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Pena MM, Bhandari R, Bowers RM, Weis K, Newberry E, Wagner N, Pupko T, Jones JB, Woyke T, Vinatzer BA, Jacques MA, Potnis N. Genetic and Functional Diversity Help Explain Pathogenic, Weakly Pathogenic, and Commensal Lifestyles in the Genus Xanthomonas. Genome Biol Evol 2024; 16:evae074. [PMID: 38648506 PMCID: PMC11032200 DOI: 10.1093/gbe/evae074] [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] [Accepted: 03/29/2024] [Indexed: 04/25/2024] Open
Abstract
The genus Xanthomonas has been primarily studied for pathogenic interactions with plants. However, besides host and tissue-specific pathogenic strains, this genus also comprises nonpathogenic strains isolated from a broad range of hosts, sometimes in association with pathogenic strains, and other environments, including rainwater. Based on their incapacity or limited capacity to cause symptoms on the host of isolation, nonpathogenic xanthomonads can be further characterized as commensal and weakly pathogenic. This study aimed to understand the diversity and evolution of nonpathogenic xanthomonads compared to their pathogenic counterparts based on their cooccurrence and phylogenetic relationship and to identify genomic traits that form the basis of a life history framework that groups xanthomonads by ecological strategies. We sequenced genomes of 83 strains spanning the genus phylogeny and identified eight novel species, indicating unexplored diversity. While some nonpathogenic species have experienced a recent loss of a type III secretion system, specifically the hrp2 cluster, we observed an apparent lack of association of the hrp2 cluster with lifestyles of diverse species. We performed association analysis on a large data set of 337 Xanthomonas strains to explain how xanthomonads may have established association with the plants across the continuum of lifestyles from commensals to weak pathogens to pathogens. Presence of distinct transcriptional regulators, distinct nutrient utilization and assimilation genes, transcriptional regulators, and chemotaxis genes may explain lifestyle-specific adaptations of xanthomonads.
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Affiliation(s)
- Michelle M Pena
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
- Present address: Department of Plant Pathology, University of Georgia, Tifton, GA, USA
| | - Rishi Bhandari
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Robert M Bowers
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kylie Weis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Eric Newberry
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel Aviv, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel Aviv, Israel
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Tanja Woyke
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Life and Environmental Sciences, University of California Merced, Merced, CA, USA
| | - Boris A Vinatzer
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Marie-Agnès Jacques
- Institut Agro, INRAE, IRHS, SFR QUASAV, University of Angers, Angers F-49000, France
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
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2
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Ledman KE, Osdaghi E, Curland RD, Liu Z, Dill-Macky R. Epidemiology, Host Resistance, and Genomics of the Small Grain Cereals Pathogen Xanthomonas translucens: New Advances and Future Prospects. PHYTOPATHOLOGY 2023; 113:2037-2047. [PMID: 36996338 DOI: 10.1094/phyto-11-22-0403-sa] [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: 06/19/2023]
Abstract
Bacterial leaf streak (BLS) primarily affects barley and wheat and is mainly caused by the pathogens Xanthomonas translucens pv. translucens and X. translucens pv. undulosa, respectively. BLS is distributed globally and poses a risk to food security and the supply of malting barley. X. translucens pv. cerealis can infect both wheat and barley but is rarely isolated from these hosts in natural infections. These pathogens have undergone a confusing taxonomic history, and the biology has been poorly understood, making it difficult to develop effective control measures. Recent advancements in the ability and accessibility to sequence bacterial genomes have shed light on phylogenetic relationships between strains and identified genes that may play a role in virulence, such as those that encode Type III effectors. In addition, sources of resistance to BLS have been identified in barley and wheat lines, and ongoing efforts are being made to map these genes and evaluate germplasm. Although there are still gaps in BLS research, progress has been made in recent years to further understand epidemiology, diagnostics, pathogen virulence, and host resistance.
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Affiliation(s)
- Kristi E Ledman
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
| | - Ebrahim Osdaghi
- Department of Plant Protection, University of Tehran, Karaj, Iran
| | - Rebecca D Curland
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND, U.S.A
| | - Ruth Dill-Macky
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
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3
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Heiden N, Broders KA, Hutin M, Castro MO, Roman-Reyna V, Toth H, Jacobs JM. Bacterial Leaf Streak Diseases of Plants: Symptom Convergence in Monocot Plants by Distant Pathogenic Xanthomonas Species. PHYTOPATHOLOGY 2023; 113:2048-2055. [PMID: 37996392 DOI: 10.1094/phyto-05-23-0155-ia] [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: 11/25/2023]
Abstract
Bacterial leaf streak (BLS) is a disease of monocot plants caused by Xanthomonas translucens on small grains, X. vasicola on maize and sorghum, and X. oryzae on rice. These three pathogens cause remarkably similar symptomology in their host plants. Despite causing similar symptoms, BLS pathogens are dispersed throughout the larger Xanthomonas phylogeny. Each aforementioned species includes strain groups that do not cause BLS and instead cause vascular disease. In this commentary, we hypothesize that strains of X. translucens, X. vasicola, and X. oryzae convergently evolved to cause BLS due to shared evolutionary pressures. We examined the diversity of secreted effectors, which may be important virulence factors for BLS pathogens and their evolution. We discuss evidence that differences in gene regulation and abilities to manipulate plant hormones may also separate BLS pathogens from other Xanthomonas species or pathovars. BLS is becoming an increasing issue across the three pathosystems. Overall, we hope that a better understanding of conserved mechanisms used by BLS pathogens will enable researchers to translate findings across production systems and guide approaches to control this (re)emerging threat.
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Affiliation(s)
- Nathaniel Heiden
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Kirk A Broders
- U.S. Department of Agriculture-Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL 61604, U.S.A
| | - Mathilde Hutin
- Plant Health Institute of Montpellier, University of Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Mary Ortiz Castro
- Horticulture and Extension Programs, Colorado State University, Castle Rock, CO 80106, U.S.A
| | - Verónica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Hannah Toth
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, U.S.A
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4
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Shah SMA, Khojasteh M, Wang Q, Haq F, Xu X, Li Y, Zou L, Osdaghi E, Chen G. Comparative Transcriptomic Analysis of Wheat Cultivars in Response to Xanthomonas translucens pv. cerealis and Its T2SS, T3SS, and TALEs Deficient Strains. PHYTOPATHOLOGY 2023; 113:2073-2082. [PMID: 37414408 DOI: 10.1094/phyto-02-23-0049-sa] [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: 07/08/2023]
Abstract
Xanthomonas translucens pv. cerealis causes bacterial leaf streak disease on small grain cereals. Type II and III secretion systems (T2SS and T3SS) play a pivotal role in the pathogenicity of the bacterium, while no data are available on the transcriptomic profile of wheat cultivars infected with either wild type (WT) or mutants of the pathogen. In this study, WT, TAL-effector mutants, and T2SS/T3SS mutants of X. translucens pv. cerealis strain NXtc01 were evaluated for their effect on the transcriptomic profile of two wheat cultivars, 'Chinese Spring' and 'Yangmai-158', using Illumina RNA-sequencing technology. RNA-Seq data showed that the number of differentially expressed genes (DEGs) was higher in Yangmai-158 than in Chinese Spring, suggesting higher susceptibility of Yangmai-158 to the pathogen. In T2SS, most suppressed DEGs were related to transferase, synthase, oxidase, WRKY, and bHLH transcription factors. The gspD mutants showed significantly decreased disease development in wheat, suggesting an active contribution of T2SS in virulence. Moreover, the gspD mutant restored full virulence and its multiplication in planta by addition of gspD in trans. In the T3SS-deficient strain, downregulated DEGs were associated with cytochrome, peroxidases, kinases, phosphatases, WRKY, and ethylene-responsive transcription factors. In contrast, upregulated DEGs were trypsin inhibitors, cell number regulators, and calcium transporter. Transcriptomic analyses coupled with quantitative real-time-PCR indicated that some genes are upregulated in Δtal1/Δtal2 compared with the tal-free strain, but no direct interaction was observed. These results provide novel insight into wheat transcriptomes in response to X. translucens infection and pave the way for understanding host-pathogen interactions.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Moein Khojasteh
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qi Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ying Li
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ebrahim Osdaghi
- Department of Plant Protection, University of Tehran, Karaj, Iran
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture and Biology/Key Laboratory of Urban Agriculture by Ministry of Agriculture of China, Shanghai Jiao Tong University, Shanghai 200240, China
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5
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Liu Z, Friskop A, Jacobs JM, Dill-Macky R. Bacterial Leaf Streak: A Persistent and Increasingly Important Disease Problem for Cereal Crops. PHYTOPATHOLOGY 2023; 113:2020-2023. [PMID: 38015599 DOI: 10.1094/phyto-11-23-0423-sa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Affiliation(s)
- Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND, 58108
| | - Andrew Friskop
- Department of Plant Pathology, North Dakota State University, Fargo, ND, 58108
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210
- Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210
| | - Ruth Dill-Macky
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
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6
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Goettelmann F, Roman-Reyna V, Cunnac S, Jacobs JM, Bragard C, Studer B, Koebnik R, Kölliker R. Complete Genome Assemblies of All Xanthomonas translucens Pathotype Strains Reveal Three Genetically Distinct Clades. Front Microbiol 2022; 12:817815. [PMID: 35310401 PMCID: PMC8924669 DOI: 10.3389/fmicb.2021.817815] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 12/29/2021] [Indexed: 11/13/2022] Open
Abstract
The Xanthomonas translucens species comprises phytopathogenic bacteria that can cause serious damage to cereals and to forage grasses. So far, the genomic resources for X. translucens were limited, which hindered further understanding of the host–pathogen interactions at the molecular level and the development of disease-resistant cultivars. To this end, we complemented the available complete genome sequence of the X. translucens pv. translucens pathotype strain DSM 18974 by sequencing the genomes of all the other 10 X. translucens pathotype strains using PacBio long-read technology and assembled complete genome sequences. Phylogeny based on average nucleotide identity (ANI) revealed three distinct clades within the species, which we propose to classify as clades Xt-I, Xt-II, and Xt-III. In addition to 2,181 core X. translucens genes, a total of 190, 588, and 168 genes were found to be exclusive to each clade, respectively. Moreover, 29 non-transcription activator-like effector (TALE) and 21 TALE type III effector classes were found, and clade- or strain-specific effectors were identified. Further investigation of these genes could help to identify genes that are critically involved in pathogenicity and/or host adaptation, setting the grounds for the development of new resistant cultivars.
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Affiliation(s)
- Florian Goettelmann
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
| | - Veronica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States.,Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
| | - Sébastien Cunnac
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States.,Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
| | - Claude Bragard
- Earth and Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
| | - Bruno Studer
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
| | - Ralf Koebnik
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Roland Kölliker
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
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7
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Shah SMA, Khojasteh M, Wang Q, Taghavi SM, Xu Z, Khodaygan P, Zou L, Mohammadikhah S, Chen G, Osdaghi E. Genomics-Enabled Novel Insight Into the Pathovar-Specific Population Structure of the Bacterial Leaf Streak Pathogen Xanthomonas translucens in Small Grain Cereals. Front Microbiol 2021; 12:674952. [PMID: 34122388 PMCID: PMC8195340 DOI: 10.3389/fmicb.2021.674952] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/27/2021] [Indexed: 11/30/2022] Open
Abstract
The Gram-negative bacterium Xanthomonas translucens infects a wide range of gramineous plants with a notable impact on small grain cereals. However, genomics-informed intra-species population structure and virulence repertories of the pathogen have rarely been investigated. In this study, the complete genome sequences of seven X. translucens strains representing an entire set of genetic diversity of two pathovars X. translucens pv. undulosa and X. translucens pv. translucens is provided and compared with those of seven publicly available complete genomes of the pathogen. Organization of the 25 type III secretion system genes in all the 14 X. translucens strains was exactly the same, while TAL effector genes localized singly or in clusters across four loci in X. translucens pv. translucens and five to six loci in X. translucens pv. undulosa. Beside two previously unreported endogenous plasmids in X. translucens pv. undulosa, and variations in repeat variable diresidue (RVD) of the 14 strains, tal1a of X. translucens pv. translucens strain XtKm8 encode the new RVDs HE and YI which have not previously been reported in xanthomonads. Further, a number of truncated tal genes were predicted among the 14 genomes lacking conserved BamHI site at N-terminus and SphI site at C-terminus. Our data have doubled the number of complete genomes of X. translucens clarifying the population structure and genomics of the pathogen to pave the way in the small grain cereals industry for disease resistance breeding in the 21st century's agriculture.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Moein Khojasteh
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
- Department of Plant Protection, University of Tehran, Karaj, Iran
| | - Qi Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - S. Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Pejman Khodaygan
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Sedighe Mohammadikhah
- Department of Plant Protection, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Ebrahim Osdaghi
- Department of Plant Protection, University of Tehran, Karaj, Iran
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8
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Koebnik R, Burokiene D, Bragard C, Chang C, Saux MFL, Kölliker R, Lang JM, Leach JE, Luna EK, Portier P, Sagia A, Ziegle J, Cohen SP, Jacobs JM. The Complete Genome Sequence of Xanthomonas theicola, the Causal Agent of Canker on Tea Plants, Reveals Novel Secretion Systems in Clade-1 Xanthomonads. PHYTOPATHOLOGY 2021; 111:611-616. [PMID: 32997607 DOI: 10.1094/phyto-07-20-0273-sc] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Xanthomonas theicola is the causal agent of bacterial canker on tea plants. There is no complete genome sequence available for X. theicola, a close relative of the species X. translucens and X. hyacinthi, thus limiting basic research for this group of pathogens. Here, we release a high-quality complete genome sequence for the X. theicola type strain, CFBP 4691T. Single-molecule real-time sequencing with a mean coverage of 264× revealed two contigs of 4,744,641 bp (chromosome) and 40,955 bp (plasmid) in size. Genome mining revealed the presence of nonribosomal peptide synthases, two CRISPR systems, the Xps type 2 secretion system, and the Hrp type 3 secretion system. Surprisingly, this strain encodes an additional type 2 secretion system and a novel type 3 secretion system with enigmatic function, hitherto undescribed for xanthomonads. Four type 3 effector genes were found on complete or partial transposons, suggesting a role of transposons in effector gene evolution and spread. This genome sequence fills an important gap to better understand the biology and evolution of the early-branching xanthomonads, also known as clade-1 xanthomonads.
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Affiliation(s)
- Ralf Koebnik
- IRD, Cirad, Université Montpellier, IPME, Montpellier, France
| | - Daiva Burokiene
- Nature Research Centre, Institute of Botany, Laboratory of Plant Pathology, Akademijos g. 2, Vilnius, Lithuania
| | - Claude Bragard
- Earth & Life Institute, Université Catholique Louvain-la-Neuve, Louvain-la-Neuve, Belgium
| | | | - Marion Fischer-Le Saux
- IRHS-UMR 1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, CIRM-CFBP, Beaucouzé, France
| | - Roland Kölliker
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Universitätstrasse 2, 8092 Zürich, Switzerland
| | - Jillian M Lang
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, U.S.A
| | - Jan E Leach
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, U.S.A
| | - Emily K Luna
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523, U.S.A
| | - Perrine Portier
- IRHS-UMR 1345, Université d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, 49071, CIRM-CFBP, Beaucouzé, France
| | - Angeliki Sagia
- IRD, Cirad, Université Montpellier, IPME, Montpellier, France
- Department of Biology, University of Crete, Heraklion, Greece
| | - Janet Ziegle
- Pacific Biosciences, Menlo Park, CA 94025, U.S.A
| | - Stephen P Cohen
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
- Infectious Disease Institute, The Ohio State University, Columbus, OH 43210, U.S.A
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9
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The HrpG/HrpX Regulon of Xanthomonads-An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria. Microorganisms 2021; 9:microorganisms9010187. [PMID: 33467109 PMCID: PMC7831014 DOI: 10.3390/microorganisms9010187] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/05/2022] Open
Abstract
Bacteria of the genus Xanthomonas cause a wide variety of economically important diseases in most crops. The virulence of the majority of Xanthomonas spp. is dependent on secretion and translocation of effectors by the type 3 secretion system (T3SS) that is controlled by two master transcriptional regulators HrpG and HrpX. Since their discovery in the 1990s, the two regulators were the focal point of many studies aiming to decipher the regulatory network that controls pathogenicity in Xanthomonas bacteria. HrpG controls the expression of HrpX, which subsequently controls the expression of T3SS apparatus genes and effectors. The HrpG/HrpX regulon is activated in planta and subjected to tight metabolic and genetic regulation. In this review, we cover the advances made in understanding the regulatory networks that control and are controlled by the HrpG/HrpX regulon and their conservation between different Xanthomonas spp.
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10
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Gluck-Thaler E, Cerutti A, Perez-Quintero AL, Butchacas J, Roman-Reyna V, Madhavan VN, Shantharaj D, Merfa MV, Pesce C, Jauneau A, Vancheva T, Lang JM, Allen C, Verdier V, Gagnevin L, Szurek B, Beckham GT, De La Fuente L, Patel HK, Sonti RV, Bragard C, Leach JE, Noël LD, Slot JC, Koebnik R, Jacobs JM. Repeated gain and loss of a single gene modulates the evolution of vascular plant pathogen lifestyles. SCIENCE ADVANCES 2020; 6:6/46/eabc4516. [PMID: 33188025 PMCID: PMC7673761 DOI: 10.1126/sciadv.abc4516] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/30/2020] [Indexed: 05/21/2023]
Abstract
Vascular plant pathogens travel long distances through host veins, leading to life-threatening, systemic infections. In contrast, nonvascular pathogens remain restricted to infection sites, triggering localized symptom development. The contrasting features of vascular and nonvascular diseases suggest distinct etiologies, but the basis for each remains unclear. Here, we show that the hydrolase CbsA acts as a phenotypic switch between vascular and nonvascular plant pathogenesis. cbsA was enriched in genomes of vascular phytopathogenic bacteria in the family Xanthomonadaceae and absent in most nonvascular species. CbsA expression allowed nonvascular Xanthomonas to cause vascular blight, while cbsA mutagenesis resulted in reduction of vascular or enhanced nonvascular symptom development. Phylogenetic hypothesis testing further revealed that cbsA was lost in multiple nonvascular lineages and more recently gained by some vascular subgroups, suggesting that vascular pathogenesis is ancestral. Our results overall demonstrate how the gain and loss of single loci can facilitate the evolution of complex ecological traits.
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Affiliation(s)
- Emile Gluck-Thaler
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aude Cerutti
- LIPM, Université de Toulouse, INRAE, CNRS, Université Paul Sabatier, Castanet-Tolosan, France
| | | | - Jules Butchacas
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
- Infectious Disease Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Verónica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
- Infectious Disease Institute, The Ohio State University, Columbus, OH 43210, USA
| | | | - Deepak Shantharaj
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Céline Pesce
- IRD, CIRAD, Université Montpellier, IPME, Montpellier, France
- Earth & Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- HM Clause (Limagrain group), Davis, CA, 95618, USA
| | - Alain Jauneau
- Institut Fédératif de Recherche 3450, Plateforme Imagerie, Pôle de Biotechnologie Végétale, Castanet-Tolosan, France
| | - Taca Vancheva
- IRD, CIRAD, Université Montpellier, IPME, Montpellier, France
- Earth & Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Jillian M Lang
- Agricultural Biology, Colorado State University, Fort Collins, CO, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Valerie Verdier
- IRD, CIRAD, Université Montpellier, IPME, Montpellier, France
| | - Lionel Gagnevin
- IRD, CIRAD, Université Montpellier, IPME, Montpellier, France
| | - Boris Szurek
- IRD, CIRAD, Université Montpellier, IPME, Montpellier, France
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | | | - Ramesh V Sonti
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, India
| | - Claude Bragard
- Earth & Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Jan E Leach
- Agricultural Biology, Colorado State University, Fort Collins, CO, USA
| | - Laurent D Noël
- LIPM, Université de Toulouse, INRAE, CNRS, Université Paul Sabatier, Castanet-Tolosan, France
| | - Jason C Slot
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
- Infectious Disease Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Ralf Koebnik
- IRD, CIRAD, Université Montpellier, IPME, Montpellier, France.
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA.
- Infectious Disease Institute, The Ohio State University, Columbus, OH 43210, USA
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11
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Li T, Mann R, Sawbridge T, Kaur J, Auer D, Spangenberg G. Novel Xanthomonas Species From the Perennial Ryegrass Seed Microbiome - Assessing the Bioprotection Activity of Non-pathogenic Relatives of Pathogens. Front Microbiol 2020; 11:1991. [PMID: 32983016 PMCID: PMC7479056 DOI: 10.3389/fmicb.2020.01991] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/28/2020] [Indexed: 11/13/2022] Open
Abstract
The productivity of the Australian dairy industry is underpinned by pasture grasses, and importantly perennial ryegrass. The performance of these pasture grasses is supported by the fungal endophyte Epichloë spp. that has bioprotection activities, however, the broader microbiome is not well characterized. In this study, we characterized a novel bioprotectant Xanthomonas species isolated from perennial ryegrass (Lolium perenne L. cv. Alto). In vitro and in planta bioassays against key fungal pathogens of grasses (Sclerotium rolfsii, Drechslera brizae and Microdochium nivale) indicated strong bioprotection activities. A complete circular chromosome of ∼5.2 Mb was generated for three strains of the novel Xanthomonas sp. Based on the 16S ribosomal RNA gene, the strains were closely related to the plant pathogen Xanthomonas translucens, however, comparative genomics of 22 closely related xanthomonad strains indicated that these strains were a novel species. The comparative genomics analysis also identified two unique gene clusters associated with the production of bioprotectant secondary metabolites including one associated with a novel nonribosomal peptide synthetase and another with a siderophore. The analysis also identified genes associated with an endophytic lifestyle (e.g., Type VI secretion system), while no genes associated with pathogenicity were identified (e.g., Type III secretion system and effectors). Overall, these results indicate that these strains represent a novel, bioactive, non-pathogenic species of the genus Xanthomonas. Strain GW was the designated type strain of this novel Xanthomonas sp.
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Affiliation(s)
- Tongda Li
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia.,DairyBio, Bundoora, VIC, Australia.,School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia
| | - Ross Mann
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia.,DairyBio, Bundoora, VIC, Australia
| | - Timothy Sawbridge
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia.,DairyBio, Bundoora, VIC, Australia.,School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia
| | - Jatinder Kaur
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia.,DairyBio, Bundoora, VIC, Australia
| | - Desmond Auer
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia
| | - German Spangenberg
- Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia.,DairyBio, Bundoora, VIC, Australia.,School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia
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12
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Teulet A, Gully D, Rouy Z, Camuel A, Koebnik R, Giraud E, Lassalle F. Phylogenetic distribution and evolutionary dynamics of nod and T3SS genes in the genus Bradyrhizobium. Microb Genom 2020; 6:mgen000407. [PMID: 32783800 PMCID: PMC7643967 DOI: 10.1099/mgen.0.000407] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/26/2020] [Indexed: 01/22/2023] Open
Abstract
Bradyrhizobium are abundant soil bacteria and the major symbiont of legumes. The recent availability of Bradyrhizobium genome sequences provides a large source of information for analysis of symbiotic traits. In this study, we investigated the evolutionary dynamics of the nodulation genes (nod) and their relationship with the genes encoding type III secretion systems (T3SS) and their effectors among bradyrhizobia. Based on the comparative analysis of 146 Bradyrhizobium genome sequences, we identified six different types of T3SS gene clusters. The two predominant cluster types are designated RhcIa and RhcIb and both belong to the RhcI-T3SS family previously described in other rhizobia. They are found in 92/146 strains, most of them also containing nod genes. RhcIa and RhcIb gene clusters differ in the genes they carry: while the translocon-encoding gene nopX is systematically found in strains containing RhcIb, the nopE and nopH genes are specifically conserved in strains containing RhcIa, suggesting that these last two genes might functionally substitute nopX and play a role related to effector translocation. Phylogenetic analysis suggests that bradyrhizobia simultaneously gained nod and RhcI-T3SS gene clusters via horizontal transfer or subsequent vertical inheritance of a symbiotic island containing both. Sequence similarity searches for known Nop effector proteins in bradyrhizobial proteomes revealed the absence of a so-called core effectome, i.e. that no effector is conserved among all Bradyrhizobium strains. However, NopM and SUMO proteases were found to be the main effector families, being represented in the majority of the genus. This study indicates that bradyrhizobial T3SSs might play a more significant symbiotic role than previously thought and provides new candidates among T3SS structural proteins and effectors for future functional investigations.
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Affiliation(s)
- Albin Teulet
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/Université de Montpellier/CIRAD, TA-A82/J – Campus de Baillarguet 34398, Montpellier cedex 5, France
| | - Djamel Gully
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/Université de Montpellier/CIRAD, TA-A82/J – Campus de Baillarguet 34398, Montpellier cedex 5, France
| | - Zoe Rouy
- LABGeM, Génomique Métabolique, CEA, Genoscope, Institut François Jacob, Université d’Évry, Université Paris-Saclay, CNRS, Evry, France
| | - Alicia Camuel
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/Université de Montpellier/CIRAD, TA-A82/J – Campus de Baillarguet 34398, Montpellier cedex 5, France
| | - Ralf Koebnik
- IRD, CIRAD, Université de Montpellier, IPME, Montpellier, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/Université de Montpellier/CIRAD, TA-A82/J – Campus de Baillarguet 34398, Montpellier cedex 5, France
| | - Florent Lassalle
- Department of Infectious Disease Epidemiology. Imperial College London, St Mary’s Hospital Campus, Praed Street, London W2 1NY, UK
- Pathogen and Microbes Program, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
- Present address: Pathogen and Microbes Program, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
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13
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Sapkota S, Mergoum M, Liu Z. The translucens group of Xanthomonas translucens: Complicated and important pathogens causing bacterial leaf streak on cereals. MOLECULAR PLANT PATHOLOGY 2020; 21:291-302. [PMID: 31967397 PMCID: PMC7036361 DOI: 10.1111/mpp.12909] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/14/2019] [Accepted: 12/21/2019] [Indexed: 05/31/2023]
Abstract
UNLABELLED Xanthomonas translucens is a group of gram-negative bacteria that can cause important diseases in cereal crops and forage grasses. Different pathovars have been defined according to their host ranges, and molecular and biochemical characteristics. Pathovars have been placed into two major groups: translucens and graminis. The translucens group contains the pathovars causing bacterial leaf streak (BLS) on cereal crops such as wheat, barley, triticale, rye, and oat. In recent years, BLS has re-emerged as a major problem for many wheat- and barley-producing areas worldwide. The biology of the pathogens and the host-pathogen interactions in cereal BLS diseases were poorly understood. However, recent genome sequence data have provided an insight into the bacterial phylogeny and identification and pathogenicity/virulence. Furthermore, identification of sources of resistance to BLS and mapping of the resistance genes have been initiated. TAXONOMY Kingdom Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; Species X. translucens; translucens group pathovars: undulosa, translucens, cerealis, hordei, and secalis; graminis group pathovars: arrhenatheri, graminis, poae, phlei; newly established pathovar: pistaciae. HOST RANGE X. translucens mainly infects plant species in the Poaceae with the translucens group on cereal crop species and the graminis group on forage grass species. However, some strains have been isolated from, and are able to infect, ornamental asparagus and pistachio trees. Most pathovars have a narrow host range, while a few can infect a broad range of hosts. GENOME The complete genome sequence is available for two X. translucens pv. undulosa strains and one pv. translucens strain. A draft genome sequence is also available for at least one strain from each pathovar. The X. translucens pv. undulosa strain Xt4699 was the first to have its complete genome sequenced, which consists of 4,561,137 bp with total GC content approximately at 68% and 3,528 predicted genes. VIRULENCE MECHANISMS Like most xanthomonads, X. translucens utilizes a type III secretion system (T3SS) to deliver a suite of T3SS effectors (T3Es) inside plant cells. Transcription activator-like effectors, a special group of T3Es, have been identified in most of the X. translucens genomes, some of which have been implicated in virulence. Genetic factors determining host range virulence have also been identified.
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Affiliation(s)
- Suraj Sapkota
- Institute of Plant Breeding, Genetics, and GenomicsUniversity of GeorgiaGriffin Campus, GriffinGAUSA
| | - Mohamed Mergoum
- Institute of Plant Breeding, Genetics, and GenomicsUniversity of GeorgiaGriffin Campus, GriffinGAUSA
- Department of Crop and Soil SciencesUniversity of GeorgiaGriffin Campus, GriffinGAUSA
| | - Zhaohui Liu
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
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14
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Curland RD, Gao L, Hirsch CD, Ishimaru CA. Localized Genetic and Phenotypic Diversity of Xanthomonas translucens Associated With Bacterial Leaf Streak on Wheat and Barley in Minnesota. PHYTOPATHOLOGY 2020; 110:257-266. [PMID: 31448998 DOI: 10.1094/phyto-04-19-0134-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bacterial leaf streak (BLS) of wheat and barley has been a disease of increasing concern in the Upper Midwest over the past decade. In this study, intra- and interfield genetic and pathogenic diversity of bacteria causing BLS in Minnesota was evaluated. In 2015, 89 strains were isolated from 100 leaf samples collected from two wheat and two barley fields naturally infected with BLS. Virulence assays and multilocus sequence alignments of four housekeeping genes supported pathovar identifications. All wheat strains were pathogenic on wheat and barley and belonged to the same lineage as the Xanthomonas translucens pv. undulosa-type strain. All barley strains were pathogenic on barley but not on wheat. Three lineages of barley strains were detected. The frequency and number of sequence types of each pathovar varied within and between fields. A significant population variance was detected between populations of X. translucens pv. undulosa collected from different wheat fields. Population stratification of X. translucens pv. translucens was not detected. Significant differences in virulence were detected among three dominant sequence types of X. translucens pv. undulosa but not those of X. translucens pv. translucens. Field trials with wheat and barley plants inoculated with strains of known sequence type and virulence did not detect significant race structures within either pathovar. Knowledge of virulence, sequence types, and population structures of X. translucens on wheat and barley can support studies on plant-bacterial interactions and breeding for BLS disease resistance.
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Affiliation(s)
- Rebecca D Curland
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
| | - Liangliang Gao
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506
| | - Cory D Hirsch
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
| | - Carol A Ishimaru
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
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15
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Roman-Reyna V, Luna EK, Pesce C, Vancheva T, Chang C, Ziegle J, Bragard C, Koebnik R, Lang JM, Leach JE, Jacobs JM. Genome Resource of Barley Bacterial Blight and Leaf Streak Pathogen Xanthomonas translucens pv. translucens strain UPB886. PLANT DISEASE 2020; 104:13-15. [PMID: 31660797 DOI: 10.1094/pdis-05-19-1103-a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Xanthomonas translucens pv. translucens causes bacterial leaf streak and bacterial blight diseases of barley. This pathogen limits barley production globally but remains understudied, with limited genomic resources. To better understand the biology of this X. translucens subgroup, we sequenced the complete genome of the X. translucens pv. translucens strain UPB886.
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Affiliation(s)
- Verónica Roman-Reyna
- Department of Plant Pathology, The Ohio State University, Columbus, OH, U.S.A
- Infectious Disease Institute, The Ohio State University, Columbus, OH, U.S.A
| | - Emily K Luna
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, U.S.A
| | - Céline Pesce
- IRD, Cirad, Université de Montpellier, IPME, Montpellier, France
- Earth & Life Institute, Université Catholique Louvain-la-Neuve, Louvain-la-Neuve, Belgium
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, U.S.A
| | - Taca Vancheva
- IRD, Cirad, Université de Montpellier, IPME, Montpellier, France
- Earth & Life Institute, Université Catholique Louvain-la-Neuve, Louvain-la-Neuve, Belgium
| | | | | | - Claude Bragard
- Earth & Life Institute, Université Catholique Louvain-la-Neuve, Louvain-la-Neuve, Belgium
| | - Ralf Koebnik
- IRD, Cirad, Université de Montpellier, IPME, Montpellier, France
| | - Jillian M Lang
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, U.S.A
| | - Jan E Leach
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, U.S.A
| | - Jonathan M Jacobs
- Department of Plant Pathology, The Ohio State University, Columbus, OH, U.S.A
- Infectious Disease Institute, The Ohio State University, Columbus, OH, U.S.A
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16
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Shah SMA, Haq F, Ma W, Xu X, Wang S, Xu Z, Zou L, Zhu B, Chen G. Tal1 NXtc01 in Xanthomonas translucens pv. cerealis Contributes to Virulence in Bacterial Leaf Streak of Wheat. Front Microbiol 2019; 10:2040. [PMID: 31551976 PMCID: PMC6737349 DOI: 10.3389/fmicb.2019.02040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/19/2019] [Indexed: 12/21/2022] Open
Abstract
Xanthomonas translucens pv. cerealis (Xtc) causes bacterial leaf streak (BLS) of important cereal crops, including wheat (Triticum aestivum) and barley (Hordeum vulgare). Transcription activator-like effectors (TALEs) play vital roles in many plant diseases caused by Xanthomonas spp., however, TALEs have not been previously characterized in Xtc. In this study, the whole genome of NXtc01, a virulent strain of Xtc from Xinjiang, China, was sequenced and compared with genomes of other Xanthomonas spp. Xtc NXtc01 consists of a single 4,622,298 bp chromosome that encodes 4,004 genes. Alignment of the NXtc01 sequence with the draft genome of Xtc strain CFBP 2541 (United States) revealed a single giant inversion and differences in the location of two tal genes, which were designated tal1 and tal2. In NXtc01, both tal genes are located on the chromosome, whereas tal2 is plasmid-encoded in CFBP 2541. The repeat variable diresidues (RVDs) at the 12th and 13th sites within Tal2 repeat units were identical in both strains, whereas Tal1 showed differences in the third RVD. Xtc NXtc01 and CFBP 2541 encoded 35 and 33 non-TALE type III effectors (T3Es), respectively. tal1, tal2, and tal-free deletion mutants of Xtc NXtc01 were constructed and evaluated for virulence. The tal1 and tal-free deletion mutants were impaired with respect to symptom development and growth in wheat, suggesting that tal1 is a virulence factor in NXtc01. This was confirmed in gain-of-function experiments that showed the introduction of tal1, but not tal2, restored virulence to the tal-free mutant. Furthermore, we generated a hrcC deletion mutant of NXtc01; the hrcC mutant was non-pathogenic on wheat and unable to elicit a hypersensitive response in the non-host Nicotiana benthamiana. Our data provide a platform for exploring the roles of both TALEs and non-TALEs in promoting BLS on wheat.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Sai Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Zhu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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17
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Roach R, Mann R, Gambley CG, Chapman T, Shivas RG, Rodoni B. Genomic sequence analysis reveals diversity of Australian Xanthomonas species associated with bacterial leaf spot of tomato, capsicum and chilli. BMC Genomics 2019; 20:310. [PMID: 31014247 PMCID: PMC6480910 DOI: 10.1186/s12864-019-5600-x] [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: 05/09/2018] [Accepted: 03/12/2019] [Indexed: 01/03/2023] Open
Abstract
Background The genetic diversity in Australian populations of Xanthomonas species associated with bacterial leaf spot in tomato, capsicum and chilli were compared to worldwide bacterial populations. The aim of this study was to confirm the identities of these Australian Xanthomonas species and classify them in comparison to overseas isolates. Analysis of whole genome sequence allows for the investigation of bacterial population structure, pathogenicity and gene exchange, resulting in better management strategies and biosecurity. Results Phylogenetic analysis of the core genome alignments and SNP data grouped strains in distinct clades. Patterns observed in average nucleotide identity, pan genome structure, effector and carbohydrate active enzyme profiles reflected the whole genome phylogeny and highlight taxonomic issues in X. perforans and X. euvesicatoria. Circular sequences with similarity to previously characterised plasmids were identified, and plasmids of similar sizes were isolated. Potential false positive and false negative plasmid assemblies were discussed. Effector patterns that may influence virulence on host plant species were analysed in pathogenic and non-pathogenic xanthomonads. Conclusions The phylogeny presented here confirmed X. vesicatoria, X. arboricola, X. euvesicatoria and X. perforans and a clade of an uncharacterised Xanthomonas species shown to be genetically distinct from all other strains of this study. The taxonomic status of X. perforans and X. euvesicatoria as one species is discussed in relation to whole genome phylogeny and phenotypic traits. The patterns evident in enzyme and plasmid profiles indicate worldwide exchange of genetic material with the potential to introduce new virulence elements into local bacterial populations. Electronic supplementary material The online version of this article (10.1186/s12864-019-5600-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- R Roach
- Department of Agriculture and Fisheries, Ecosciences Precinct, Brisbane, QLD, Australia. .,Agriculture Victoria Research Division, Department of Economic Development, Jobs, Transport & Resources, AgriBio, La Trobe University, Bundoora, Victoria, 3083, Australia.
| | - R Mann
- Agriculture Victoria Research Division, Department of Economic Development, Jobs, Transport & Resources, AgriBio, La Trobe University, Bundoora, Victoria, 3083, Australia
| | - C G Gambley
- Department of Agriculture and Fisheries, Applethorpe Research Facility, Applethorpe, QLD, Australia
| | - T Chapman
- Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia
| | - R G Shivas
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, Australia
| | - B Rodoni
- Agriculture Victoria Research Division, Department of Economic Development, Jobs, Transport & Resources, AgriBio, La Trobe University, Bundoora, Victoria, 3083, Australia
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