetic structure obtained with rpoD and gyrB sequence analyses. These results provide promising tools for fine-scale epidemiological studies on diseases caused by P. syringae pv. maculicola and P. syringae pv. tomato. The two pathovars had distinct host ranges; only P. syringae pv. maculicola strains were pathogenic for Brassicaceae. A subpopulation of P. syringae pv. maculicola strains that are pathogenic for Pto-expressing tomato plants were shown to lack avrPto1 and avrPtoB or to contain a disrupted avrPtoB homolog. Taking phylogenetic and pathological features into account, our data suggest that the DC3000 strain belongs to P. syringae pv. maculicola. This study shows that P. syringae pv. maculicola and P. syringae pv. tomato appear multiclonal, as they did not diverge from a single common ancestral group within the ancestral P. syringae genomospecies 3, and suggests that pathovar specificity within P. syringae may be due to independent genetic events.
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Affiliation(s)
- S Gironde
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences (IRHS), INRA, Agrocampus-Ouest, Université d’Angers, Beaucouzé, France
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Wicker E, Lefeuvre P, de Cambiaire JC, Lemaire C, Poussier S, Prior P. Contrasting recombination patterns and demographic histories of the plant pathogen Ralstonia solanacearum inferred from MLSA. THE ISME JOURNAL 2012; 6:961-74. [PMID: 22094345 PMCID: PMC3329105 DOI: 10.1038/ismej.2011.160] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/27/2011] [Accepted: 09/27/2011] [Indexed: 01/14/2023]
Abstract
We used multilocus sequence analysis (MLSA) on a worldwide collection of the plant pathogenic Ralstonia solanacearum (Betaproteobacteria) to retrace its complex evolutionary history. Using genetic imprints left during R. solanacearum evolution, we were able to delineate distinct evolutionary complex displaying contrasting dynamics. Among the phylotypes already described (I, IIA, IIB, III, IV), eight groups of strains with distinct evolutionary patterns, named clades, were identified. From our recombination analysis, we identified 21 recombination events that occurred within and across these lineages. Although appearing the most divergent and ancestral phylotype, phylotype IV was inferred as a gene donor for the majority of the recombination events that we detected. Whereas this phylotype apparently fuelled the species diversity, ongoing diversification was mainly detected within phylotype I, IIA and III. These three groups presented a recent expanding population structure, a high level of homologous recombination and evidences of long-distance migrations. Factors such as adaptation to a specific host or intense trading of infected crops may have promoted this diversification. Whether R. solanacearum lineages will eventually evolve in distinct species remains an open question. The intensification of cropping and increase of geographical dispersion may favour situations of phylotype sympatry and promote higher exchange of key factors for host adaptation from their common genetic pool.
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Affiliation(s)
- Emmanuel Wicker
- CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical CIRAD-Université de la Réunion, Pôle de Protection des Plantes, Saint Pierre, La Réunion, France.
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Pseudomonas syringae type III effector repertoires: last words in endless arguments. Trends Microbiol 2012; 20:199-208. [PMID: 22341410 DOI: 10.1016/j.tim.2012.01.003] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/20/2011] [Accepted: 01/04/2012] [Indexed: 01/10/2023]
Abstract
Many plant pathogens subvert host immunity by injecting compositionally diverse but functionally similar repertoires of cytoplasmic effector proteins. The bacterial pathogen Pseudomonas syringae is a model for exploring the functional structure of such repertoires. The pangenome of P. syringae encodes 57 families of effectors injected by the type III secretion system. Distribution of effector genes among phylogenetically diverse strains reveals a small set of core effectors targeting antimicrobial vesicle trafficking and a much larger set of variable effectors targeting kinase-based recognition processes. Complete disassembly of the 28-effector repertoire of a model strain and reassembly of a minimal functional repertoire reveals the importance of simultaneously attacking both processes. These observations, coupled with growing knowledge of effector targets in plants, support a model for coevolving molecular dialogs between effector repertoires and plant immune systems that emphasizes mutually-driven expansion of the components governing recognition.
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Gori A, Cerboneschi M, Tegli S. High-resolution melting analysis as a powerful tool to discriminate and genotype Pseudomonas savastanoi pathovars and strains. PLoS One 2012; 7:e30199. [PMID: 22295075 PMCID: PMC3266268 DOI: 10.1371/journal.pone.0030199] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 12/12/2011] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas savastanoi is a serious pathogen of Olive, Oleander, Ash, and several other Oleaceae. Its epiphytic or endophytic presence in asymptomatic plants is crucial for the spread of Olive and Oleander knot disease, as already ascertained for P. savastanoi pv. savastanoi (Psv) on Olive and for pv. nerii (Psn) on Oleander, while no information is available for pv. fraxini (Psf) on Ash. Nothing is known yet about the distribution on the different host plants and the real host range of these pathovars in nature, although cross-infections were observed following artificial inoculations. A multiplex Real-Time PCR assay was recently developed to simultaneously and quantitatively discriminate in vitro and in planta these P. savastanoi pathovars, for routine culture confirmation and for epidemiological and diagnostical studies. Here an innovative High-Resolution Melting Analysis (HRMA)-based assay was set up to unequivocally discriminate Psv, Psn and Psf, according to several single nucleotide polymorphisms found in their Type Three Secretion System clusters. The genetic distances among 56 P. savastanoi strains belonging to these pathovars were also evaluated, confirming and refining data previously obtained by fAFLP. To our knowledge, this is the first time that HRMA is applied to a bacterial plant pathogen, and one of the few multiplex HRMA-based assays developed so far. This protocol provides a rapid, sensitive, specific tool to differentiate and detect Psv, Psn and Psf strains, also in vivo and against other related bacteria, with lower costs than conventional multiplex Real-Time PCR. Its application is particularly suitable for sanitary certification programs for P. savastanoi, aimed at avoiding the spreading of this phytopathogen through asymptomatic plants.
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Affiliation(s)
- Andrea Gori
- Laboratorio di Patologia Vegetale e Molecolare, Dipartimento di Biotecnologie Agrarie, Università degli Studi di Firenze, Sesto Fiorentino, Firenze, Italy
| | - Matteo Cerboneschi
- Laboratorio di Patologia Vegetale e Molecolare, Dipartimento di Biotecnologie Agrarie, Università degli Studi di Firenze, Sesto Fiorentino, Firenze, Italy
| | - Stefania Tegli
- Laboratorio di Patologia Vegetale e Molecolare, Dipartimento di Biotecnologie Agrarie, Università degli Studi di Firenze, Sesto Fiorentino, Firenze, Italy
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Sohn KH, Saucet SB, Clarke CR, Vinatzer BA, O'Brien HE, Guttman DS, Jones JDG. HopAS1 recognition significantly contributes to Arabidopsis nonhost resistance to Pseudomonas syringae pathogens. THE NEW PHYTOLOGIST 2012; 193:58-66. [PMID: 22053875 DOI: 10.1111/j.1469-8137.2011.03950.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
• Plant immunity is activated by sensing either conserved microbial signatures, called pathogen/microbe-associated molecular patterns (P/MAMPs), or specific effectors secreted by pathogens. However, it is not known why most microbes are nonpathogenic in most plant species. • Nonhost resistance (NHR) consists of multiple layers of innate immunity and protects plants from the vast majority of potentially pathogenic microbes. Effector-triggered immunity (ETI) has been implicated in race-specific disease resistance. However, the role of ETI in NHR is unclear. • Pseudomonas syringae pv. tomato (Pto) T1 is pathogenic in tomato (Solanum lycopersicum) yet nonpathogenic in Arabidopsis. Here, we show that, in addition to the type III secretion system (T3SS)-dependent effector (T3SE) avrRpt2, a second T3SE of Pto T1, hopAS1, triggers ETI in nonhost Arabidopsis. • hopAS1 is broadly present in P. syringae strains, contributes to virulence in tomato, and is quantitatively required for Arabidopsis NHR to Pto T1. Strikingly, all tested P. syringae strains that are pathogenic in Arabidopsis carry truncated hopAS1 variants of forms, demonstrating that HopAS1-triggered immunity plays an important role in Arabidopsis NHR to a broad-range of P. syringae strains.
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Affiliation(s)
- Kee Hoon Sohn
- The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Simon B Saucet
- The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Christopher R Clarke
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Latham Hall, Blacksburg VA 24061, USA
| | - Boris A Vinatzer
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Latham Hall, Blacksburg VA 24061, USA
| | - Heath E O'Brien
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - David S Guttman
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Jonathan D G Jones
- The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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Miniature transposable sequences are frequently mobilized in the bacterial plant pathogen Pseudomonas syringae pv. phaseolicola. PLoS One 2011; 6:e25773. [PMID: 22016774 PMCID: PMC3189936 DOI: 10.1371/journal.pone.0025773] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/09/2011] [Indexed: 01/01/2023] Open
Abstract
Mobile genetic elements are widespread in Pseudomonas syringae, and often associate with virulence genes. Genome reannotation of the model bean pathogen P. syringae pv. phaseolicola 1448A identified seventeen types of insertion sequences and two miniature inverted-repeat transposable elements (MITEs) with a biased distribution, representing 2.8% of the chromosome, 25.8% of the 132-kb virulence plasmid and 2.7% of the 52-kb plasmid. Employing an entrapment vector containing sacB, we estimated that transposition frequency oscillated between 2.6×10−5 and 1.1×10−6, depending on the clone, although it was stable for each clone after consecutive transfers in culture media. Transposition frequency was similar for bacteria grown in rich or minimal media, and from cells recovered from compatible and incompatible plant hosts, indicating that growth conditions do not influence transposition in strain 1448A. Most of the entrapped insertions contained a full-length IS801 element, with the remaining insertions corresponding to sequences smaller than any transposable element identified in strain 1448A, and collectively identified as miniature sequences. From these, fragments of 229, 360 and 679-nt of the right end of IS801 ended in a consensus tetranucleotide and likely resulted from one-ended transposition of IS801. An average 0.7% of the insertions analyzed consisted of IS801 carrying a fragment of variable size from gene PSPPH_0008/PSPPH_0017, showing that IS801 can mobilize DNA in vivo. Retrospective analysis of complete plasmids and genomes of P. syringae suggests, however, that most fragments of IS801 are likely the result of reorganizations rather than one-ended transpositions, and that this element might preferentially contribute to genome flexibility by generating homologous regions of recombination. A further miniature sequence previously found to affect host range specificity and virulence, designated MITEPsy1 (100-nt), represented an average 2.4% of the total number of insertions entrapped in sacB, demonstrating for the first time the mobilization of a MITE in bacteria.
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Cai R, Yan S, Liu H, Leman S, Vinatzer BA. Reconstructing host range evolution of bacterial plant pathogens using Pseudomonas syringae pv. tomato and its close relatives as a model. INFECTION GENETICS AND EVOLUTION 2011; 11:1738-51. [DOI: 10.1016/j.meegid.2011.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 07/07/2011] [Accepted: 07/12/2011] [Indexed: 10/17/2022]
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