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Li R, Ren P, Zhang D, Cui P, Zhu G, Xian X, Tang J, Lu G. HpaP divergently regulates the expression of hrp genes in Xanthomonas oryzae pathovars oryzae and oryzicola. MOLECULAR PLANT PATHOLOGY 2023; 24:44-58. [PMID: 36260328 PMCID: PMC9742497 DOI: 10.1111/mpp.13276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
The bacterial pathogens Xanthomonas oryzae pathovars oryzae (Xoo) and oryzicola (Xoc) cause leaf blight and leaf streak diseases on rice, respectively. Pathogenesis is largely defined by the virulence genes harboured in the pathogen genome. Recently, we demonstrated that the protein HpaP of the crucifer pathogen Xanthomonas campestris pv. campestris is an enzyme with both ATPase and phosphatase activities, and is involved in regulating the synthesis of virulence factors and the induction of the hypersensitive response (HR). In this study, we investigated the role of HpaP homologues in Xoo and Xoc. We showed that HpaP is required for full virulence of Xoo and Xoc. Deletion of hpaP in Xoo and Xoc led to a reduction in virulence and alteration in the production of virulence factors, including extracellular polysaccharide and cell motility. Comparative transcriptomics and reverse transcription-quantitative PCR assays revealed that in XVM2 medium, a mimic medium of the plant environment, the expression levels of hrp genes (for HR and pathogenicity) were enhanced in the Xoo hpaP deletion mutant compared to the wild type. By contrast, in the same growth conditions, hrp gene expression was decreased in the Xoc hpaP deletion mutant compared to the wild type. However, an opposite expression pattern was observed when the pathogens grew in planta, where the expression of hrp genes was reduced in the Xoo hpaP mutant but increased in the Xoc hpaP mutant. These findings indicate that HpaP plays a divergent role in Xoo and Xoc, which may lead to the different infection strategies employed by these two pathogens.
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Affiliation(s)
- Rui‐Fang Li
- Plant Protection Research InstituteGuangxi Academy of Agricultural Science, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsNanningGuangxiChina
| | - Pei‐Dong Ren
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Da‐Pei Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Ping Cui
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Gui‐Ning Zhu
- Plant Protection Research InstituteGuangxi Academy of Agricultural Science, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsNanningGuangxiChina
| | - Xiao‐Yong Xian
- Plant Protection Research InstituteGuangxi Academy of Agricultural Science, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsNanningGuangxiChina
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesCollege of Life Science and Technology, Guangxi UniversityNanningChina
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Shao Y, Tang G, Huang Y, Ke W, Wang S, Zheng D, Ruan L. Transcriptional regulator Sar regulates the multiple secretion systems in Xanthomonas oryzae. MOLECULAR PLANT PATHOLOGY 2023; 24:16-27. [PMID: 36177860 PMCID: PMC9742495 DOI: 10.1111/mpp.13272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is a notorious plant pathogen that causes leaf blight of rice cultivars. The pathogenic bacteria possess numerous transcriptional regulators to regulate various biological processes, such as pathogenicity in the host plant. Our previous study identified a new master regulator PXO_RS20790 that is involved in pathogenicity for Xoo against the host rice. However, the molecular functions of PXO_RS20790 are still unclear. Here, we demonstrate that transcriptional regulator Sar (PXO_RS20790) regulates multiple secretion systems. The RNA-sequencing analysis, bacterial one-hybrid assay, and electrophoretic mobility shift assay revealed that Sar enables binding of the promoters of the T1SS-related genes, the avirulence gene, raxX, and positively regulates these genes' expression. Meanwhile, we found that Sar positively regulated the T6SS-1 clusters but did not regulate the T6SS-2 clusters. Furthermore, we revealed that only T6SS-2 is involved in interbacterial competition. We also indicated that Sar could bind the promoters of the T3SS regulators, hrpG and hrpX, to activate these two genes' transcription. Our findings revealed that Sar is a crucial regulator of multiple secretion systems and virulence.
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Affiliation(s)
- Yanan Shao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Guiyu Tang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Yuanyuan Huang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Wenli Ke
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Shasha Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Dehong Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- National Demonstration Center for Experimental Plant Science Education, College of AgricultureGuangxi UniversityNanningChina
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- College of Resources and EnvironmentTibet Agriculture & Animal Husbandry UniversityLinzhiChina
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3
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The MinCDE Cell Division System Participates in the Regulation of Type III Secretion System (T3SS) Genes, Bacterial Virulence, and Motility in Xanthomonas oryzae pv. oryzae. Microorganisms 2022; 10:microorganisms10081549. [PMID: 36013967 PMCID: PMC9414521 DOI: 10.3390/microorganisms10081549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 11/17/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) in rice, which is one of the most severe bacterial diseases in rice in some Asian countries. The type III secretion system (T3SS) of Xoo encoded by the hypersensitive response and pathogenicity (hrp) genes is essential for its pathogenicity in host rice. Here, we identified the Min system (MinC, MinD, and MinE), a negative regulatory system for bacterial cell division encoded by minC, minD, and minE genes, which is involved in negative regulation of hrp genes (hrpB1 and hrpF) in Xoo. We found that the deletion of minC, minD, and minCDE resulted in enhanced hrpB1 and hrpF expression, which is dependent on two key hrp regulators HrpG and HrpX. The minC, minD, and minCDE mutants exhibited elongated cell lengths, and the classic Min system-defective cell morphology including minicells and short filamentations. Mutation of minC in Xoo resulted in significantly impaired virulence in host rice, swimming motility, and enhanced biofilm formation. Our transcriptome profiling also indicated some virulence genes were differentially expressed in the minC mutants. To our knowledge, this is the first report about the Min system participating in the regulation of T3SS expression. It sheds light on the understanding of Xoo virulence mechanisms.
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Cai L, Ma W, Zou L, Xu X, Xu Z, Deng C, Qian W, Chen X, Chen G. Xanthomonas oryzae Pv. oryzicola Response Regulator VemR Is Co-opted by the Sensor Kinase CheA for Phosphorylation of Multiple Pathogenicity-Related Targets. Front Microbiol 2022; 13:928551. [PMID: 35756024 PMCID: PMC9218911 DOI: 10.3389/fmicb.2022.928551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Two-component systems (TCSs) (cognate sensor histidine kinase/response regulator pair, HK/RR) play a crucial role in bacterial adaptation, survival, and productive colonization. An atypical orphan single-domain RR VemR was characterized by the non-vascular pathogen Xanthomonas oryzae pv. oryzicola (Xoc) is known to cause bacterial leaf streak (BLS) disease in rice. Xoc growth and pathogenicity in rice, motility, biosynthesis of extracellular polysaccharide (EPS), and the ability to trigger HR in non-host tobacco were severely compromised in the deletion mutant strain RΔvemR as compared to the wild-type strain RS105. Site-directed mutagenesis and phosphotransfer experiments revealed that the conserved aspartate (D56) residue within the stand-alone phosphoacceptor receiver (REC) domain is essential for phosphorelay and the regulatory activity of Xoc VemR. Yeast two-hybrid (Y2H) and co-immunoprecipitation (co-IP) data identified CheA as the HK co-opting the RR VemR for phosphorylation. Affinity proteomics identified several downstream VemR-interacting proteins, such as 2-oxoglutarate dehydrogenase (OGDH), DNA-binding RR SirA, flagellar basal body P-ring formation protein FlgA, Type 4a pilus retraction ATPase PilT, stress-inducible sensor HK BaeS, septum site-determining protein MinD, cytoskeletal protein CcmA, and Type III and VI secretion system proteins HrpG and Hcp, respectively. Y2H and deletion mutant analyses corroborated that VemR interacted with OGDH, SirA, FlgA, and HrpG; thus, implicating multi-layered control of diverse cellular processes including carbon metabolism, motility, and pathogenicity in the rice. Physical interaction between VemR and HrpG suggested cross-talk interaction between CheA/VemR- and HpaS/HrpG-mediated signal transduction events orchestrating the hrp gene expression.
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Affiliation(s)
- Lulu Cai
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Chaoying Deng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaobin Chen
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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Jibrin MO, Timilsina S, Minsavage GV, Vallad GE, Roberts PD, Goss EM, Jones JB. Bacterial Spot of Tomato and Pepper in Africa: Diversity, Emergence of T5 Race, and Management. Front Microbiol 2022; 13:835647. [PMID: 35509307 PMCID: PMC9058171 DOI: 10.3389/fmicb.2022.835647] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial spot disease was first reported from South Africa by Ethel M. Doidge in 1920. In the ensuing century after the initial discovery, the pathogen has gained global attention in plant pathology research, providing insights into host-pathogen interactions, pathogen evolution, and effector discovery, such as the first discovery of transcription activation-like effectors, among many others. Four distinct genetic groups, including Xanthomonas euvesicatoria (proposed name: X. euvesicatoria pv. euvesicatoria), Xanthomonas perforans (proposed name: X. euvesicatoria pv. perforans), Xanthomonas gardneri (proposed name: Xanthomonas hortorum pv. gardneri), and Xanthomonas vesicatoria, are known to cause bacterial spot disease. Recently, a new race of a bacterial spot pathogen, race T5, which is a product of recombination between at least two Xanthomonas species, was reported in Nigeria. In this review, our focus is on the progress made on the African continent, vis-à-vis progress made in the global bacterial spot research community to provide a body of information useful for researchers in understanding the diversity, evolutionary changes, and management of the disease in Africa.
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Affiliation(s)
- Mustafa Ojonuba Jibrin
- Tree Fruit Research and Extension Center, Washington State University, Wenatchee, WA, United States
- Department of Crop Protection, Ahmadu Bello University, Zaria, Nigeria
| | - Sujan Timilsina
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
| | - Gerald V. Minsavage
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
| | - Garry E. Vallad
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, United States
| | - Pamela D. Roberts
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- UF/IFAS Southwest Florida Research and Education Center, Immokalee, FL, United States
| | - Erica M. Goss
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Jeffrey B. Jones
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
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Ruiz CH, Osorio-Llanes E, Trespalacios MH, Mendoza-Torres E, Rosales W, Gómez CMM. Quorum Sensing Regulation as a Target for Antimicrobial Therapy. Mini Rev Med Chem 2021; 22:848-864. [PMID: 34856897 DOI: 10.2174/1389557521666211202115259] [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: 10/04/2020] [Revised: 05/20/2021] [Accepted: 09/04/2021] [Indexed: 11/22/2022]
Abstract
Some bacterial species use a cell-to-cell communication mechanism called Quorum Sensing (QS). Bacteria release small diffusible molecules, usually termed signals which allow the activation of beneficial phenotypes that guarantee bacterial survival and the expression of a diversity of virulence genes in response to an increase in population density. The study of the molecular mechanisms that relate signal molecules with bacterial pathogenesis is an area of growing interest due to its use as a possible therapeutic alternative through the development of synthetic analogues of autoinducers as a strategy to regulate bacterial communication as well as the study of bacterial resistance phenomena, the study of these relationships is based on the structural diversity of natural or synthetic autoinducers and their ability to inhibit bacterial QS, which can be approached with a molecular perspective from the following topics: i) Molecular signals and their role in QS regulation; ii) Strategies in the modulation of Quorum Sensing; iii) Analysis of Bacterial QS circuit regulation strategies; iv) Structural evolution of natural and synthetic autoinducers as QS regulators. This mini-review allows a molecular view of the QS systems, showing a perspective on the importance of the molecular diversity of autoinducer analogs as a strategy for the design of new antimicrobial agents.
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Affiliation(s)
- Caterine Henríquez Ruiz
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
| | - Estefanie Osorio-Llanes
- Faculty of Exact and Natural sciences. Grupo de Investigación Avanzada en Biomedicina. Universidad Libre. Barranquilla. Colombia
| | - Mayra Hernández Trespalacios
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
| | - Evelyn Mendoza-Torres
- Faculty of Health Sciences. Grupo de Investigación Avanzada en Biomedicina-Universidad Libre. Barranquilla. Colombia
| | - Wendy Rosales
- Faculty of Exact and Natural sciences. Grupo de Investigación Avanzada en Biomedicina. Universidad Libre. Barranquilla. Colombia
| | - Carlos Mario Meléndez Gómez
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
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Kakkar A, Verma RK, Samal B, Chatterjee S. Interplay between the cyclic di-GMP network and the cell-cell signalling components coordinates virulence-associated functions in Xanthomonas oryzae pv. oryzae. Environ Microbiol 2021; 23:5433-5462. [PMID: 34240791 DOI: 10.1111/1462-2920.15664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 07/06/2021] [Indexed: 11/29/2022]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes a serious disease of rice known as bacterial leaf blight. Several virulence-associated functions have been characterized in Xoo. However, the role of important second messenger c-di-GMP signalling in the regulation of virulence-associated functions still remains elusive in this phytopathogen. In this study we have performed an investigation of 13 c-di-GMP modulating deletion mutants to understand their contribution in Xoo virulence and lifestyle transition. We show that four Xoo proteins, Xoo2331, Xoo2563, Xoo2860 and Xoo2616, are involved in fine-tuning the in vivo c-di-GMP abundance and also play a role in the regulation of virulence-associated functions. We have further established the importance of the GGDEF domain of Xoo2563, a previously characterized c-di-GMP phosphodiesterase, in the virulence-associated functions of Xoo. Interestingly the strain harbouring the GGDEF domain deletion (ΔXoo2563GGDEF ) exhibited EPS deficiency and hypersensitivity to streptonigrin, indicative of altered iron metabolism. This is in contrast to the phenotype exhibited by an EAL overexpression strain wherein, the ΔXoo2563GGDEF exhibited other phenotypes, similar to the strain overexpressing the EAL domain. Taken together, our results indicate a complex interplay of c-di-GMP signalling with the cell-cell signalling to coordinate virulence-associated function in Xoo.
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Affiliation(s)
- Akanksha Kakkar
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
| | - Raj Kumar Verma
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
| | - Biswajit Samal
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
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The Xanthomonas RaxH-RaxR Two-Component Regulatory System Is Orthologous to the Zinc-Responsive Pseudomonas ColS-ColR System. Microorganisms 2021; 9:microorganisms9071458. [PMID: 34361895 PMCID: PMC8306577 DOI: 10.3390/microorganisms9071458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 01/08/2023] Open
Abstract
Genome sequence comparisons to infer likely gene functions require accurate ortholog assignments. In Pseudomonas spp., the sensor-regulator ColS-ColR two-component regulatory system responds to zinc and other metals to control certain membrane-related functions, including lipid A remodeling. In Xanthomonas spp., three different two-component regulatory systems, RaxH-RaxR, VgrS-VgrR, and DetS-DetR, have been denoted as ColS-ColR in several different genome annotations and publications. To clarify these assignments, we compared the sensor periplasmic domain sequences and found that those from Pseudomonas ColS and Xanthomonas RaxH share a similar size as well as the location of a Glu-X-X-Glu metal ion-binding motif. Furthermore, we determined that three genes adjacent to raxRH are predicted to encode enzymes that remodel the lipid A component of lipopolysaccharide. The modifications catalyzed by lipid A phosphoethanolamine transferase (EptA) and lipid A 1-phosphatase (LpxE) previously were detected in lipid A from multiple Xanthomonas spp. The third gene encodes a predicted lipid A glycosyl transferase (ArnT). Together, these results indicate that the Xanthomonas RaxH-RaxR system is orthologous to the Pseudomonas ColS-ColR system that regulates lipid A remodeling. To avoid future confusion, we recommend that the terms ColS and ColR no longer be applied to Xanthomonas spp., and that the Vgr, Rax, and Det designations be used instead.
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Zeng Y, Charkowski AO. The Role of ATP-Binding Cassette Transporters in Bacterial Phytopathogenesis. PHYTOPATHOLOGY 2021; 111:600-610. [PMID: 33225831 DOI: 10.1094/phyto-06-20-0212-rvw] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Bacteria use selective membrane transporting strategies to support cell survival in different environments. Of the membrane transport systems, ATP-binding cassette (ABC) transporters, which utilize the energy of ATP hydrolysis to deliver substrate across the cytoplasmic membrane, are the largest and most diverse superfamily. These transporters import nutrients, export molecules, and are required for diverse cell functions, including cell division and morphology, gene regulation, surface motility, chemotaxis, and interspecies competition. Phytobacterial pathogens encode numerous ABC transporter homologs compared with related nonphytopathogens, with up to 160 transporters per genome, suggesting that plant pathogens must be able to import or respond to a greater number of molecules compared with saprophytes or animal pathogens. Despite their importance, ABC transporters have been little examined in plant pathogens. To understand bacterial phytopathogenesis and evolution, we need to understand the roles that ABC transporters play in plant-microbe interactions. In this review, we outline a multitude of roles that bacterial ABC transporters play, using both plant and animal pathogens as examples, to emphasize the importance of exploring these transporters in phytobacteriology.
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Affiliation(s)
- Yuan Zeng
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523
| | - Amy O Charkowski
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523
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10
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Secrete or perish: The role of secretion systems in Xanthomonas biology. Comput Struct Biotechnol J 2020; 19:279-302. [PMID: 33425257 PMCID: PMC7777525 DOI: 10.1016/j.csbj.2020.12.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Xanthomonas genus are mainly phytopathogens of a large variety of crops of economic importance worldwide. Xanthomonas spp. rely on an arsenal of protein effectors, toxins and adhesins to adapt to the environment, compete with other microorganisms and colonize plant hosts, often causing disease. These protein effectors are mainly delivered to their targets by the action of bacterial secretion systems, dedicated multiprotein complexes that translocate proteins to the extracellular environment or directly into eukaryotic and prokaryotic cells. Type I to type VI secretion systems have been identified in Xanthomonas genomes. Recent studies have unravelled the diverse roles played by the distinct types of secretion systems in adaptation and virulence in xanthomonads, unveiling new aspects of their biology. In addition, genome sequence information from a wide range of Xanthomonas species and pathovars have become available recently, uncovering a heterogeneous distribution of the distinct families of secretion systems within the genus. In this review, we describe the architecture and mode of action of bacterial type I to type VI secretion systems and the distribution and functions associated with these important nanoweapons within the Xanthomonas genus.
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Ogunyemi SO, Zhang M, Abdallah Y, Ahmed T, Qiu W, Ali MA, Yan C, Yang Y, Chen J, Li B. The Bio-Synthesis of Three Metal Oxide Nanoparticles (ZnO, MnO 2, and MgO) and Their Antibacterial Activity Against the Bacterial Leaf Blight Pathogen. Front Microbiol 2020; 11:588326. [PMID: 33343527 PMCID: PMC7746657 DOI: 10.3389/fmicb.2020.588326] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/13/2020] [Indexed: 01/09/2023] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the most infectious pathogen of rice, which causes bacterial leaf blight (BLB) disease. However, the accumulation of chemical or antibiotic resistance of Xoo necessitate the development of its alternative control. In this study, we biologically synthesize three metal oxide nanoparticles (ZnO, MnO2, and MgO) using rhizophytic bacteria Paenibacillus polymyxa strain Sx3 as reducing agent. The biosynthesis of nanoparticles was confirmed and characterized by using UV-vis spectroscopy, XRD, FTIR, EDS, SEM, and TEM analysis. The UV Vis reflectance of the nanoparticle had peaks at 385, 230, and 230 nm with an average crystallite particle size 62.8, 18.8, and 10.9 nm for ZnO, MnO2, and MgO, respectively. Biogenic ZnO, MnO2, and MgO nanoparticles showed substantial significant inhibition effects against Xoo strain GZ 0006 at a concentration of 16.0 μg/ml, for which the antagonized area was 17, 13, and 13 mm and the biofilm formation was decreased by 74.5, 74.4, and 80.2%, respectively. Moreover, the underlining mechanism of nanoparticles was inferred to be in relation to the reactive oxygen species based on their antibacterial efficiency and the deformity in the cell wall phenomenon. Overall, an attractive and eco-friendly biogenic ZnO, MnO2, and MgO nanoparticles were successfully produced. Altogether, the results suggest that the nanoparticles had an excellent antibacterial efficacy against BLB disease in rice plants, together with the increase in growth parameter and rice biomass. In conclusion, the synthesized nanoparticles could serve as an alternative safe measure in combatting the antibiotic-resistant of Xoo.
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Affiliation(s)
- Solabomi Olaitan Ogunyemi
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- Department of Crop Protection, Federal University of Agriculture Abeokuta, Abeokuta, Nigeria
| | - Muchen Zhang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yasmine Abdallah
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- Department of Plant Pathology, Faculty of Agriculture, Minia University, Minya, Egypt
| | - Temoor Ahmed
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Wen Qiu
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Md. Arshad Ali
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Chengqi Yan
- Institute of Plant Virology, Ningbo University, Ningbo, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Yong Yang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jianping Chen
- Institute of Plant Virology, Ningbo University, Ningbo, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Bin Li
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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Antar A, Lee MA, Yoo Y, Cho MH, Lee SW. PXO_RS20535, Encoding a Novel Response Regulator, Is Required for Chemotactic Motility, Biofilm Formation, and Tolerance to Oxidative Stress in Xanthomonas oryzae pv. oryzae. Pathogens 2020; 9:pathogens9110956. [PMID: 33212951 PMCID: PMC7698356 DOI: 10.3390/pathogens9110956] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 11/16/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight of rice, possesses two-component regulatory systems (TCSs) as an intracellular signaling pathway. In this study, we observed changes in virulence, biofilm formation, motility, chemotaxis, and tolerance against oxidative stress of a knockout mutant strain for the PXO_RS20535 gene, encoding an orphan response regulator (RR). The mutant strain lost virulence, produced significantly less biofilm, and showed remarkably reduced motility in swimming, swarming, and twitching. Furthermore, the mutant strain lost glucose-guided movement and showed clear diminution of growth and survival in the presence of H2O2. These results indicate that the RR protein encoded in the PXO_RS20535 gene (or a TCS mediated by the protein) is closely involved in regulation of biofilm formation, all types of motility, chemotaxis, and tolerance against reactive oxygen species (ROS) in Xoo. Moreover we found that the expression of most genes required for a type six secretion system (T6SS) was decreased in the mutant, suggesting that lack of the RR gene most likely leads to defect of T6SS in Xoo.
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Affiliation(s)
- Abdulwahab Antar
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin 17104, Korea; (A.A.); (M.-A.L.); (Y.Y.); (M.-H.C.)
- Crop Biotech Institute, Kyung Hee University, Yongin 17104, Korea
| | - Mi-Ae Lee
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin 17104, Korea; (A.A.); (M.-A.L.); (Y.Y.); (M.-H.C.)
- Crop Biotech Institute, Kyung Hee University, Yongin 17104, Korea
| | - Youngchul Yoo
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin 17104, Korea; (A.A.); (M.-A.L.); (Y.Y.); (M.-H.C.)
- Crop Biotech Institute, Kyung Hee University, Yongin 17104, Korea
| | - Man-Ho Cho
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin 17104, Korea; (A.A.); (M.-A.L.); (Y.Y.); (M.-H.C.)
| | - Sang-Won Lee
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin 17104, Korea; (A.A.); (M.-A.L.); (Y.Y.); (M.-H.C.)
- Crop Biotech Institute, Kyung Hee University, Yongin 17104, Korea
- Correspondence:
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Shahbaz MU, Qian S, Yun F, Zhang J, Yu C, Tian F, Yang F, Chen H. Identification of the Regulatory Components Mediated by the Cyclic di-GMP Receptor Filp and Its Interactor PilZX3 and Functioning in Virulence of Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:1196-1208. [PMID: 32720873 DOI: 10.1094/mpmi-04-20-0088-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: 06/11/2023]
Abstract
The degenerate GGDEF/EAL domain protein Filp was previously shown to function as a cyclic di-GMP (c-di-GMP) signal receptor through its specific interaction with an atypical PilZ domain protein PilZX3 (formerly PXO_02715) and that this interaction is involved in regulating virulence in Xanthomonas oryzae pv. oryzae. As a step toward understanding the regulatory role of Filp/PilZX3-mediated c-di-GMP signaling in the virulence of X. oryzae pv. oryzae, differentially expressed proteins (DEPs) downstream of Filp/PilZX3 were identified by isobaric tagging for relative and absolute quantitation (iTRAQ). A total of 2,346 proteins were identified, of which 157 displayed significant differential expression in different strains. Western blot and quantitative reverse transcription-PCR analyses showed that the expression of HrrP (histidine kinase-response regulator hybrid protein), PhrP (PhoPQ-regulated protein), ProP (prophage Lp2 protein 6) were increased in the ∆filp, ∆pilZX3, and ∆filp∆pilZX3 mutant strains, while expression of CheW1 (chemotaxis protein CheW1), EdpX2 (the second EAL domain protein identified in X. oryzae pv. oryzae), HGdpX2 (the second HD-GYP domain protein identified in X. oryzae pv. oryzae) was decreased in all mutant strains compared with that in the wild type, which was consistent with the iTRAQ data. Deletion of the hrrP and proP genes resulted in significant increases in virulence, whereas deletion of the cheW1, hGdpX2, or tdrX2 genes resulted in decreased virulence. Enzyme assays indicated that EdpX2 and HGdpX2 were active phosphodiesterases (PDEs). This study provides a proteomic description of putative regulatory pathway of Filp and PilZX3 and characterized novel factors that contributed to the virulence of X. oryzae pv. oryzae regulated by c-di-GMP signaling.
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Affiliation(s)
- Muhammad Umar Shahbaz
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Plant Pathology Section, Plant Pathology Research Institute, AARI, Faisalabad 38850, Pakistan
| | - Shanshan Qian
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fei Yun
- National Tobacco Cultivation and Physiology and Biochemistry Research Centre/Key Laboratory for Tobacco Cultivation of Tobacco Industry, Henan Agricultural University, Zhengzhou 450002, China
| | - Jie Zhang
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chao Yu
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fang Tian
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fenghuan Yang
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huamin Chen
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Yang P, Li FJ, Huang SW, Luo M, Lin W, Yuan GQ, Li QQ. Physiological and Transcriptional Response of Xanthomonas oryzae pv. oryzae to Berberine, an Emerging Chemical Control. PHYTOPATHOLOGY 2020; 110:1027-1038. [PMID: 31961254 DOI: 10.1094/phyto-09-19-0327-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Berberine, a botanical drug, has great ability to inhibit the growth of Xanthomonas oryzae pv. oryzae. However, the antibacterial mechanism of berberine against X. oryzae pv. oryzae remains poorly understood. In this study, we investigated the physiological and transcriptional response of X. oryzae pv. oryzae to berberine. When strain X. oryzae pv. oryzae GX13 was treated with berberine (10 µg/ml), the hypersensitive response in tobacco, virulence to rice, pathogen population in the rice xylem, production of extracellular polysaccharide (EPS), and activity of extracellular hydrolases decreased, but the levels of pyruvate and ATP increased. Moreover, biofilm formation was inhibited, and the cell membrane was damaged. Transcriptome sequencing analysis showed downregulated expression of gspD, gspE, and gspF, involved in the type II secretion system (T2SS); hrcC, hrcJ, hrcN, and others, involved in the type III secretion system (T3SS); gumB and gumC, associated with EPS; zapE, ftsQ, and zapA, associated with cell division; lpxH, lpxK, kdtA, and others, associated with the membrane; and pyk, pgk, and mdh, encoding pyruvate kinase, phosphoglycerate kinase, and malate dehydrogenase, respectively. Upregulated expression was observed for nuoA, nuoB, and nuoH, encoding the NADH dehydrogenase complex, and atpF, atpC, and atpB, encoding ATP synthase. An adenylate cyclase (CyaA) fusion assay showed that berberine affects type three effector protein secretion via the T3SS and reduces effector translocation in X. oryzae pv. oryzae. It is speculated that the negative growth and virulence phenotypes of berberine-treated X. oryzae pv. oryzae GX13 may involve differentially expressed genes associated with cytoarchitecture and energy metabolism, and these effects on primary cell function may further dampen virulence and result in differential expression of T3SS- and T2SS-related genes.
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Affiliation(s)
- Ping Yang
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
| | - Fang-Jing Li
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
| | - Shi-Wen Huang
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
- Rice Technology R&D Center, China National Rice Research Institute, Hangzhou 310006, People's Republic of China
| | - Man Luo
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
| | - Wei Lin
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
| | - Gao-Qing Yuan
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
| | - Qi-Qin Li
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
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Bansal K, Kumar S, Patil PB. Phylogenomic Insights into Diversity and Evolution of Nonpathogenic Xanthomonas Strains Associated with Citrus. mSphere 2020; 5:e00087-20. [PMID: 32295869 PMCID: PMC7160680 DOI: 10.1128/msphere.00087-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/18/2020] [Indexed: 01/24/2023] Open
Abstract
Xanthomonas species are primarily known as a group of phytopathogens infecting diverse plants. Recent molecular studies reveal the existence of potential novel species and strains of Xanthomonas following a nonpathogenic lifestyle. In the present study, we report whole-genome sequences of four nonpathogenic strains from citrus (NPXc). Taxonogenomics revealed the surprising diversity, as each of these three isolates were found to be potential novel species that together form a citrus-associated nonpathogenic Xanthomonas species complex (NPXc complex). Interestingly, this NPXc complex is related to another nonpathogenic species, Xanthomonas sontii, from rice (NPXr). On the other hand, the fourth NPXc isolate was found to be related to nonpathogenic isolates from walnut (NPXw); altogether, they form a potential taxonomic outlier of pathogenic Xanthomonas arboricola species. Furthermore, genomic investigation of well-characterized pathogenicity clusters in NPXc isolates revealed lifestyle-specific gene content dynamics. Primarily, genes essential for virulence (i.e., type 1 secretion system [T1SS], T2SS and its effectors, T3SS and its effectors, T4SS, T6SS, adhesins, and rpf gene cluster) and adaptation (i.e., gum, iron uptake and utilization, xanthomonadin, and two-component systems) were depicted by comparative genomics of a Xanthomonas community comprising diverse lifestyles. Overall, the present analysis confers that nonpathogenic isolates of diverse hosts phylogenomically converge and are evolving in parallel with their pathogenic counterparts. Hence, there is a need to understand the world of nonpathogenic isolates from diverse and economically important hosts. Genomic knowledge and resources of nonpathogenic strains will be invaluable in both basic and applied research of the genus XanthomonasIMPORTANCEXanthomonas citri is one of the top phytopathogenic bacteria and is the causal agent of citrus canker. Interestingly, Xanthomonas is also reported to be associated with healthy citrus plants. The advent of the genomic era enabled us to carry out a detailed evolutionary study of a Xanthomonas community associated with citrus and other plants. Our genome-based investigations have revealed hidden and extreme interstrain diversity of nonpathogenic Xanthomonas strains from citrus plants, warranting further large-scale studies. This indicates an unexplored world of Xanthomonas from healthy citrus plant species that may be coevolving as a species complex with the host, unlike the variant pathogenic species. The knowledge and genomic resources will be valuable in evolutionary studies exploring its hidden potential and management of pathogenic species.
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Affiliation(s)
- Kanika Bansal
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sanjeet Kumar
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Prabhu B Patil
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
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Sengoda VG, Shi X, Krugner R, Backus EA, Lin H. Targeted Mutations in Xylella fastidiosa Affect Acquisition and Retention by the Glassy-Winged Sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:612-621. [PMID: 31903491 DOI: 10.1093/jee/toz352] [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] [Received: 09/26/2019] [Indexed: 06/10/2023]
Abstract
Xylella fastidiosa (Wells) is a xylem-limited bacterium that causes Pierce's disease of grapevines. The bacterium is transmitted by insect vectors such as the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar). Experiments were conducted to compare the role of selected X. fastidiosa genes on 1) bacterial acquisition and retention in GWSS foreguts, and 2) transmission to grapevines by GWSS. Bacterial genotypes used were: mutants Xf-ΔpilG, Xf-ΔpilH, Xf-ΔgacA, and Xf-ΔpopP; plus wild type (WT) as control. Results showed that Xf-ΔpilG had enhanced colonization rate and larger numbers in GWSS compared with WT. Yet, Xf-ΔpilG exhibited the same transmission efficiency as WT. The Xf-ΔpilH exhibited poor acquisition and retention. Although initial adhesion, multiplication, and retention of Xf-ΔpilH in GWSS were almost eliminated compared with WT, the mutation did not reduce transmission success in grapevines. Overall, Xf-ΔgacA showed colonization rates and numbers in foreguts similar to WT. The Xf-ΔgacA mutation did not affect initial adhesion, multiplication, and long-term retention compared with WT, and was not significantly diminished in transmission efficiency. In contrast, numbers of Xf-ΔpopP were variable over time, displaying greatest fluctuation from highest to lowest levels. Thus, Xf-ΔpopP had a strong, negative effect on initial adhesion, but adhered and slowly multiplied in the foregut. Again, transmission was not diminished compared to WT. Despite reductions in acquisition and retention by GWSS, transmission efficiency of genotypes to grapevines was not affected. Therefore, in order to stop the spread of X. fastidiosa by GWSS using gene-level targets, complete disruption of bacterial colonization mechanisms is required.
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Affiliation(s)
- Venkatesan G Sengoda
- United States Department of Agriculture, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA
| | - Xiangyang Shi
- United States Department of Agriculture, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA
| | - Rodrigo Krugner
- United States Department of Agriculture, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA
| | - Elaine A Backus
- United States Department of Agriculture, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA
| | - Hong Lin
- United States Department of Agriculture, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA
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Wei C, Ding T, Chang C, Yu C, Li X, Liu Q. Global Regulator PhoP is Necessary for Motility, Biofilm Formation, Exoenzyme Production and Virulence of Xanthomonas citri Subsp. citri on Citrus Plants. Genes (Basel) 2019; 10:genes10050340. [PMID: 31064142 PMCID: PMC6562643 DOI: 10.3390/genes10050340] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/28/2019] [Accepted: 05/02/2019] [Indexed: 01/27/2023] Open
Abstract
Citrus canker caused by Xanthomonas citri subsp. citri is one of the most important bacterial diseases of citrus, impacting both plant growth and fruit quality. Identifying and elucidating the roles of genes associated with pathogenesis has aided our understanding of the molecular basis of citrus-bacteria interactions. However, the complex virulence mechanisms of X. citri subsp. citri are still not well understood. In this study, we characterized the role of PhoP in X. citri subsp. citri using a phoP deletion mutant, ΔphoP. Compared with wild-type strain XHG3, ΔphoP showed reduced motility, biofilm formation, as well as decreased production of cellulase, amylase, and polygalacturonase. In addition, the virulence of ΔphoP on citrus leaves was significantly decreased. To further understand the virulence mechanisms of X. citri subsp. citri, high-throughput RNA sequencing technology (RNA-Seq) was used to compare the transcriptomes of the wild-type and mutant strains. Analysis revealed 1017 differentially-expressed genes (DEGs), of which 614 were up-regulated and 403 were down-regulated in ΔphoP. Gene ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that the DEGs were enriched in flagellar assembly, two-component systems, histidine metabolism, bacterial chemotaxis, ABC transporters, and bacterial secretion systems. Our results showed that PhoP activates the expression of a large set of virulence genes, including 22 type III secretion system genes and 15 type III secretion system effector genes, as well as several genes involved in chemotaxis, and flagellar and histidine biosynthesis. Two-step reverse-transcription polymerase chain reaction analysis targeting 17 genes was used to validate the RNA-seq data, and confirmed that the expression of all 17 genes, except for that of virB1, decreased significantly. Our results suggest that PhoP interacts with a global signaling network to co-ordinate the expression of multiple virulence factors involved in modification and adaption to the host environment during infection.
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Affiliation(s)
- Chudan Wei
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Tian Ding
- Guangzhou Airport Entry-Exit Inspection and Quarantine Bureau, Guangzhou 510800, China.
| | - Changqing Chang
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Guangzhou 510642, China.
| | - Chengpeng Yu
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Xingwei Li
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Qiongguang Liu
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Guangzhou 510642, China.
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Han SW, Lee MA, Yoo Y, Cho MH, Lee SW. Genome-wide Screening to Identify Responsive Regulators Involved in the Virulence of Xanthomonas oryzae pv. oryzae. THE PLANT PATHOLOGY JOURNAL 2019; 35:84-89. [PMID: 30828283 PMCID: PMC6385649 DOI: 10.5423/ppj.nt.09.2018.0193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 06/09/2023]
Abstract
Two-component systems (TCSs) are critical to the pathogenesis of Xanthomonas oryzae pv. oryzae (Xoo). We mutated 55 of 62 genes annotated as responsive regulators (RRs) of TCSs in the genome of Xoo strain PXO99A and identified 9 genes involved in Xoo virulence. Four (rpfG, hrpG, stoS, and detR) of the 9 genes were previously reported as key regulators of Xoo virulence and the other 5 have not been characterized. Lesion lengths on rice leaves inoculated with the mutants were shorter than those of the wild type and were significantly restored with gene complementation. The population density of the 5 mutants in planta was smaller than that of PXO99A at 14 days after inoculation, but the growth curves of the mutants in rich medium were similar to those of the wild type. These newly reported RR genes will facilitate studies on the function of TCSs and of the integrated regulation of TCSs for Xoo pathogenesis.
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Affiliation(s)
- Sang-Wook Han
- Department of Integrative Plant Science, Chung-Ang University, Anseong 17546,
Korea
| | - Mi-Ae Lee
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
- Crop Biotech Institute, Kyung Hee University, Yongin 17104,
Korea
| | - Youngchul Yoo
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
- Crop Biotech Institute, Kyung Hee University, Yongin 17104,
Korea
| | - Man-Ho Cho
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
| | - Sang-Won Lee
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
- Crop Biotech Institute, Kyung Hee University, Yongin 17104,
Korea
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Xu C, Wang Y, Liu S, Xie Q, He N, Shi C, Niu X, He C, Li C, Tao J. RaxM regulates the AvrXa21 (RaxX)-mediated immune response. MOLECULAR PLANT PATHOLOGY 2018; 19:2363-2369. [PMID: 30011129 PMCID: PMC6638069 DOI: 10.1111/mpp.12703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 04/14/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice bacterial blight disease, which causes a reduction in rice production. The interaction between Xoo and rice is a model for the study of the gene-for-gene hypothesis, in which a resistance (R) gene encoding a product interacts with an effector molecule encoded by a corresponding bacterial avirulence (avr) gene. Rice XA21 functions as a plant innate immune receptor (R protein) and recognizes the avirulence protein (RaxX) of Xoo to induce the immune response and cope with pathogen attack. The sulphuration of RaxX by the tyrosine sulphotransferase RaxST is essential to its activity. The expression of raxST is regulated by the RaxH/RaxR and phoP/phoQ two-component systems. However, the regulation of raxX expression remains unclear. Here, we showed that a gene (raxM) encodes a small protein, which functions as a regulator of raxX expression. raxX and raxM are located upstream of raxST. Transcriptional analysis indicates that raxX and raxM are separately transcribed and the promoter of raxX is located at the raxM coding region. The RaxM protein regulates its own and raxX expression, and is required for the XA21-mediated immunity response. Therefore, we identified a regulator of raxX expression and of the Xoo-rice interaction. Our findings suggest that RaxX is not only regulated at the post-translational level, but also at the transcriptional level.
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Affiliation(s)
- Chunli Xu
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Yaxin Wang
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Shiyao Liu
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Qingbiao Xie
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Na He
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Chenyi Shi
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Xiaolei Niu
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Chunxia Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical BioresourcesHainan570228China
- Institute of Tropical Agriculture and ForestryHainan UniversityHaikouHainan570228China
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Phosphodiesterase EdpX1 Promotes Xanthomonas oryzae pv. oryzae Virulence, Exopolysaccharide Production, and Biofilm Formation. Appl Environ Microbiol 2018; 84:AEM.01717-18. [PMID: 30217836 DOI: 10.1128/aem.01717-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/06/2018] [Indexed: 12/22/2022] Open
Abstract
In Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, there are over 20 genes encoding GGDEF, EAL, and HD-GYP domains, which are potentially involved in the metabolism of second messenger c-di-GMP. In this study, we focused on the characterization of an EAL domain protein, EdpX1. Deletion of the edpX1 gene resulted in a 2-fold increase in the intracellular c-di-GMP levels, which were restored to the wild-type levels in the complemented ΔedpX1(pB-edpX1) strain, demonstrating that EdpX1 is an active phosphodiesterase (PDE) in X. oryzae pv. oryzae. In addition, colorimetric assays further confirmed the PDE activity of EdpX1 by showing that the E153A mutation at the EAL motif strongly reduced its activity. Virulence assays on the leaves of susceptible rice showed that the ΔedpX1 mutant was severely impaired in causing disease symptoms. In trans expression of wild-type edpX1, but not edpX1 E153A, was able to complement the weakened virulence phenotype. These results indicated that an active EAL domain is required for EdpX1 to regulate the virulence of X. oryzae pv. oryzae. We then demonstrated that the ΔedpX1 mutant was defective in secreting exopolysaccharide (EPS) and forming biofilms. The expression of edpX1 in the ΔedpX1 mutant, but not edpX1 E153A, restored the defective phenotypes to near-wild-type levels. In addition, we observed that EdpX1-green fluorescent protein (EdpX1-GFP) exhibited multiple subcellular localization foci, and this pattern was dependent on its transmembrane (TM) region, which did not seem to directly contribute to the regulatory function of EdpX1. Thus, we concluded that EdpX1 exhibits PDE activity to control c-di-GMP levels, and its EAL domain is necessary and sufficient for its regulation of virulence in X. oryzae pv. oryzae.IMPORTANCE Bacteria utilize c-di-GMP as a second messenger to regulate various biological functions. The synthesis and degradation of c-di-GMP are catalyzed by GGDEF domains and an EAL or HD-GYP domain, respectively. Multiple genes encoding these domains are often found in one bacterial strain. For example, in the genome of X. oryzae pv. oryzae PXO99A, 26 genes encoding proteins containing these domains were identified. Therefore, to fully appreciate the complexity and specificity of c-di-GMP signaling in X. oryzae pv. oryzae, the enzymatic activities and regulatory functions of each GGDEF, EAL, and HD-GYP domain protein need to be elucidated. In this study, we showed that the EAL domain protein EdpX1 is a major PDE to regulate diverse virulence phenotypes through the c-di-GMP signaling pathway.
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Zhang ZC, Zhao M, Xu LD, Niu XN, Qin HP, Li YM, Li ML, Jiang ZW, Yang X, Huang GH, Jiang W, Tang JL, He YQ. Genome-Wide Screening for Novel Candidate Virulence Related Response Regulator Genes in Xanthomonas oryzae pv. oryzicola. Front Microbiol 2018; 9:1789. [PMID: 30131784 PMCID: PMC6090019 DOI: 10.3389/fmicb.2018.01789] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Two-component regulatory system (TCS), a major type of cellular signal transduction system, is widely used by bacteria to adapt to different conditions and to colonize certain ecological niches in response to environmental stimuli. TCSs are of distinct functional diversity, genetic diversity, and species specificity (pathovar specificity, even strain specificity) across bacterial groups. Although TCSs have been demonstrated to be crucial to the virulence of Xanthomonas, only a few researches have been reported about the studies of TCSs in Xanthomonas oryzae pathovar oryzicola (hereafter Xoc), the pathogen of rice bacterial streak disease. In the genome of Xoc strain GX01, it has been annotated 110 TCSs genes encoding 54 response regulators (RRs), 36 orthodox histidine kinase (HKs) and 20 hybrid histidine kinase (HyHKs). To evaluate the involvement of TCSs in the stress adaptation and virulence of Xoc, we mutated 50 annotated RR genes in Xoc GX01 by homologous vector integration mutagenesis and assessed their phenotypes in given conditions and tested their virulence on host rice. 17 RR genes were identified to be likely involved in virulence of Xoc, of which 10 RR genes are novel virulence genes in Xanthomonas, including three novel virulence genes for bacteria. Of the novel candidate virulence genes, some of which may be involved in the general stress adaptation, exopolysaccharide production, extracellular protease secretion and swarming motility of Xoc. Our results will facilitate further studies on revealing the biological functions of TCS genes in this phytopathogenic bacterium.
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Affiliation(s)
- Zheng-Chun Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China.,College of Agronomy, Guangxi University, Nanning, China
| | - Min Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Li-Dan Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xiang-Na Niu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Hong-Ping Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yi-Ming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Mei-Lin Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Zhong-Wei Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xia Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Guang-Hui Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Wei Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
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Huang YY, Sun YH, Huang N, Liu XX, Yan J, Sun AH. Sublethal β-lactam antibiotics induce PhpP phosphatase expression and StkP kinase phosphorylation in PBP-independent β-lactam antibiotic resistance of Streptococcus pneumoniae. Biochem Biophys Res Commun 2018; 503:2000-2008. [PMID: 30135012 DOI: 10.1016/j.bbrc.2018.07.148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 07/30/2018] [Indexed: 12/16/2022]
Abstract
StkP and PhpP of Streptococcus pneumoniae have been confirmed to compose a signaling couple, in which the former is a serine/threonine (Ser/Thr) kinase while the latter was annotated as a phosphotase. StkP has been reported to be involved in penicillin-binding protein (PBP)-independent penicillin resistance of S. pneumoniae. However, the enzymatic characterization of PhpP and the role of PhpP in StkP-PhpP couple remain poorly understood. Here we showed that 1/4 minimal inhibitory concentration (MIC) of penicillin (PCN) or cefotaxime (CTX), the representatives of β-lactam antibiotics, could induce the expression of stkP and phpP genes and phosphorylation of StkP in PCN/CTX-sensitive strain ATCC6306 and three isolates of S. pneumoniae (MICs: 0.02-0.5 μg/ml). The product of phpP gene hydrolyzed PP2C type Ser/Thr phosphotase-specific RRA (pT)VA phosphopeptide substrate with the Km and Kcat values of 277.35 μmoL/L and 0.71 S-1, and the hydrolytic activity was blocked by sodium fluoride, a PP2C type Ser/Thr phosphatase inhibitor. The phosphorylation levels of StkP in the four phpP gene-knockout (ΔphpP) mutants were significantly higher than that in the wild-type strains. In particular, the MICs of PCN and CTX against the ΔphpP mutants were significantly elevated as 4-16 μg/ml. Therefore, our findings confirmed that sublethal PCN and CTX act as environmental inducers to cause the increase of phpP and stkP gene expression and StkP phosphorylation. PhpP is a PP2C type Ser/Thr protein phosphatase responsible for dephosphorylation of StkP. Knockout of the phpP gene results in a high level of StkP phosphorylation and PBP-independent PCN/CTX resistance of S. pneumoniae.
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Affiliation(s)
- Yan-Ying Huang
- Faculty of Basic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, 310053, PR China; Department of Pathology, Hangzhou Red Cross Hospital, Hangzhou, Zhejiang, 310003, PR China.
| | - Yan-Hong Sun
- Department of Laboratory Medicine, The Children's Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310052, PR China.
| | - Nan Huang
- College of Medical Technology, Zhang Chinese Medical University, Hangzhou, Zhejiang, 310053, PR China.
| | - Xiao-Xiang Liu
- Faculty of Basic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, 310053, PR China.
| | - Jie Yan
- Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, PR China; Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, PR China.
| | - Ai-Hua Sun
- Faculty of Basic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, 310053, PR China.
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Ikawa Y, Ohnishi S, Shoji A, Furutani A, Tsuge S. Concomitant Regulation by a LacI-Type Transcriptional Repressor XylR on Genes Involved in Xylan and Xylose Metabolism and the Type III Secretion System in Rice Pathogen Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:605-613. [PMID: 29360015 DOI: 10.1094/mpmi-11-17-0277-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The hypersensitive response and pathogenicity (hrp) genes of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, encode components of the type III secretion system and are essential for virulence. Expression of hrp genes is regulated by two key hrp regulators, HrpG and HrpX; HrpG regulates hrpX and hrpA, and HrpX regulates the other hrp genes on hrpB-hrpF operons. We previously reported the sugar-dependent quantitative regulation of HrpX; the regulator highly accumulates in the presence of xylose, followed by high hrp gene expression. Here, we found that, in a mutant lacking the LacI-type transcriptional regulator XylR, HrpX accumulation and hrp gene expression were high even in the medium without xylose, reaching the similar levels present in the wild type incubated in the xylose-containing medium. XylR also negatively regulated one of two xylose isomerase genes (xylA2 but not xylA1) by binding to the motif sequence in the upstream region of the gene. Xylose isomerase is an essential enzyme in xylose metabolism and interconverts between xylose and xylulose. Our results suggest that, in the presence of xylose, inactivation of XylR leads to greater xylan and xylose utilization and, simultaneously, to higher accumulation of HrpX, followed by higher hrp gene expression in the bacterium.
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Affiliation(s)
- Yumi Ikawa
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
| | - Sayaka Ohnishi
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
| | - Akiko Shoji
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
| | - Ayako Furutani
- 2 Gene Research Center, Ibaraki University, Inashiki 300-0393, Japan
| | - Seiji Tsuge
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
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Sibanda S, Kwenda S, Tanui CK, Shyntum DY, Coutinho TA, Moleleki LN. Transcriptome Profiling Reveals the EanI/R Quorum Sensing Regulon in Pantoea Ananatis LMG 2665 T. Genes (Basel) 2018; 9:E148. [PMID: 29518982 PMCID: PMC5867869 DOI: 10.3390/genes9030148] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 11/23/2022] Open
Abstract
Pantoea ananatis LMG 2665T synthesizes and utilizes acyl homoserine lactones (AHLs) for signalling. The complete set of genes regulated by the EanI/R quorum sensing (QS) system in this strain is still not fully known. In this study, RNA-sequencing (RNA-seq) was used to identify the EanI/R regulon in LMG 2665T. Pairwise comparisons of LMG 2665T in the absence of AHLs (Optical density (OD)600 = 0.2) and in the presence of AHLs (OD600 = 0.5) were performed. Additionally, pairwise comparisons of LMG 2665T and its QS mutant at OD600 = 0.5 were undertaken. In total, 608 genes were differentially expressed between LMG 2665T at OD600 = 0.5 versus the same strain at OD600 = 0.2 and 701 genes were differentially expressed between LMG 2665T versus its QS mutant at OD600 = 0.5. A total of 196 genes were commonly differentially expressed between the two approaches. These constituted approximately 4.5% of the whole transcriptome under the experimental conditions used in this study. The RNA-seq data was validated by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Genes found to be regulated by EanI/R QS were those coding for redox sensing, metabolism, flagella formation, flagella dependent motility, cell adhesion, biofilm formation, regulators, transport, chemotaxis, methyl accepting proteins, membrane proteins, cell wall synthesis, stress response and a large number of hypothetical proteins. The results of this study give insight into the genes that are regulated by the EanI/R system in LMG 2665T. Functional characterization of the QS regulated genes in LMG 2665T could assist in the formulation of control strategies for this plant pathogen.
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Affiliation(s)
- Siphathele Sibanda
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
- Centre for Microbial Ecology and Genomics (CMEG), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
| | - Stanford Kwenda
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
| | - Collins K Tanui
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
| | - Divine Y Shyntum
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
| | - Teresa A Coutinho
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
- Centre for Microbial Ecology and Genomics (CMEG), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
| | - Lucy N Moleleki
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, 0002 Pretoria, South Africa.
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An Essential Regulatory System Originating from Polygenic Transcriptional Rewiring of PhoP-PhoQ of Xanthomonas campestris. Genetics 2017; 206:2207-2223. [PMID: 28550013 DOI: 10.1534/genetics.117.200204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 05/22/2017] [Indexed: 01/06/2023] Open
Abstract
How essential, regulatory genes originate and evolve is intriguing because mutations of these genes not only lead to lethality in organisms, but also have pleiotropic effects since they control the expression of multiple downstream genes. Therefore, the evolution of essential, regulatory genes is not only determined by genetic variations of their own sequences, but also by the biological function of downstream genes and molecular mechanisms of regulation. To understand the origin of essential, regulatory genes, experimental dissection of the complete regulatory cascade is needed. Here, we provide genetic evidences to reveal that PhoP-PhoQ is an essential two-component signal transduction system in the gram-negative bacterium Xanthomonas campestris, but that its orthologs in other bacteria belonging to Proteobacteria are nonessential. Mutational, biochemical, and chromatin immunoprecipitation together with high-throughput sequencing analyses revealed that phoP and phoQ of X. campestris and its close relative Pseudomonas aeruginosa are replaceable, and that the consensus binding motifs of the transcription factor PhoP are also highly conserved. PhoP Xcc in X. campestris regulates the transcription of a number of essential, structural genes by directly binding to cis-regulatory elements (CREs); however, these CREs are lacking in the orthologous essential, structural genes in P. aeruginosa, and thus the regulatory relationships between PhoP Pae and these downstream essential genes are disassociated. Our findings suggested that the recruitment of regulatory proteins by critical structural genes via transcription factor-CRE rewiring is a driving force in the origin and functional divergence of essential, regulatory genes.
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GamR, the LysR-Type Galactose Metabolism Regulator, Regulates hrp Gene Expression via Transcriptional Activation of Two Key hrp Regulators, HrpG and HrpX, in Xanthomonas oryzae pv. oryzae. Appl Environ Microbiol 2016; 82:3947-3958. [PMID: 27107122 DOI: 10.1128/aem.00513-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight of rice. For the virulence of the bacterium, the hrp genes, encoding components of the type III secretion system, are indispensable. The expression of hrp genes is regulated by two key hrp regulators, HrpG and HrpX: HrpG regulates hrpX, and HrpX regulates other hrp genes. Several other regulators have been shown to be involved in the regulation of hrp genes. Here, we found that a LysR-type transcriptional regulator that we named GamR, encoded by XOO_2767 of X. oryzae pv. oryzae strain MAFF311018, positively regulated the transcription of both hrpG and hrpX, which are adjacent to each other but have opposite orientations, with an intergenic upstream region in common. In a gel electrophoresis mobility shift assay, GamR bound directly to the middle of the upstream region common to hrpG and hrpX The loss of either GamR or its binding sites decreased hrpG and hrpX expression. Also, GamR bound to the upstream region of either a galactose metabolism-related gene (XOO_2768) or a galactose metabolism-related operon (XOO_2768 to XOO_2771) located next to gamR itself and positively regulated the genes. The deletion of the regulator gene resulted in less bacterial growth in a synthetic medium with galactose as a sole sugar source. Interestingly, induction of the galactose metabolism-related gene was dependent on galactose, while that of the hrp regulator genes was galactose independent. Our results indicate that the LysR-type transcriptional regulator that regulates the galactose metabolism-related gene(s) also acts in positive regulation of two key hrp regulators and the following hrp genes in X. oryzae pv. oryzae. IMPORTANCE The expression of hrp genes encoding components of the type III secretion system is essential for the virulence of many plant-pathogenic bacteria, including Xanthomonas oryzae pv. oryzae. It is specifically induced during infection. Research has revealed that in this bacterium, hrp gene expression is controlled by two key hrp regulators, HrpG and HrpX, along with several other regulators in the complex regulatory network, but the details remain unclear. Here, we found that a novel LysR-type transcriptional activator, named GamR, functions as an hrp regulator by directly activating the transcription of both hrpG and hrpX Interestingly, GamR also regulates a galactose metabolism-related gene (or operon) in a galactose-dependent manner, while the regulation of hrpG and hrpX is independent of the sugar. Our finding of a novel hrp regulator that directly and simultaneously regulates two key hrp regulators provides new insights into an important and complex regulation system of X. oryzae pv. oryzae hrp genes.
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Su J, Zou X, Huang L, Bai T, Liu S, Yuan M, Chou SH, He YW, Wang H, He J. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice. Sci Rep 2016; 6:25978. [PMID: 27193392 PMCID: PMC4872155 DOI: 10.1038/srep25978] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/26/2016] [Indexed: 12/28/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases.
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Affiliation(s)
- Jianmei Su
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xia Zou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Liangbo Huang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Tenglong Bai
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Meng Yuan
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510650, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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Liu MC, Tsai YL, Huang YW, Chen HY, Hsueh PR, Lai SY, Chen LC, Chou YH, Lin WY, Liaw SJ. Stenotrophomonas maltophilia PhoP, a Two-Component Response Regulator, Involved in Antimicrobial Susceptibilities. PLoS One 2016; 11:e0153753. [PMID: 27159404 PMCID: PMC4861329 DOI: 10.1371/journal.pone.0153753] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 04/04/2016] [Indexed: 01/02/2023] Open
Abstract
Stenotrophomonas maltophilia, a gram-negative bacterium, has increasingly emerged as an important nosocomial pathogen. It is well-known for resistance to a variety of antimicrobial agents including cationic antimicrobial polypeptides (CAPs). Resistance to polymyxin B, a kind of CAPs, is known to be controlled by the two-component system PhoPQ. To unravel the role of PhoPQ in polymyxin B resistance of S. maltophilia, a phoP mutant was constructed. We found MICs of polymyxin B, chloramphenicol, ampicillin, gentamicin, kanamycin, streptomycin and spectinomycin decreased 2-64 fold in the phoP mutant. Complementation of the phoP mutant by the wild-type phoP gene restored all of the MICs to the wild type levels. Expression of PhoP was shown to be autoregulated and responsive to Mg2+ levels. The polymyxin B and gentamicin killing tests indicated that pretreatment of low Mg2+ can protect the wild-type S. maltophilia from killing but not phoP mutant. Interestingly, we found phoP mutant had a decrease in expression of SmeZ, an efflux transporter protein for aminoglycosides in S. maltophilia. Moreover, phoP mutant showed increased permeability in the cell membrane relative to the wild-type. In summary, we demonstrated the two-component regulator PhoP of S. maltophilia is involved in antimicrobial susceptibilities and low Mg2+ serves as a signal for triggering the pathway. Both the alteration in membrane permeability and downregulation of SmeZ efflux transporter in the phoP mutant contributed to the increased drug susceptibilities of S. maltophilia, in particular for aminoglycosides. This is the first report to describe the role of the Mg2+-sensing PhoP signaling pathway of S. maltophilia in regulation of the SmeZ efflux transporter and in antimicrobial susceptibilities. This study suggests PhoPQ TCS may serve as a target for development of antimicrobial agents against multidrug-resistant S. maltophilia.
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Affiliation(s)
- Ming-Che Liu
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Yi-Lin Tsai
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Yi-Wei Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Hsing-Yu Chen
- Department of Clinical Pathology, Taipei City Hospital Renai Branch, Taipei, Taiwan, Republic of China
| | - Po-Ren Hsueh
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, Republic of China
| | - Szu-Yu Lai
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Li-Chia Chen
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Yi-Hwa Chou
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Wen-Yuan Lin
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Shwu-Jen Liaw
- Department and Graduate Institute of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, Republic of China
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29
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Nguyen MP, Park J, Cho MH, Lee SW. Role of DetR in defence is critical for virulence of Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT PATHOLOGY 2016; 17:601-13. [PMID: 26315668 PMCID: PMC6638461 DOI: 10.1111/mpp.12305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Like other bacteria, Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight disease in rice, possesses intracellular signalling systems, known as two-component regulatory systems (TCSs), which regulate pathogenesis and biological processes. Completion of the genome sequences of three Xoo strains has facilitated the functional study of genes, including those of TCSs, but the biological functions of most Xoo TCSs have not yet been uncovered. To identify TCSs involved in Xoo pathogenesis, we generated knockout strains lacking response regulators (RRs, a cytoplasmic signalling component of the TCS) and examined the virulence of the RR knockout strains. This study presents a knockout strain (detR(-) ) lacking the PXO_04659 gene which shows dramatically reduced virulence relative to the wild-type. Our studies to elucidate detR function in Xoo pathogenesis revealed a reduction in extracellular polysaccharide (EPS), intolerance to reactive oxygen species (ROS) and deregulation of iron homeostasis in the detR(-) strain. Moreover, gene expression of regulatory factors, including other RRs and transcription factors (TFs), was altered in the absence of DetR protein, as determined by reverse transcription-polymerase chain reaction (RT-PCR) and/or real-time quantitative RT-PCR analyses. All evidence leads to the conclusion that DetR is essential for Xoo virulence through the regulation of the Xoo defence system including EPS synthesis, ROS detoxification and iron homeostasis, solely or cooperatively with other regulatory factors.
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Affiliation(s)
- Minh-Phuong Nguyen
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
- Institute of Crop Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
| | - Jongchan Park
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
- Institute of Crop Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
| | - Man-Ho Cho
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
| | - Sang-Won Lee
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
- Institute of Crop Biotechnology, Kyung Hee University, Yongin, 446-701, South Korea
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30
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Ikawa Y, Tsuge S. The quantitative regulation of the hrp regulator HrpX is involved in sugar-source-dependent hrp gene expression in Xanthomonas oryzae pv. oryzae. FEMS Microbiol Lett 2016; 363:fnw071. [PMID: 27020414 DOI: 10.1093/femsle/fnw071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2016] [Indexed: 12/21/2022] Open
Abstract
In Xanthomonas oryzae pv. oryzae, the pathogen of bacterial leaf blight of rice, hrp gene expression is regulated by the key hrp regulators HrpG and HrpX. HrpG regulates hrpX and hrpA, and HrpX regulates the other hrp genes on hrpB-hrpF operons. We previously examined the expression of the HrpX-regulated hrp gene hrcU and demonstrated that hrp gene expression is highly induced in a certain nutrient-poor medium containing xylose. In the present study, we found that the induction level of HrpX-regulated hrp genes was higher in medium with xylose than in media with any other sugar sources (glucose, sucrose and fructose), but that expression of hrpG, hrpX and hrpA was independent of the sugar sources. In western blot analysis, the accumulation of HrpX was reduced in media with a sugar other than xylose, probably as a result of proteolysis, but the addition of xylose canceled this reduced accumulation of the protein. The results suggest that proteolysis of HrpX is an important hrp regulatory mechanism and that xylose specifically suppresses this proteolysis, resulting in active hrp gene expression in X. oryzae pv. oryzae.
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Affiliation(s)
- Yumi Ikawa
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan
| | - Seiji Tsuge
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan
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Zheng D, Yao X, Duan M, Luo Y, Liu B, Qi P, Sun M, Ruan L. Two overlapping two-component systems in Xanthomonas oryzae pv. oryzae contribute to full fitness in rice by regulating virulence factors expression. Sci Rep 2016; 6:22768. [PMID: 26957113 PMCID: PMC4783713 DOI: 10.1038/srep22768] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/19/2016] [Indexed: 01/17/2023] Open
Abstract
Two-component signal transduction systems (TCSs) are widely used by bacteria to adapt to the environment. In the present study, StoS (stress tolerance-related oxygen sensor) and SreKRS (salt response kinase, regulator, and sensor) were found to positively regulate extracellular polysaccharide (EPS) production and swarming in the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo). Surprisingly, the absence of stoS or sreKRS did not attenuate virulence. To better understand the intrinsic functions of StoS and SreKRS, quantitative proteomics isobaric tags for relative and absolute quantitation (iTRAQ) was employed. Consistent with stoS and sreK mutants exhibiting a similar phenotype, the signalling circuits of StoS and SreKRS overlapped. Carbohydrate metabolism proteins and chemotaxis proteins, which could be responsible for EPS and swarming regulation, respectively, were reprogrammed in stoS and sreK mutants. Moreover, StoS and SreKRS demonstrated moderate expression of the major virulence factor, hypersensitive response and pathogenicity (Hrp) proteins through the HrpG-HrpX circuit. Most importantly, Xoo equipped with StoS and SreKRS outcompetes strains without StoS or SreKRS in co-infected rice and grows outside the host. Therefore, we propose that StoS and SreKRS adopt a novel strategy involving the moderation of Hrp protein expression and the promotion of EPS and motility to adapt to the environment.
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Affiliation(s)
- Dehong Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xiaoyan Yao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Meng Duan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yufeng Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Biao Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Pengyuan Qi
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
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Transcriptome-Based Identification of Differently Expressed Genes from Xanthomonas oryzae pv. oryzae Strains Exhibiting Different Virulence in Rice Varieties. Int J Mol Sci 2016; 17:259. [PMID: 26907259 PMCID: PMC4783988 DOI: 10.3390/ijms17020259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 01/30/2016] [Accepted: 02/16/2016] [Indexed: 11/16/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB) in rice (Oryza sativa L.). In this study, we investigated the genome-wide transcription patterns of two Xoo strains (KACC10331 and HB1009), which showed different virulence patterns against eight rice cultivars, including IRBB21 (carrying Xa21). In total, 743 genes showed a significant change (p-value < 0.001 in t-tests) in their mRNA expression levels in the HB1009 (K3a race) strain compared with the Xoo KACC10331 strain (K1 race). Among them, four remarkably enriched GO terms, DNA binding, transposition, cellular nitrogen compound metabolic process, and cellular macromolecule metabolic process, were identified in the upregulated genes. In addition, the expression of 44 genes was considerably higher (log2 fold changes > 2) in the HB1009 (K3a race) strain than in the Xoo KACC10331 (K1 race) strain. Furthermore, 13 and 12 genes involved in hypersensitive response and pathogenicity (hrp) and two-component regulatory systems (TCSs), respectively, were upregulated in the HB1009 (K3a race) strain compared with the Xoo KACC10331 (K1 race) strain, which we determined using either quantitative real-time PCR analysis or next-generation RNA sequencing. These results will be helpful to improve our understanding of Xoo and to gain a better insight into the Xoo–rice interactions.
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Potnis N, Timilsina S, Strayer A, Shantharaj D, Barak JD, Paret ML, Vallad GE, Jones JB. Bacterial spot of tomato and pepper: diverse Xanthomonas species with a wide variety of virulence factors posing a worldwide challenge. MOLECULAR PLANT PATHOLOGY 2015; 16:907-20. [PMID: 25649754 PMCID: PMC6638463 DOI: 10.1111/mpp.12244] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
TAXONOMIC STATUS Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; Species Xanthomonas euvesicatoria, Xanthomonas vesicatoria, Xanthomonas perforans and Xanthomonas gardneri. MICROBIOLOGICAL PROPERTIES Gram-negative, rod-shaped bacterium, aerobic, motile, single polar flagellum. HOST RANGE Causes bacterial spot disease on plants belonging to the Solanaceae family, primarily tomato (Solanum lycopersicum), pepper (Capsicum annuum) and chilli peppers (Capsicum frutescens). DISEASE SYMPTOMS Necrotic lesions on all above-ground plant parts. DISTRIBUTION Worldwide distribution of X. euvesicatoria and X. vesicatoria on tomato and pepper; X. perforans and X. gardneri increasingly being isolated from the USA, Canada, South America, Africa and Europe. A wide diversity within the bacterial spot disease complex, with an ability to cause disease at different temperatures, makes this pathogen group a worldwide threat to tomato and pepper production. Recent advances in genome analyses have revealed the evolution of the pathogen with a plethora of novel virulence factors. Current management strategies rely on the use of various chemical control strategies and sanitary measures to minimize pathogen spread through contaminated seed. Chemical control strategies have been a challenge because of resistance by the pathogen. Breeding programmes have been successful in developing commercial lines with hypersensitive and quantitative resistance. However, durability of resistance has been elusive. Recently, a transgenic approach has resulted in the development of tomato genotypes with significant levels of resistance and improved yield that hold promise. In this article, we discuss the current taxonomic status, distribution of the four species, knowledge of virulence factors, detection methods and strategies for disease control with possible directions for future research.
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Affiliation(s)
- Neha Potnis
- Department of Plant Pathology, Fifield Hall, University of Florida, Gainesville, FL, 32611, USA
| | - Sujan Timilsina
- Department of Plant Pathology, Fifield Hall, University of Florida, Gainesville, FL, 32611, USA
| | - Amanda Strayer
- Department of Plant Pathology, Fifield Hall, University of Florida, Gainesville, FL, 32611, USA
| | - Deepak Shantharaj
- Department of Plant Pathology, Fifield Hall, University of Florida, Gainesville, FL, 32611, USA
| | - Jeri D Barak
- Department of Plant Pathology, Russell Laboratories, University of Wisconsin, Madison, WI, 53706, USA
| | - Mathews L Paret
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, 33598, USA
| | - Gary E Vallad
- North Florida Research & Education Center, University of Florida, Quincy, FL, 32351-5677, USA
| | - Jeffrey B Jones
- Department of Plant Pathology, Fifield Hall, University of Florida, Gainesville, FL, 32611, USA
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Sahebi M, Taheri E, Tarighi S. CitB is required for full virulence of Xanthomonas oryzae pv. oryzae. World J Microbiol Biotechnol 2015; 31:1619-27. [PMID: 26250545 DOI: 10.1007/s11274-015-1914-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 07/29/2015] [Indexed: 11/28/2022]
Abstract
To identify novel virulence associated genes in Xanthomonas oryzae pv. oryzae (Xoo), a Xoo isolate (XooIR42), obtained from north of Iran, was selected to generate a mini-Tn5 transposon mutation library. One mutant (XooM176) that indicated reduced virulence on rice plants, while grew similar to wild type was selected. This mutant had an insertion in a coding region with 96% amino acid identity to a response regulator of Xoo KACC10331, citB (Xoo_RS12710). Genome analysis of Xoo KACC10331 indicated several genes including a flagelin protein (FlgL) and a chemotaxis protein (Xoo_RS12720) which were identified as virulence genes 4297 and 1403 nucleotides from the citB, respectively. The swarming motility, resistance to hydrogen peroxide, induced a hypersensitive response, in planta growth and pathogenicity were reduced in XooM176 mutant compared to that of wild-type. A plasmid containing the full citB gene of Xoo KACC10331was sufficient to complement the XooM176 mutant for lesion formation and resistance to hydrogen peroxide. We therefore propose that Xoo requires CitB for full pathogenicity in rice plants and also for protection against oxidative stress.
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Affiliation(s)
- Masood Sahebi
- Laboratory of Phytopathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Elaheh Taheri
- Laboratory of Phytopathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Saeed Tarighi
- Laboratory of Phytopathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran.
- Laboratory of Plant Pathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran.
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Xu H, Zhao Y, Qian G, Liu F. XocR, a LuxR solo required for virulence in Xanthomonas oryzae pv. oryzicola. Front Cell Infect Microbiol 2015; 5:37. [PMID: 25932456 PMCID: PMC4399327 DOI: 10.3389/fcimb.2015.00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/31/2015] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas oryzae pv. oryzicola (Xoc) causes bacterial leaf streak (BLS) in rice, a serious bacterial disease of rice in Asia and parts of Africa. The virulence mechanisms of Xoc are not entirely clear and control measures for BLS are poorly developed. The solo LuxR proteins are widespread and shown to be involved in virulence in some plant associated bacteria (PAB). Here, we have cloned and characterized a PAB LuxR solo from Xoc, named as XocR. Mutation of xocR almost completely impaired the virulence ability of Xoc on host rice, but did not alter the ability to trigger HR (hypersensitive response, a programmed cell death) on non-host (plant) tobacco, suggesting the diversity of function of xocR in host and non-host plants. We also provide evidence to show that xocR is involved in the regulation of growth-independent cell motility in response to a yet-to-be-identified rice signal, as mutation of xocR impaired cell swimming motility of wild-type Rs105 in the presence but not absence of rice macerate. We further found that xocR regulated the transcription of two characterized virulence-associated genes (recN and trpE) in the presence of rice macerate. The promoter regions of recN and trpE possessed a potential binding motif (an imperfect pip box-like element) of XocR, raising the possibility that XocR might directly bind the promoter regions of these two genes to regulate their transcriptional activity. Our studies add a new member of PAB LuxR solos and also provide new insights into the role of PAB LuxR solo in the virulence of Xanthomonas species.
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Affiliation(s)
- Huiyong Xu
- Institute of Plant Protection, Jiangsu Academy of Agricultural ScienceNanjing, China
- College of Plant Protection, Nanjing Agricultural UniversityNanjing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing, China
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural ScienceNanjing, China
| | - Guoliang Qian
- College of Plant Protection, Nanjing Agricultural UniversityNanjing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing, China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural ScienceNanjing, China
- College of Plant Protection, Nanjing Agricultural UniversityNanjing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing, China
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Noh YH, Kim SY, Han JW, Seo YS, Cha JS. Expression of colSR Genes Increased in the rpf Mutants of Xanthomonas oryzae pv. oryzae KACC10859. THE PLANT PATHOLOGY JOURNAL 2014; 30:304-309. [PMID: 25289017 PMCID: PMC4181107 DOI: 10.5423/ppj.nt.12.2013.0122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 05/25/2014] [Accepted: 05/25/2014] [Indexed: 06/03/2023]
Abstract
The rpf genes and colS XOO1207/colR XOO1208 were known to require for virulence of Xanthomonas oryzae pv. oryzae (Xoo). In Xoo KACC10331 genome, two more colS/colR genes, colS XOO3534 (raxH)/colR XOO3535 (raxR) and colS XOO3762/colR XOO3763 were annotated. The colS XOO3534/colR XOO3535 were known to control AvrXa21 activity and functions of colS XOO3762/colR XOO3763 were unknown in Xoo. To characterize the relationship between rpf and colS/colR genes, expression of colS/colR genes in Rpf mutants of Xoo were analyzed with quantitative reverse transcription PCR (qRT-PCR). Expressions of all three colS/colR genes increased in the rpfF mutant in which DSF synthesis is defective. Expression of colS XOO1207/colR XOO1208, colS XOO3534/colR XOO3535 and colS XOO3762/colR XOO3763 increased 2, 2-7, 3-13 folds respectively. Expression of colS XOO3534 and colS XOO3762 also increased 2-4 folds in the rpfG mutant in which the signal from DSF is no longer transferred to down-stream. Expression of the other colS/colR genes was not significantly changed in the rpfG mutant compared to the wild type. Since RpfF and RpfG are responsible for DSF synthesis and signal transfer from DSF to down-stream to regulate virulence gene expression, these results suggest that the DSF and DSF-mediated signal regulate negatively three colS/colR genes in Xoo.
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Affiliation(s)
- Young-Hee Noh
- Department of Plant Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Korea
| | - Sun-Young Kim
- Department of Microbiology, Pusan National University, Busan 609-735, Korea
| | - Jong-Woo Han
- Watermelon Research Institute, Chungbuk ARES, Cheongwon, Chungbuk 363-883, Korea
| | - Young-Su Seo
- Department of Microbiology, Pusan National University, Busan 609-735, Korea
| | - Jae-Soon Cha
- Department of Plant Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Korea
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Ikawa Y, Furutani A, Ochiai H, Tsuge S. StoS, a hybrid histidine kinase sensor of Xanthomonas oryzae pv. oryzae, is activated by sensing low O₂ concentration and is involved in stress tolerance and virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:537-45. [PMID: 24520898 DOI: 10.1094/mpmi-09-13-0263-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Bacteria have two-component signal transduction systems (TCSTS), which are important devices for receiving various environmental signals. A TCSTS generally consists of a sensor histidine kinase (HK) and a response regulator (RR) that contains a receiver domain. There are also hybrid-type HK (HyHK) that comprise a HK with a receiver domain within one molecule. In this study, we show that the deletion mutant of a HyHK XOO_0635 (StoS) of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, had decreased stress tolerance to high osmolarity, sodium, and H₂O₂. Growth of the StoS mutant was delayed, and viability was lower than the wild type in medium and in rice leaves. We found that StoS regulates the expression of various genes including XOO_3715, XOO_0131, and stoS itself. A domain search revealed a PAS domain with a heme pocket in StoS, implying that the HyHK functions as an O₂ sensor. When the bacteria were incubated in low oxygen, the StoS-dependent expression of XOO_0131 and XOO_3715 became higher. Therefore, StoS is activated by sensing a low O2 concentration in its environs and is involved in gene expression for adapting to various stressful conditions.
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Jalan N, Kumar D, Andrade MO, Yu F, Jones JB, Graham JH, White FF, Setubal JC, Wang N. Comparative genomic and transcriptome analyses of pathotypes of Xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range. BMC Genomics 2013; 14:551. [PMID: 23941402 PMCID: PMC3751643 DOI: 10.1186/1471-2164-14-551] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 08/06/2013] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Citrus bacterial canker is a disease that has severe economic impact on citrus industries worldwide and is caused by a few species and pathotypes of Xanthomonas. X. citri subsp. citri strain 306 (XccA306) is a type A (Asiatic) strain with a wide host range, whereas its variant X. citri subsp. citri strain A(w)12879 (Xcaw12879, Wellington strain) is restricted to Mexican lime. RESULTS To characterize the mechanism for the differences in host range of XccA and Xcaw, the genome of Xcaw12879 that was completed recently was compared with XccA306 genome. Effectors xopAF and avrGf1 are present in Xcaw12879, but were absent in XccA306. AvrGf1 was shown previously for Xcaw to cause hypersensitive response in Duncan grapefruit. Mutation analysis of xopAF indicates that the gene contributes to Xcaw growth in Mexican lime but does not contribute to the limited host range of Xcaw. RNA-Seq analysis was conducted to compare the expression profiles of Xcaw12879 and XccA306 in Nutrient Broth (NB) medium and XVM2 medium, which induces hrp gene expression. Two hundred ninety two and 281 genes showed differential expression in XVM2 compared to in NB for XccA306 and Xcaw12879, respectively. Twenty-five type 3 secretion system genes were up-regulated in XVM2 for both XccA and Xcaw. Among the 4,370 common genes of Xcaw12879 compared to XccA306, 603 genes in NB and 450 genes in XVM2 conditions were differentially regulated. Xcaw12879 showed higher protease activity than XccA306 whereas Xcaw12879 showed lower pectate lyase activity in comparison to XccA306. CONCLUSIONS Comparative genomic analysis of XccA306 and Xcaw12879 identified strain specific genes. Our study indicated that AvrGf1 contributes to the host range limitation of Xcaw12879 whereas XopAF contributes to virulence. Transcriptome analyses of XccA306 and Xcaw12879 presented insights into the expression of the two closely related strains of X. citri subsp. citri. Virulence genes including genes encoding T3SS components and effectors are induced in XVM2 medium. Numerous genes with differential expression in Xcaw12879 and XccA306 were identified. This study provided the foundation to further characterize the mechanisms for virulence and host range of pathotypes of X. citri subsp. citri.
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Affiliation(s)
- Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Dibyendu Kumar
- Waksman Genomics Core Facility, Rutgers University Busch Campus, Piscataway, NJ 08854, USA
| | - Maxuel O Andrade
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Fahong Yu
- ICBR, University of Florida, Gainesville, FL 32611, USA
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - James H Graham
- Department of Soil and Water Science, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Frank F White
- Department of Plant Pathology, Kansas State University, 4024 Throckmorton Hall, Manhattan, KS 66506, USA
| | - João C Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060-0477, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
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Zhang F, Du Z, Huang L, Cruz CV, Zhou Y, Li Z. Comparative transcriptome profiling reveals different expression patterns in Xanthomonas oryzae pv. oryzae strains with putative virulence-relevant genes. PLoS One 2013; 8:e64267. [PMID: 23734193 PMCID: PMC3667120 DOI: 10.1371/journal.pone.0064267] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/10/2013] [Indexed: 11/18/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice bacterial blight, which is a major rice disease in tropical Asian countries. An attempt has been made to investigate gene expression patterns of three Xoo strains on the minimal medium XOM2, PXO99 (P6) and PXO86 (P2) from the Philippines, and GD1358 (C5) from China, which exhibited different virulence in 30 rice varieties, with putative virulence factors using deep sequencing. In total, 4,781 transcripts were identified in this study, and 1,151 and 3,076 genes were differentially expressed when P6 was compared with P2 and with C5, respectively. Our results indicated that Xoo strains from different regions exhibited distinctly different expression patterns of putative virulence-relevant genes. Interestingly, 40 and 44 genes involved in chemotaxis and motility exhibited higher transcript alterations in C5 compared with P6 and P2, respectively. Most other genes associated with virulence, including exopolysaccharide (EPS) synthesis, Hrp genes and type III effectors, including Xanthomonas outer protein (Xop) effectors and transcription activator-like (TAL) effectors, were down-regulated in C5 compared with P6 and P2. The data were confirmed by real-time quantitative RT-PCR, tests of bacterial motility, and enzyme activity analysis of EPS and xylanase. These results highlight the complexity of Xoo and offer new avenues for improving our understanding of Xoo-rice interactions and the evolution of Xoo virulence.
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Affiliation(s)
- Fan Zhang
- Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhenglin Du
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Liyu Huang
- Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Casiana Vera Cruz
- International Rice Research Institute, Metro Manila, The Philippines
| | - Yongli Zhou
- Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail:
| | - Zhikang Li
- Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
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The HD-GYP domain protein RpfG of Xanthomonas oryzae pv. oryzicola regulates synthesis of extracellular polysaccharides that contribute to biofilm formation and virulence on rice. PLoS One 2013; 8:e59428. [PMID: 23544067 PMCID: PMC3609779 DOI: 10.1371/journal.pone.0059428] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 02/14/2013] [Indexed: 11/19/2022] Open
Abstract
Bacterial leaf streak caused by Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most important diseases in rice. However, little is known about the pathogenicity mechanisms of Xoc. Here we have investigated the function of three HD-GYP domain regulatory proteins in biofilm formation, the synthesis of virulence factors and virulence of Xoc. Deletion of rpfG resulted in altered production of extracellular polysaccharides (EPS), abolished virulence on rice and enhanced biofilm formation, but had little effect on the secretion of proteases and motility. In contrast, mutational analysis showed that the other two HD-GYP domain proteins had no effect on virulence factor synthesis and tested phenotypes. Mutation of rpfG led to up-regulation of the type III secretion system and altered expression of three putative glycosyltransferase genes gumD, pgaC and xagB, which are part of operons directing the synthesis of different extracellular polysaccharides. The pgaABCD and xagABCD operons were greatly up-regulated in the Xoc ΔrpfG mutant, whereas the expression of the gum genes was unaltered or slightly enhanced. The elevated biofilm formation of the Xoc ΔrpfG mutant was dramatically reduced upon deletion of gumD, xagA and xagB, but not when pgaA and pgaC were deleted. Interestingly, only the ΔgumD mutant, among these single gene mutants, exhibits multiple phenotype alterations including reduced biofilm and EPS production and attenuated virulence on rice. These data indicate that RpfG is a global regulator that controls biofilm formation, EPS production and bacterial virulence in Xoc and that both gumD- and xagB-dependent EPS contribute to biofilm formation under different conditions.
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Qian G, Liu C, Wu G, Yin F, Zhao Y, Zhou Y, Zhang Y, Song Z, Fan J, Hu B, Liu F. AsnB, regulated by diffusible signal factor and global regulator Clp, is involved in aspartate metabolism, resistance to oxidative stress and virulence in Xanthomonas oryzae pv. oryzicola. MOLECULAR PLANT PATHOLOGY 2013; 14:145-57. [PMID: 23157387 PMCID: PMC6638903 DOI: 10.1111/j.1364-3703.2012.00838.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Xanthomonas oryzae pv. oryzicola (Xoc) causes bacterial leaf streak in rice, which is a destructive disease worldwide. Xoc virulence factors are regulated by diffusible signal factor (DSF) and the global regulator Clp. In this study, we have demonstrated that asnB (XOC_3054), encoding an asparagine synthetase, is a novel virulence-related gene regulated by both DSF and Clp in Xoc. A sequence analysis revealed that AsnB is highly conserved in Xanthomonas. An asnB mutation in Xoc dramatically impaired pathogen virulence and growth rate in host rice, but did not affect the ability to trigger the hypersensitive response in nonhost (plant) tobacco. Compared with the wild-type strain, the asnB deletion mutant was unable to grow in basic MMX (-) medium (a minimal medium without ammonium sulphate as the nitrogen source) with or without 10 tested nitrogen sources, except asparagine. The disruption of asnB impaired pathogen resistance to oxidative stress and reduced the transcriptional expression of oxyR, katA and katG, which encode three important proteins responsible for hydrogen peroxide (H(2)O(2)) sensing and detoxification in Xanthomonas in the presence of H(2)O(2), and nine important known Xoc virulence-related genes in plant cell-mimicking medium. Furthermore, the asnB mutation did not affect extracellular protease activity, extracellular polysaccharide production, motility or chemotaxis. Taken together, our results demonstrate the role of asnB in Xanthomonas for the first time.
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Affiliation(s)
- Guoliang Qian
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
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Afroz A, Zahur M, Zeeshan N, Komatsu S. Plant-bacterium interactions analyzed by proteomics. FRONTIERS IN PLANT SCIENCE 2013; 4:21. [PMID: 23424014 PMCID: PMC3573209 DOI: 10.3389/fpls.2013.00021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/29/2013] [Indexed: 05/04/2023]
Abstract
The evolution of the plant immune response has resulted in a highly effective defense system that is able to resist potential attack by microbial pathogens. The primary immune response is referred to as pathogen associated molecular pattern (PAMP) triggered immunity and has evolved to recognize common features of microbial pathogens. In response to the delivery of pathogen effector proteins, plants acquired R proteins to fight against pathogen attack. R-dependent defense response is important in understanding the biochemical and cellular mechanisms and underlying these interactions will enable molecular and transgenic approaches for crops with increased biotic resistance. Proteomic analyses are particularly useful for understanding the mechanisms of host plant against the pathogen attack. Recent advances in the field of proteome analyses have initiated a new research area, i.e., the analysis of more complex microbial communities and their interaction with plant. Such areas hold great potential to elucidate, not only the interactions between bacteria and their host plants, but also of bacteria-bacteria interactions between different bacterial taxa, symbiotic, pathogenic bacteria, and commensal bacteria. During biotic stress, plant hormonal signaling pathways prioritizes defense over other cellular functions. Some plant pathogens take advantage of hormone dependent regulatory system by mimicking hormones that interfere with host immune responses to promote virulence (vir). In this review, it is discussed the cross talk that plays important role in response to pathogens attack with different infection strategies using proteomic approaches.
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Affiliation(s)
- Amber Afroz
- Department of Biochemistry and Molecular Biology, Nawaz Sharif Medical College, University of Gujrat, Hafiz Hayat Campus GujratGujrat, Pakistan
- *Correspondence: Amber Afroz, Department of Biochemistry and Molecular Biology, Nawaz Sharif Medical College, University of Gujrat, Hafiz Hayat Campus Gujrat, Gujrat, Pakistan. e-mail:
| | - Muzna Zahur
- Department of Biochemistry and Molecular Biology, Nawaz Sharif Medical College, University of Gujrat, Hafiz Hayat Campus GujratGujrat, Pakistan
| | - Nadia Zeeshan
- Department of Biochemistry and Molecular Biology, Nawaz Sharif Medical College, University of Gujrat, Hafiz Hayat Campus GujratGujrat, Pakistan
| | - Setsuko Komatsu
- National Institute of Crop Science, National Agriculture and Food Research OrganizationTsukuba, Japan
- Setsuko Komatsu, National Institute of Crop Science, National Agriculture and Food Research Organization, 2-1-18 Kannondai, Tsukuba 305-8518, Japan. e-mail:
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Newman MA, Sundelin T, Nielsen JT, Erbs G. MAMP (microbe-associated molecular pattern) triggered immunity in plants. FRONTIERS IN PLANT SCIENCE 2013; 4:139. [PMID: 23720666 PMCID: PMC3655273 DOI: 10.3389/fpls.2013.00139] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/23/2013] [Indexed: 05/18/2023]
Abstract
Plants are sessile organisms that are under constant attack from microbes. They rely on both preformed defenses, and their innate immune system to ward of the microbial pathogens. Preformed defences include for example the cell wall and cuticle, which act as physical barriers to microbial colonization. The plant immune system is composed of surveillance systems that perceive several general microbe elicitors, which allow plants to switch from growth and development into a defense mode, rejecting most potentially harmful microbes. The elicitors are essential structures for pathogen survival and are conserved among pathogens. The conserved microbe-specific molecules, referred to as microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs), are recognized by the plant innate immune systems pattern recognition receptors (PRRs). General elicitors like flagellin (Flg), elongation factor Tu (EF-Tu), peptidoglycan (PGN), lipopolysaccharides (LPS), Ax21 (Activator of XA21-mediated immunity in rice), fungal chitin, and β-glucans from oomycetes are recognized by plant surface localized PRRs. Several of the MAMPs and their corresponding PRRs have, in recent years, been identified. This review focuses on the current knowledge regarding important MAMPs from bacteria, fungi, and oomycetes, their structure, the plant PRRs that recognizes them, and how they induce MAMP-triggered immunity (MTI) in plants.
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Affiliation(s)
- Mari-Anne Newman
- *Correspondence: Mari-Anne Newman, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. e-mail:
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Pieretti I, Royer M, Barbe V, Carrere S, Koebnik R, Couloux A, Darrasse A, Gouzy J, Jacques MA, Lauber E, Manceau C, Mangenot S, Poussier S, Segurens B, Szurek B, Verdier V, Arlat M, Gabriel DW, Rott P, Cociancich S. Genomic insights into strategies used by Xanthomonas albilineans with its reduced artillery to spread within sugarcane xylem vessels. BMC Genomics 2012; 13:658. [PMID: 23171051 PMCID: PMC3542200 DOI: 10.1186/1471-2164-13-658] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 11/18/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Xanthomonas albilineans causes leaf scald, a lethal disease of sugarcane. X. albilineans exhibits distinctive pathogenic mechanisms, ecology and taxonomy compared to other species of Xanthomonas. For example, this species produces a potent DNA gyrase inhibitor called albicidin that is largely responsible for inducing disease symptoms; its habitat is limited to xylem; and the species exhibits large variability. A first manuscript on the complete genome sequence of the highly pathogenic X. albilineans strain GPE PC73 focused exclusively on distinctive genomic features shared with Xylella fastidiosa-another xylem-limited Xanthomonadaceae. The present manuscript on the same genome sequence aims to describe all other pathogenicity-related genomic features of X. albilineans, and to compare, using suppression subtractive hybridization (SSH), genomic features of two strains differing in pathogenicity. RESULTS Comparative genomic analyses showed that most of the known pathogenicity factors from other Xanthomonas species are conserved in X. albilineans, with the notable absence of two major determinants of the "artillery" of other plant pathogenic species of Xanthomonas: the xanthan gum biosynthesis gene cluster, and the type III secretion system Hrp (hypersensitive response and pathogenicity). Genomic features specific to X. albilineans that may contribute to specific adaptation of this pathogen to sugarcane xylem vessels were also revealed. SSH experiments led to the identification of 20 genes common to three highly pathogenic strains but missing in a less pathogenic strain. These 20 genes, which include four ABC transporter genes, a methyl-accepting chemotaxis protein gene and an oxidoreductase gene, could play a key role in pathogenicity. With the exception of hypothetical proteins revealed by our comparative genomic analyses and SSH experiments, no genes potentially involved in any offensive or counter-defensive mechanism specific to X. albilineans were identified, supposing that X. albilineans has a reduced artillery compared to other pathogenic Xanthomonas species. Particular attention has therefore been given to genomic features specific to X. albilineans making it more capable of evading sugarcane surveillance systems or resisting sugarcane defense systems. CONCLUSIONS This study confirms that X. albilineans is a highly distinctive species within the genus Xanthomonas, and opens new perpectives towards a greater understanding of the pathogenicity of this destructive sugarcane pathogen.
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Affiliation(s)
| | - Monique Royer
- CIRAD, UMR BGPI, F-34398 Montpellier Cedex 5, France
| | - Valérie Barbe
- CEA/DSV/IG/Génoscope, Centre National de Séquençage, F-91057 Evry Cedex France
| | | | - Ralf Koebnik
- IRD, UMR RPB, F-34394 Montpellier Cedex 5, France
| | - Arnaud Couloux
- CEA/DSV/IG/Génoscope, Centre National de Séquençage, F-91057 Evry Cedex France
| | | | - Jérôme Gouzy
- INRA, UMR LIPM, F-31326 Castanet-Tolosan Cedex France
| | | | | | | | - Sophie Mangenot
- CEA/DSV/IG/Génoscope, Centre National de Séquençage, F-91057 Evry Cedex France
| | - Stéphane Poussier
- Université de la Réunion, UMR PVBMT, F-97715 Saint-Denis La Réunion, France
| | - Béatrice Segurens
- CEA/DSV/IG/Génoscope, Centre National de Séquençage, F-91057 Evry Cedex France
| | - Boris Szurek
- IRD, UMR RPB, F-34394 Montpellier Cedex 5, France
| | | | - Matthieu Arlat
- Université Paul Sabatier, UMR LIPM, F-31326 Castanet-Tolosan Cedex France
| | - Dean W Gabriel
- University of Florida, Plant Pathology Department, Gainesville FL 32605 USA
| | - Philippe Rott
- CIRAD, UMR BGPI, F-34398 Montpellier Cedex 5, France
| | - Stéphane Cociancich
- CIRAD, UMR BGPI, F-34398 Montpellier Cedex 5, France
- UMR BGPI, Campus International de Baillarguet, TA A-54/K, F-34398 Montpellier Cedex 5, France
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Qian G, Zhang Y, Zhou Y, Liu C, Zhao Y, Song Z, Fan J, Hu B, Liu F. epv, Encoding a hypothetical protein, is regulated by DSF-mediating quorum sensing as well as global regulator Clp and is required for optimal virulence in Xanthomonas oryzae pv. oryzicola. PHYTOPATHOLOGY 2012; 102:841-7. [PMID: 22881870 DOI: 10.1094/phyto-02-12-0020-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Xanthomonas oryzae pv. oryzicola causes bacterial leaf streak in rice, a destructive disease worldwide. In this study, six putative hypothetical secreted proteins, which were absent in X. oryzae pv. oryzae, were detected from X. oryzae pv. oryzicola strain BLS256. Disruption-based mutagenesis study revealed that one of them, Xoc_15235, named as extracellular polysaccharide and virulence-related gene (epv), was required for the optimal virulence in host rice but not for the induction of a hypersensitive reaction in nonhost tobacco. Sequence analysis revealed that epv was highly conserved in Xanthomonas spp. (except X. oryzae pv. oryzae). In-frame deletion of epv in X. oryzae pv. oryzicola dramatically impaired pathogen virulence and extracellular polysaccharide (EPS) production, one of the important known virulence-associated functions in Xanthomonas spp. Quantitative real-time reverse-transcription polymerase chain reaction showed that expression of both gumB (a gene encoding exopolysaccharide xanthan biosynthesis export protein) and a known virulence-related gene, pgk (encoding phosphoglycerate kinase), were obviously reduced in the epv-deletion mutant compared with the wild-type strain Rs105. In addition, we observed that epv was positively regulated by both diffusible signal factor and global regulator Clp in X. oryzae pv. oryzicola. Taken together, the novel roles and genetics of epv of X. oryzae pv. oryzicola in the EPS production and virulence were investigated for the first time.
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Affiliation(s)
- Guoliang Qian
- College of Plant Protection and Key Laboratory of Integrated Management of Corp Diseases and Pests, Ministry of Education, Nanjing Agricultural University, China
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Subramoni S, Pandey A, Vishnu Priya MR, Patel HK, Sonti RV. The ColRS system of Xanthomonas oryzae pv. oryzae is required for virulence and growth in iron-limiting conditions. MOLECULAR PLANT PATHOLOGY 2012; 13:690-703. [PMID: 22257308 PMCID: PMC6638901 DOI: 10.1111/j.1364-3703.2011.00777.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: 05/09/2023]
Abstract
Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice, produces siderophores only under iron-limiting conditions. We screened 15 400 mTn5-induced mutants of X. oryzae pv. oryzae and isolated 27 mutants that produced siderophores even under iron-replete conditions. We found that the mTn5 insertions in 25 of these mutants were in or close to six genes. Mutants with insertions in five of these genes [colS, XOO1806 (a conserved hypothetical protein), acnB, prpR and prpB] exhibited a deficiency for growth on iron-limiting medium and a decrease in virulence. Insertions in a sixth gene, XOO0007 (a conserved hypothetical protein), were found to affect the ability to grow on iron-limiting medium, but did not affect the virulence. Targeted gene disruptants for colR (encoding the predicted cognate regulatory protein for ColS) also exhibited a deficiency for growth on iron-limiting medium and a decrease in virulence. colR and colS mutants were defective in the elicitation of hypersensitive response symptoms on the nonhost tomato. In addition, colR and colS mutants induced a rice basal defence response, suggesting that they are compromised in the suppression of host innate immunity. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis demonstrated that a functional ColRS system is required for the optimal expression of several genes encoding components of the type 3 secretion system (T3SS) of X. oryzae pv. oryzae. Our results demonstrate the role of several novel genes, including colR/colS, in the promotion of growth on iron-limiting medium and the virulence of X. oryzae pv. oryzae.
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Affiliation(s)
- Sujatha Subramoni
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad-500 007, Andhra Pradesh, India
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Zhao Y, Qian G, Fan J, Yin F, Zhou Y, Liu C, Shen Q, Hu B, Liu F. Identification and characterization of a novel gene, hshB, in Xanthomonas oryzae pv. oryzicola co-regulated by quorum sensing and clp. PHYTOPATHOLOGY 2012; 102:252-259. [PMID: 22106829 DOI: 10.1094/phyto-06-11-0169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Virulence factors of Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in rice, are regulated by a diffusible signal factor (DSF)-dependent quorum-sensing (QS) system. In this study, a novel pathogenicity-related gene, Xoryp_010100018570 (named hshB), of X. oryzae pv. oryzicola was characterized. hshB encodes a hydrolase with a putative signal peptide, which is a homolog of imidazolonepropionase. Bioinformatic analysis showed that hshB is relatively conserved in the genus Xanthomonas but the homologous gene of hshB was not found in X. oryzae pv. oryzae. Reverse-transcription polymerase chain reaction (PCR) analysis showed that hshB and its upstream gene, Xoryp_010100018565 (named hshA), are co-transcribed in X. oryzae pv. oryzicola. Subsequent experimental results indicated that mutation of hshB remarkably impaired the virulence, extracellular protease activity, extracellular polysaccharide production, growth in minimal medium, and resistance to oxidative stress and bismerthiazol of X. oryzae pv. oryzicola. Mutation of clp, encoding a global regulator, resulted in similar phenotypes. Real-time PCR assays showed that hshB transcription is positively regulated by clp and DSF, and induced by poor nutrition. Our study not only found a novel gene hshB regulated by DSF-dependent QS system and clp but also showed that hshB was required for virulence of X. oryzae pv. oryzicola.
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Affiliation(s)
- Yancun Zhao
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Disease and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
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Guo W, Zou LF, Li YR, Cui YP, Ji ZY, Cai LL, Zou HS, Hutchins WC, Yang CH, Chen GY. Fructose-bisphophate aldolase exhibits functional roles between carbon metabolism and the hrp system in rice pathogen Xanthomonas oryzae pv. oryzicola. PLoS One 2012; 7:e31855. [PMID: 22384086 PMCID: PMC3285194 DOI: 10.1371/journal.pone.0031855] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Accepted: 01/17/2012] [Indexed: 02/01/2023] Open
Abstract
Fructose-bisphophate aldolase (FbaB), is an enzyme in glycolysis and gluconeogenesis in living organisms. The mutagenesis in a unique fbaB gene of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak, led the pathogen not only unable to use pyruvate and malate for growth and delayed its growth when fructose was used as the sole carbon source, but also reduced extracellular polysaccharide (EPS) production and impaired bacterial virulence and growth in rice. Intriguingly, the fbaB promoter contains an imperfect PIP-box (plant-inducible promoter) (TTCGT-N9-TTCGT). The expression of fbaB was negatively regulated by a key hrp regulatory HrpG and HrpX cascade. Base substitution in the PIP-box altered the regulation of fbaB with the cascade. Furthermore, the expression of fbaB in X. oryzae pv. oryzicola RS105 strain was inducible in planta rather than in a nutrient-rich medium. Except other hrp-hrc-hpa genes, the expression of hrpG and hrpX was repressed and the transcripts of hrcC, hrpE and hpa3 were enhanced when fbaB was deleted. The mutation in hrcC, hrpE or hpa3 reduced the ability of the pathogen to acquire pyruvate and malate. In addition, bacterial virulence and growth in planta and EPS production in RΔfbaB mutant were completely restored to the wild-type level by the presence of fbaB in trans. This is the first report to demonstrate that carbohydrates, assimilated by X. oryzae pv. oryzicola, play critical roles in coordinating hrp gene expression through a yet unknown regulator.
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Affiliation(s)
- Wei Guo
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education of China, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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Han SW, Sriariyanun M, Lee SW, Sharma M, Bahar O, Bower Z, Ronald PC. Small protein-mediated quorum sensing in a Gram-negative bacterium. PLoS One 2011; 6:e29192. [PMID: 22174954 PMCID: PMC3236232 DOI: 10.1371/journal.pone.0029192] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 11/22/2011] [Indexed: 12/02/2022] Open
Abstract
The rice XA21 pattern recognition receptor binds a type I secreted sulfated peptide, called axYS22, derived from the Ax21 (activator of XA21-mediated immunity) protein. The conservation of Ax21 in all sequenced Xanthomonas spp. and closely related genera suggests that Ax21 serves a key biological function. Here we show that the predicted N-terminal sequence of Ax21 is cleaved prior to secretion outside the cell and that mature Ax21 serves as a quorum sensing (QS) factor in Xanthomonas oryzae pv. oryzae. Ax21-mediated QS controls motility, biofilm formation and virulence. We provide genetic evidence that the Xoo RaxH histidine kinase serves as the bacterial receptor for Ax21. This work establishes a critical role for small protein-mediated QS in a Gram-negative bacterium.
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Affiliation(s)
- Sang-Wook Han
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
| | - Malinee Sriariyanun
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
| | - Sang-Won Lee
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
- The Department of Plant Molecular System Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
| | - Manoj Sharma
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
| | - Ofir Bahar
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
| | - Zachary Bower
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
| | - Pamela C. Ronald
- Department of Plant Pathology and the Genome Center, University of California Davis, Davis, California, United States of America
- The Department of Plant Molecular System Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
- * E-mail:
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