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Huang J, Wang R, Zhang Q, Wang C, Liang T, Hikichi Y, Ohnishi K, Jiang G, Guo T, Zhang Y. Positive regulation of the PhcB neighbouring regulator PrhX on expression of the type III secretion system and pathogenesis in Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2024; 25:e13398. [PMID: 37877898 PMCID: PMC10788593 DOI: 10.1111/mpp.13398] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/04/2023] [Accepted: 10/04/2023] [Indexed: 10/26/2023]
Abstract
Ralstonia solanacearum PhcB and PhcA control a quorum-sensing (QS) system that globally regulates expression of about one third of all genes, including pathogenesis genes. The PhcB-PhcA QS system positively regulates the production of exopolysaccharide (EPS) and negatively regulates hrp gene expression, which is crucial for the type III secretion system (T3SS). Both EPS and the T3SS are essential for pathogenicity. The gene rsc2734 is located upstream of a phcBSR operon and annotated as a response regulator of a two-component system. Here, we demonstrated that RSc2734, hereafter named PrhX, positively regulated hrp gene expression via a PrhA-PrhIR-PrhJ-HrpG signalling cascade. Moreover, PrhX was crucial for R. solanacearum to invade host roots and grow in planta naturally. prhX expression was independent of the PhcB-PhcA QS system. PrhX did not affect the expression of phcB and phcA and the QS-dependent phenotypes, such as EPS production and biofilm formation. Our results provide novel insights into the complex regulatory network of the T3SS and pathogenesis in R. solanacearum.
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Affiliation(s)
- Jiajun Huang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Rongsheng Wang
- Liaoning Key Laboratory of Plant Pathology, College of Plant ProtectionShenyang Agricultural UniversityShenyangChina
| | - Qi Zhang
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Chunli Wang
- Chongqing Academy of Agricultural SciencesChongqingChina
| | - Tao Liang
- Chongqing Station of Agricultural Ecology and Resource ProtectionChongqingChina
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Gaofei Jiang
- National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityNanjingChina
| | - Tao Guo
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River BasinSouthwest UniversityChongqingChina
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2
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Franklin TG, Brzovic PS, Pruneda JN. Bacterial ligases reveal fundamental principles of polyubiquitin specificity. Mol Cell 2023; 83:4538-4554.e4. [PMID: 38091999 PMCID: PMC10872931 DOI: 10.1016/j.molcel.2023.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/28/2023] [Accepted: 11/15/2023] [Indexed: 12/24/2023]
Abstract
Homologous to E6AP C terminus (HECT) E3 ubiquitin (Ub) ligases direct substrates toward distinct cellular fates dictated by the specific form of monomeric or polymeric Ub (polyUb) signal attached. How polyUb specificity is achieved has been a long-standing mystery, despite extensive study in various hosts, ranging from yeast to human. The bacterial pathogens enterohemorrhagic Escherichia coli and Salmonella Typhimurium encode outlying examples of "HECT-like" (bHECT) E3 ligases, but commonalities to eukaryotic HECT (eHECT) mechanism and specificity had not been explored. We expanded the bHECT family with examples in human and plant pathogens. Three bHECT structures in primed, Ub-loaded states resolved key details of the entire Ub ligation process. One structure provided a rare glimpse into the act of ligating polyUb, yielding a means to rewire polyUb specificity of both bHECT and eHECT ligases. Studying this evolutionarily distinct bHECT family has revealed insight into the function of key bacterial virulence factors as well as fundamental principles underlying HECT-type Ub ligation.
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Affiliation(s)
- Tyler G Franklin
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Peter S Brzovic
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jonathan N Pruneda
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA.
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3
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Liu S, Xue Q, Zhu S, Liu Y, Zou H. Ralstonia solanacearum Suppresses Tomato Root Growth by Downregulation of a Wall-Associated Receptor Kinase. PLANTS (BASEL, SWITZERLAND) 2023; 12:3600. [PMID: 37896064 PMCID: PMC10610323 DOI: 10.3390/plants12203600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 10/06/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023]
Abstract
The root architecture of a range of host plants is altered in response to Ralstonia solanacearum infection. This work aimed to identify host genes involved in root development during R. solanacearum infection. A deficient mutant of the type III secretion system regulator hrpB was created in R. solanacearum GMI1000. The hrpB mutant was impaired in virulence but showed a similar suppressive effect as wild-type GMI1000 on tomato root development. Based on comparative transcriptome analysis, 209 genes were found that showed the same changed expression pattern in GMI1000 and hrpB mutant infected roots relative to uninoculated roots. Among them, the wall-associated receptor kinase WAKL20 was substantially downregulated in GMI1000 and hrpB mutant infected roots. Knockdown of WAKL20 led to a shorter primary root length and fewer lateral roots in tomato as well as in Nicotiana benthamiana. The WAKL20 is a pivotal target suppressed by R. solanacearum to shape the altered root development during infection.
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Affiliation(s)
| | | | | | | | - Huasong Zou
- School of Life Sciences and Health, Huzhou College, Huzhou 313000, China; (S.L.); (Q.X.); (S.Z.); (Y.L.)
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4
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Kim B, Kim I, Yu W, Li M, Kim H, Ahn YJ, Sohn KH, Macho AP, Segonzac C. The Ralstonia pseudosolanacearum effector RipE1 is recognized at the plasma membrane by NbPtr1, the Nicotiana benthamiana homologue of Pseudomonas tomato race 1. MOLECULAR PLANT PATHOLOGY 2023; 24:1312-1318. [PMID: 37310613 PMCID: PMC10502825 DOI: 10.1111/mpp.13363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/07/2023] [Accepted: 05/22/2023] [Indexed: 06/14/2023]
Abstract
The bacterial wilt disease caused by soilborne bacteria of the Ralstonia solanacearum species complex (RSSC) threatens important crops worldwide. Only a few immune receptors conferring resistance to this devastating disease are known so far. Individual RSSC strains deliver around 70 different type III secretion system effectors into host cells to manipulate the plant physiology. RipE1 is an effector conserved across the RSSC and triggers immune responses in the model solanaceous plant Nicotiana benthamiana. Here, we used multiplexed virus-induced gene silencing of the nucleotide-binding and leucine-rich repeat receptor family to identify the genetic basis of RipE1 recognition. Specific silencing of the N. benthamiana homologue of Solanum lycopersicoides Ptr1 (confers resistance to Pseudomonas syringae pv. tomato race 1) gene (NbPtr1) completely abolished RipE1-induced hypersensitive response and immunity to Ralstonia pseudosolanacearum. The expression of the native NbPtr1 coding sequence was sufficient to restore RipE1 recognition in Nb-ptr1 knockout plants. Interestingly, RipE1 association with the host cell plasma membrane was necessary for NbPtr1-dependent recognition. Furthermore, NbPtr1-dependent recognition of RipE1 natural variants is polymorphic, providing additional evidence for the indirect mode of activation of NbPtr1. Altogether, this work supports NbPtr1 relevance for resistance to bacterial wilt disease in Solanaceae.
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Affiliation(s)
- Boyoung Kim
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Injae Kim
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Wenjia Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Meng Li
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Haseong Kim
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Ye Jin Ahn
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Kee Hoon Sohn
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
- Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulRepublic of Korea
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Cécile Segonzac
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
- Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulRepublic of Korea
- Plant Genomics and Breeding InstituteSeoul National UniversitySeoulRepublic of Korea
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Roberts CG, Franklin TG, Pruneda JN. Ubiquitin-targeted bacterial effectors: rule breakers of the ubiquitin system. EMBO J 2023; 42:e114318. [PMID: 37555693 PMCID: PMC10505922 DOI: 10.15252/embj.2023114318] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/10/2023] [Accepted: 07/18/2023] [Indexed: 08/10/2023] Open
Abstract
Regulation through post-translational ubiquitin signaling underlies a large portion of eukaryotic biology. This has not gone unnoticed by invading pathogens, many of which have evolved mechanisms to manipulate or subvert the host ubiquitin system. Bacteria are particularly adept at this and rely heavily upon ubiquitin-targeted virulence factors for invasion and replication. Despite lacking a conventional ubiquitin system of their own, many bacterial ubiquitin regulators loosely follow the structural and mechanistic rules established by eukaryotic ubiquitin machinery. Others completely break these rules and have evolved novel structural folds, exhibit distinct mechanisms of regulation, or catalyze foreign ubiquitin modifications. Studying these interactions can not only reveal important aspects of bacterial pathogenesis but also shed light on unexplored areas of ubiquitin signaling and regulation. In this review, we discuss the methods by which bacteria manipulate host ubiquitin and highlight aspects that follow or break the rules of ubiquitination.
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Affiliation(s)
- Cameron G Roberts
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
| | - Tyler G Franklin
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
| | - Jonathan N Pruneda
- Department of Molecular Microbiology & ImmunologyOregon Health & Science UniversityPortlandORUSA
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Qiu H, Wang B, Huang M, Sun X, Yu L, Cheng D, He W, Zhou D, Wu X, Song B, Tang N, Chen H. A novel effector RipBT contributes to Ralstonia solanacearum virulence on potato. MOLECULAR PLANT PATHOLOGY 2023; 24:947-960. [PMID: 37154802 PMCID: PMC10346376 DOI: 10.1111/mpp.13342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 03/21/2023] [Accepted: 04/05/2023] [Indexed: 05/10/2023]
Abstract
Ralstonia solanacearum is one of the most destructive plant-pathogenic bacteria, infecting more than 200 plant species, including potato (Solanum tuberosum) and many other solanaceous crops. R. solanacearum has numerous pathogenicity factors, and type III effectors secreted through type III secretion system (T3SS) are key factors to counteract host immunity. Here, we show that RipBT is a novel T3SS-secreted effector by using a cyaA reporter system. Transient expression of RipBT in Nicotiania benthamiana induced strong cell death in a plasma membrane-localization dependent manner. Notably, mutation of RipBT in R. solanacearum showed attenuated virulence on potato, while RipBT transgenic potato plants exhibited enhanced susceptibility to R. solanacearum. Interestingly, transcriptomic analyses suggest that RipBT may interfere with plant reactive oxygen species (ROS) metabolism during the R. solanacearum infection of potato roots. In addition, the expression of RipBT remarkably suppressed the flg22-induced pathogen-associated molecular pattern-triggered immunity responses, such as the ROS burst. Taken together, RipBT acts as a T3SS effector, promoting R. solanacearum infection on potato and presumably disturbing ROS homeostasis.
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Affiliation(s)
- Huishan Qiu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Bingsen Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Mengshu Huang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Xiaohu Sun
- State Key Laboratory of Crop Stress Adaptation and ImprovementHenan UniversityKaifengChina
| | - Liu Yu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Dong Cheng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Wenfeng He
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Dan Zhou
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Xintong Wu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Botao Song
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
| | - Ning Tang
- State Key Laboratory of Crop Stress Adaptation and ImprovementHenan UniversityKaifengChina
| | - Huilan Chen
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural CropsHuazhong Agricultural UniversityWuhanChina
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhanChina
- Potato Engineering and Technology Research Center of Hubei ProvinceHuazhong Agricultural UniversityWuhanChina
- College of Horticulture and Forestry ScienceHuazhong Agricultural UniversityWuhanChina
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7
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Franklin TG, Brzovic PS, Pruneda JN. Bacterial mimicry of eukaryotic HECT ubiquitin ligation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543783. [PMID: 37333152 PMCID: PMC10274628 DOI: 10.1101/2023.06.05.543783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
HECT E3 ubiquitin (Ub) ligases direct their modified substrates toward a range of cellular fates dictated by the specific form of monomeric or polymeric Ub (polyUb) signal that is attached. How polyUb specificity is achieved has been a longstanding mystery, despite extensive study ranging from yeast to human. Two outlying examples of bacterial "HECT-like" (bHECT) E3 ligases have been reported in the human pathogens Enterohemorrhagic Escherichia coli and Salmonella Typhimurium, but what parallels can be drawn to eukaryotic HECT (eHECT) mechanism and specificity had not been explored. Here, we expanded the bHECT family and identified catalytically active, bona fide examples in both human and plant pathogens. By determining structures for three bHECT complexes in their primed, Ub-loaded states, we resolved key details of the full bHECT Ub ligation mechanism. One structure provided the first glimpse of a HECT E3 ligase in the act of ligating polyUb, yielding a means to rewire the polyUb specificity of both bHECT and eHECT ligases. Through studying this evolutionarily distinct bHECT family, we have not only gained insight into the function of key bacterial virulence factors but also revealed fundamental principles underlying HECT-type Ub ligation.
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Affiliation(s)
- Tyler G. Franklin
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Peter S. Brzovic
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jonathan N. Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
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8
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Cong S, Li JZ, Xiong ZZ, Wei HL. Diverse interactions of five core type III effectors from Ralstonia solanacearum with plants. J Genet Genomics 2023; 50:341-352. [PMID: 35597445 DOI: 10.1016/j.jgg.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 11/24/2022]
Abstract
Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type III effectors (T3Es) to cause disease. In this study, we isolate a pathogenic R. solanacearum strain named P380 from tomato rhizosphere. Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants. DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression, ROS burst, and callose deposition. RipAE, RipU, and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana. The derivatives RipC1ΔDXDX(T/V) and RipWΔDKXXQ but not RipAEK310R fail to suppress ROS burst. Moreover, RipAEK310R and RipWΔDKXXQ retain the cell death elicitation ability. RipAE and RipW are associated with salicylic acid and jasmonic acid pathways, respectively. RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants. The five core T3Es localize in diverse subcellular organelles of nucleus, plasma membrane, endoplasmic reticulum, and Golgi network. The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N. benthamiana. These results indicate that the core T3Es in R. solanacearum play diverse roles in plant-pathogen interactions.
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Affiliation(s)
- Shen Cong
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jun-Zhou Li
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zheng-Zhong Xiong
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Hai-Lei Wei
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Huang M, Tan X, Song B, Wang Y, Cheng D, Wang B, Chen H. Comparative genomic analysis of Ralstonia solanacearum reveals candidate avirulence effectors in HA4-1 triggering wild potato immunity. FRONTIERS IN PLANT SCIENCE 2023; 14:1075042. [PMID: 36909411 PMCID: PMC9997847 DOI: 10.3389/fpls.2023.1075042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Ralstonia solanacearum is the causal agent of potato bacterial wilt, a major potato bacterial disease. Among the pathogenicity determinants, the Type III Secretion System Effectors (T3Es) play a vital role in the interaction. Investigating the avirulent T3Es recognized by host resistance proteins is an effective method to uncover the resistance mechanism of potato against R. solanacearum. Two closely related R. solanacearum strains HA4-1 and HZAU091 were found to be avirulent and highly virulent to the wild potato Solanum albicans 28-1, respectively. The complete genome of HZAU091 was sequenced in this study. HZAU091 and HA4-1 shared over 99.9% nucleotide identity with each other. Comparing genomics of closely related strains provides deeper insights into the interaction between hosts and pathogens, especially the mechanism of virulence. The comparison of type III effector repertoires between HA4-1 and HZAU091 uncovered seven distinct effectors. Two predicted effectors RipA5 and the novel effector RipBS in HA4-1 could significantly reduce the virulence of HZAU091 when they were transformed into HZAU091. Furthermore, the pathogenicity assays of mutated strains HA4-1 ΔRipS6, HA4-1 ΔRipO1, HA4-1 ΔRipBS, and HA4-1 ΔHyp6 uncovered that the absence of these T3Es enhanced the HA4-1 virulence to wild potato S. albicans 28-1. This result indicated that these T3Es may be recognized by S. albicans 28-1 as avirulence proteins to trigger the resistance. In summary, this study provides a foundation to unravel the R. solanacearum-potato interaction and facilitates the development of resistance potato against bacterial wilt.
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Affiliation(s)
- Mengshu Huang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaodan Tan
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
- Guangdong University Key Laboratory for Sustainable Control of Fruit and Vegetable Diseases and Pests & Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China, Ministry of Agriculture and Rural Affairs, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Botao Song
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yuqi Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dong Cheng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Bingsen Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Huilan Chen
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
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10
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De Ryck J, Van Damme P, Goormachtig S. From prediction to function: Current practices and challenges towards the functional characterization of type III effectors. Front Microbiol 2023; 14:1113442. [PMID: 36846751 PMCID: PMC9945535 DOI: 10.3389/fmicb.2023.1113442] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/19/2023] [Indexed: 02/10/2023] Open
Abstract
The type III secretion system (T3SS) is a well-studied pathogenicity determinant of many bacteria through which effectors (T3Es) are translocated into the host cell, where they exercise a wide range of functions to deceive the host cell's immunity and to establish a niche. Here we look at the different approaches that are used to functionally characterize a T3E. Such approaches include host localization studies, virulence screenings, biochemical activity assays, and large-scale omics, such as transcriptomics, interactomics, and metabolomics, among others. By means of the phytopathogenic Ralstonia solanacearum species complex (RSSC) as a case study, the current advances of these methods will be explored, alongside the progress made in understanding effector biology. Data obtained by such complementary methods provide crucial information to comprehend the entire function of the effectome and will eventually lead to a better understanding of the phytopathogen, opening opportunities to tackle it.
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Affiliation(s)
- Joren De Ryck
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium,Center for Plant Systems Biology, VIB, Ghent, Belgium,iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Petra Van Damme
- iRIP Unit, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Sofie Goormachtig
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium,Center for Plant Systems Biology, VIB, Ghent, Belgium,*Correspondence: Sofie Goormachtig,
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11
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Zhang Q, Wu B, Han L, Yu D, Liang T, Wang Y, Guo T. Functional characterization of two 3-dehydroquinases of AroQ1 and AroQ2 in the shikimate pathway and expression of genes for the type III secretion system in Ralstonia solanacearum. Front Microbiol 2023; 14:1186688. [PMID: 37180250 PMCID: PMC10171560 DOI: 10.3389/fmicb.2023.1186688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/28/2023] [Indexed: 05/16/2023] Open
Abstract
The shikimate pathway is a general route for the biosynthesis of aromatic amino acids (AAAs) in many microorganisms. A 3-dehydroquinase, AroQ, controls the third step of the shikimate pathway that catalyzes the formation of 3-dehydroquinate from 3-dehydroshikimate via a trans-dehydration reaction. Ralstonia solanacearum harbors two 3-dehydroquinases, AroQ1 and AroQ2, sharing 52% similarity in amino acids. Here, we demonstrated that two 3-dehydroquinases, AroQ1 and AroQ2, are essential for the shikimate pathway in R. solanacearum. The growth of R. solanacearum was completely diminished in a nutriment-limited medium with the deletion of both aroQ1 and aroQ2, while substantially impaired in planta. The aroQ1/2 double mutant was able to replicate in planta but grew slowly, which was ~4 orders of magnitude less than the parent strain to proliferate to the maximum cell densities in tomato xylem vessels. Moreover, the aroQ1/2 double mutant failed to cause disease in tomato and tobacco plants, whereas the deletion of either aroQ1 or aroQ2 did not alter the growth of R. solanacearum or pathogenicity on host plants. Supplementary shikimic acid (SA), an important intermediate of the shikimate pathway, substantially restored the diminished or impaired growth of aroQ1/2 double mutant in a limited medium or inside host plants. The necessity of AroQ1 and AroQ2 on the pathogenicity of solanacearum toward host plants was partially due to insufficient SA inside host plants. Moreover, the deletion of both aroQ1 and aroQ2 significantly impaired the expression of genes for the type III secretion system (T3SS) both in vitro and in planta. Its involvement in the T3SS was mediated through the well-characterized PrhA signaling cascade and was independent of growth deficiency under nutrient-limited conditions. Taken together, R. solanacearum 3-dehydroquinases play important roles in bacterial growth, the expression of the T3SS, and pathogenicity in host plants. These results could extend our insights into the understanding of the biological function of AroQ and the sophisticated regulation of the T3SS in R. solanacearum.
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Affiliation(s)
- Qingshan Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Bofan Wu
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Duan Yu
- Chongqing Academy of Agricultural Sciences, Chongqing, China
| | - Tao Liang
- Chongqing Academy of Agricultural Sciences, Chongqing, China
| | - Yan Wang
- Chongqing Academy of Agricultural Sciences, Chongqing, China
- *Correspondence: Yan Wang
| | - Tao Guo
- College of Resources and Environment, Southwest University, Chongqing, China
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12
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Rivera-Zuluaga K, Hiles R, Barua P, Caldwell D, Iyer-Pascuzzi AS. Getting to the root of Ralstonia invasion. Semin Cell Dev Biol 2022; 148-149:3-12. [PMID: 36526528 DOI: 10.1016/j.semcdb.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/16/2022]
Abstract
Plant diseases caused by soilborne pathogens are a major limiting factor in crop production. Bacterial wilt disease, caused by soilborne bacteria in the Ralstonia solanacearum Species Complex (Ralstonia), results in significant crop loss throughout the world. Ralstonia invades root systems and colonizes plant xylem, changing plant physiology and ultimately causing plant wilting in susceptible varieties. Elucidating how Ralstonia invades and colonizes plants is central to developing strategies for crop protection. Here we review Ralstonia pathogenesis from root detection and attachment, early root colonization, xylem invasion and subsequent wilting. We focus primarily on studies in tomato from the last 5-10 years. Recent work has identified elegant mechanisms Ralstonia uses to adapt to the plant xylem, and has discovered new genes that function in Ralstonia fitness in planta. A picture is emerging of an amazingly versatile pathogen that uses multiple strategies to make its surrounding environment more hospitable and can adapt to new environments.
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13
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Guan Y, Wang R, Chen N, Zhu Y, Han L, Chen X, Li J, Zhang Y. Functional characterization of a gamma-glutamyl phosphate reductase ProA in proline biosynthesis and promoting expression of type three secretion system in Ralstonia solanacearum. Front Microbiol 2022; 13:945831. [PMID: 36106083 PMCID: PMC9465252 DOI: 10.3389/fmicb.2022.945831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/05/2022] [Indexed: 11/24/2022] Open
Abstract
Ralstonia solanacearum RSc2741 has been predicted as a gamma-glutamyl phosphate reductase ProA catalyzing the second reaction of proline formation from glutamate. Here, we experimentally demonstrated that proA mutants were proline auxotrophs that failed to grow in a minimal medium, and supplementary proline, but not glutamate, fully restored the diminished growth, confirming that ProA is responsible for the biosynthesis of proline from glutamate in R. solanacearum. ProA was previously identified as one of the candidates regulating the expression of genes for type three secretion system (T3SS), one of the essential pathogenicity determinants of R. solanacearum. Supplementary proline significantly enhanced the T3SS expression both in vitro and in planta, indicating that proline is a novel inducer of the T3SS expression. Deletion of proA substantially impaired the T3SS expression both in vitro and in planta even under proline-supplemented conditions, indicating that ProA plays additional roles apart from proline biosynthesis in promoting the expression of the T3SS genes. It was further revealed that the involvement of ProA in the T3SS expression was mediated through the pathway of PrhG-HrpB. Both the proA mutants and the wild-type strain grew in the intercellular spaces of tobacco leaves, while their ability to invade and colonize tobacco xylem vessels was substantially impaired, which was about a 1-day delay for proA mutants to successfully invade xylem vessels and was about one order of magnitude less than the wild-type strain to proliferate to the maximum densities in xylem vessels. It thus resulted in substantially impaired virulence of proA mutants toward host tobacco plants. The impaired abilities of proA mutants to invade and colonize xylem vessels were not due to possible proline insufficiency in the rhizosphere soil or inside the plants. All taken together, these results extend novel insights into the understanding of the biological function of ProA and sophisticated regulation of the T3SS and pathogenicity in R. solanacearum.
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Affiliation(s)
- Yue Guan
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Rongsheng Wang
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Nan Chen
- College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Yalan Zhu
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Xinping Chen
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Jing Li
- The Ninth People’s Hospital of Chongqing, Chongqing, China
- *Correspondence: Jing Li,
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
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14
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Bullones-Bolaños A, Bernal-Bayard J, Ramos-Morales F. The NEL Family of Bacterial E3 Ubiquitin Ligases. Int J Mol Sci 2022; 23:7725. [PMID: 35887072 PMCID: PMC9320238 DOI: 10.3390/ijms23147725] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 12/16/2022] Open
Abstract
Some pathogenic or symbiotic Gram-negative bacteria can manipulate the ubiquitination system of the eukaryotic host cell using a variety of strategies. Members of the genera Salmonella, Shigella, Sinorhizobium, and Ralstonia, among others, express E3 ubiquitin ligases that belong to the NEL family. These bacteria use type III secretion systems to translocate these proteins into host cells, where they will find their targets. In this review, we first introduce type III secretion systems and the ubiquitination process and consider the various ways bacteria use to alter the ubiquitin ligation machinery. We then focus on the members of the NEL family, their expression, translocation, and subcellular localization in the host cell, and we review what is known about the structure of these proteins, their function in virulence or symbiosis, and their specific targets.
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Affiliation(s)
| | | | - Francisco Ramos-Morales
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain; (A.B.-B.); (J.B.-B.)
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15
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Rosenthal E, Potnis N, Bull CT. Comparative Genomic Analysis of the Lettuce Bacterial Leaf Spot Pathogen, Xanthomonas hortorum pv. vitians, to Investigate Race Specificity. Front Microbiol 2022; 13:840311. [PMID: 35516433 PMCID: PMC9062649 DOI: 10.3389/fmicb.2022.840311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/09/2022] [Indexed: 01/01/2023] Open
Abstract
Bacterial leaf spot (BLS) of lettuce caused by Xanthomonas hortorum pv. vitians (Xhv) was first described over 100 years ago and remains a significant threat to lettuce cultivation today. This study investigated the genetic relatedness of the Xhv strains and the possible genetic sources of this race-specific pathogenicity. Whole genome sequences of eighteen Xhv strains representing the three races, along with eight related Xanthomonas strains, were included in the analysis. A maximum likelihood phylogeny based on concatenated whole genome SNPs confirmed previous results describing two major lineages of Xhv strains. Gene clusters encoding secretion systems, secondary metabolites, and bacteriocins were assessed to identify putative virulence factors that distinguish the Xhv races. Genome sequences were mined for effector genes, which have been shown to be involved in race specificity in other systems. Two effectors identified in this study, xopAQ and the novel variant xopAF2, were revealed as possible mediators of a gene-for-gene interaction between Xhv race 1 and 3 strains and wild lettuce Lactuca serriola ARM-09-161-10-1. Transposase sequence identified downstream of xopAF2 and prophage sequence found nearby within Xhv race 1 and 3 insertion sequences suggest that this gene may have been acquired through phage-mediated gene transfer. No other factors were identified from these analyses that distinguish the Xhv races.
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Affiliation(s)
- Emma Rosenthal
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, United States
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Carolee T Bull
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, United States
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16
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Chen M, Zhang W, Han L, Ru X, Cao Y, Hikichi Y, Ohnishi K, Pan G, Zhang Y. A CysB regulator positively regulates cysteine synthesis, expression of type III secretion system genes, and pathogenicity in Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2022; 23:679-692. [PMID: 35122373 PMCID: PMC8995062 DOI: 10.1111/mpp.13189] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 05/27/2023]
Abstract
A syringe-like type III secretion system (T3SS) plays essential roles in the pathogenicity of Ralstonia solanacearum, which is a causal agent of bacterial wilt disease on many plant species worldwide. Here, we characterized functional roles of a CysB regulator (RSc2427) in R. solanacearum OE1-1 that was demonstrated to be responsible for cysteine synthesis, expression of the T3SS genes, and pathogenicity of R. solanacearum. The cysB mutants were cysteine auxotrophs that failed to grow in minimal medium but grew slightly in host plants. Supplementary cysteine substantially restored the impaired growth of cysB mutants both in minimal medium and inside host plants. Genes of cysU and cysI regulons have been annotated to function for R. solanacearum cysteine synthesis; CysB positively regulated expression of these genes. Moreover, CysB positively regulated expression of the T3SS genes both in vitro and in planta through the PrhG to HrpB pathway, whilst impaired expression of the T3SS genes in cysB mutants was independent of growth deficiency under nutrient-limited conditions. CysB was also demonstrated to be required for exopolysaccharide production and swimming motility, which contribute jointly to the host colonization and infection process of R. solanacearum. Thus, CysB was identified here as a novel regulator on the T3SS expression in R. solanacearum. These results provide novel insights into understanding of various biological functions of CysB regulators and complex regulatory networks on the T3SS in R. solanacearum.
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Affiliation(s)
- Min Chen
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Weiqi Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Liangliang Han
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Xuejuan Ru
- Chongqing Academy of Agricultural SciencesChongqingChina
| | - Yuzhu Cao
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Guanghui Pan
- Chongqing Academy of Agricultural SciencesChongqingChina
| | - Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River BasinSouthwest UniversityChongqingChina
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17
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Du H, Yang J, Chen B, Zhang X, Xu X, Wen C, Geng S. Dual RNA-seq Reveals the Global Transcriptome Dynamics of Ralstonia solanacearum and Pepper ( Capsicum annuum) Hypocotyls During Bacterial Wilt Pathogenesis. PHYTOPATHOLOGY 2022; 112:630-642. [PMID: 34346759 DOI: 10.1094/phyto-01-21-0032-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bacterial wilt, caused by Ralstonia solanacearum, is a serious disease in pepper. However, the interaction between the pathogen and pepper remains largely unknown. This study aimed to gain insights into determinants of pepper susceptibility and R. solanacearum pathogenesis. We assembled the complete genome of R. solanacearum strain Rs-SY1 and identified 5,106 predicted genes, including 84 type III effectors (T3E). RNA-seq was used to identify differentially expressed genes (DEGs) in susceptible pepper CM334 at 1 and 5 days postinoculation (dpi) with R. solanacearum. Dual RNA-seq was used to simultaneously capture transcriptome changes in the host and pathogen at 3 and 7 dpi. A total of 1,400, 3,335, 2,878, and 4,484 DEGs of pepper (PDEGs) were identified in the CM334 hypocotyls at 1, 3, 5, and 7 dpi, respectively. Functional enrichment of the PDEGs suggests that inducing ethylene production, suppression of photosynthesis, downregulation of polysaccharide metabolism, and weakening of cell wall defenses may contribute to successful infection by R. solanacearum. When comparing in planta and nutrient agar growth of the R. solanacearum, 218 and 1,042 DEGs of R. solanacearum (RDEGs) were detected at 3 and 7 dpi, respectively. Additional analysis of the RDEGs suggested that enhanced starch and sucrose metabolism, and upregulation of virulence factors may promote R. solanacearum colonization. Strikingly, 26 R. solanacearum genes were found to have similar DEG patterns during a variety of host-R. solanacearum interactions. This study provides a foundation for a better understanding of the transcriptional changes during pepper-R. solanacearum interactions and will aid in the discovery of potential susceptibility and virulence factors.
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Affiliation(s)
- Heshan Du
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Jingjing Yang
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Bin Chen
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Xiaofen Zhang
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Xiulan Xu
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Changlong Wen
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Sansheng Geng
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
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18
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Recent Advancements in Tracking Bacterial Effector Protein Translocation. Microorganisms 2022; 10:microorganisms10020260. [PMID: 35208715 PMCID: PMC8876096 DOI: 10.3390/microorganisms10020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/17/2022] Open
Abstract
Bacteria-host interactions are characterized by the delivery of bacterial virulence factors, i.e., effectors, into host cells where they counteract host immunity and exploit host responses allowing bacterial survival and spreading. These effectors are translocated into host cells by means of dedicated secretion systems such as the type 3 secretion system (T3SS). A comprehensive understanding of effector translocation in a spatio-temporal manner is of critical importance to gain insights into an effector’s mode of action. Various approaches have been developed to understand timing and order of effector translocation, quantities of translocated effectors and their subcellular localization upon translocation into host cells. Recently, the existing toolset has been expanded by newly developed state-of-the art methods to monitor bacterial effector translocation and dynamics. In this review, we elaborate on reported methods and discuss recent advances and shortcomings in this area of tracking bacterial effector translocation.
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19
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Abstract
Various Gram-negative bacteria use secretion systems to secrete effector proteins that manipulate host biochemical pathways to their benefit. We and others have previously developed machine-learning algorithms to predict novel effectors. Specifically, given a set of known effectors and a set of known non-effectors, the machine-learning algorithm extracts features that distinguish these two protein groups. In the training phase, the machine learning learns how to best combine the features to separate the two groups. The trained machine learning is then applied to open reading frames (ORFs) with unknown functions, resulting in a score for each ORF, which is its likelihood to be an effector. We developed Effectidor, a web server for predicting type III effectors. In this book chapter, we provide a step-by-step introduction to the application of Effectidor, from selecting input data to analyzing the obtained predictions.
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Affiliation(s)
- Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv, Israel
| | - Doron Teper
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv, Israel.
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20
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Huh SU. PopP2 interacts with PAD4 in an acetyltransferase activity-dependent manner and affects plant immunity. PLANT SIGNALING & BEHAVIOR 2021; 16:2017631. [PMID: 34978271 PMCID: PMC9208800 DOI: 10.1080/15592324.2021.2017631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Plant pathogenic bacteria inject many of the effector proteins into host cell to manipulate host protein and promote pathogen development. Only a few effectors can be recognized by plant immune receptors called nucleotide-binding domain and leucine-rich repeat-containing proteins (NLRs). Enhanced disease susceptibility1 (EDS1) is an important regulator of plant basal and NLR receptor-triggered immunity. EDS1/PAD4 or EDS1/SAG101 heterodimers are recruited by Toll-interleukin1-receptor domain NLRs (TNLs) to transcriptionally mobilize resistance pathways. Type III effector PopP2 contributes to Ralstonia solanacearum virulence. PopP2 has an acetyltransferase activity and is recognized by Arabidopsis NLR pair RPS4/RRS1-R. On the other hand, PopP2 avirulence function is dependent on its enzymatic activity but target proteins in the host cell are still largely unknown. In this study, we found EDS1 and PAD4 are new host targets of PopP2 effector. Arabidopsis PAD4 lipase-like domain protein physically associates with enzymatic active PopP2 protein but not inactive PopP2C321A. PAD4-PopP2 interaction is disrupted by EDS1 immune regulator but not SAG101. We propose that acetyltransferase activity of PopP2 might confer specificity to PAD4 to manipulate plant immunity. As a counter strategy, EDS1 associates with PAD4 to form heterodimeric immune regulator complexes for activating basal resistance and interfering PopP2 physical interaction.
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Affiliation(s)
- Sung Un Huh
- Department of Biology, Kunsan National University, Gunsan, Republic of Korea
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21
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Laili N, Mukaihara T, Matsui H, Yamamoto M, Noutoshi Y, Toyoda K, Ichinose Y. Role of Trehalose Synthesis in Ralstonia syzygii subsp. indonesiensis PW1001 in Inducing Hypersensitive Response on Eggplant (Solanum melongena cv. Senryo-nigou). THE PLANT PATHOLOGY JOURNAL 2021; 37:566-579. [PMID: 34897249 PMCID: PMC8666247 DOI: 10.5423/ppj.oa.06.2021.0087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 06/14/2023]
Abstract
Ralstonia syzygii subsp. indonesiensis (Rsi, former name: Ralstonia solanacearum phylotype IV) PW1001, a causal agent of potato wilt disease, induces hypersensitive response (HR) on its non-host eggplant (Solanum melongena cv. Senryo-nigou). The disaccharide trehalose is involved in abiotic and biotic stress tolerance in many organisms. We found that trehalose is required for eliciting HR on eggplant by plant pathogen Rsi PW1001. In R. solanacearum, it is known that the OtsA/OtsB pathway is the dominant trehalose synthesis pathway, and otsA and otsB encode trehalose-6-phosphate (T6P) synthase and T6P phosphatase, respectively. We generated otsA and otsB mutant strains and found that these mutant strains reduced the bacterial trehalose concentration and HR induction on eggplant leaves compared to wild-type. Trehalose functions intracellularly in Rsi PW1001 because addition of exogenous trehalose did not affect the HR level and ion leakage. Requirement of trehalose in HR induction is not common in R. solanacearum species complex because mutation of otsA in Ralstonia pseudosolanacearum (former name: Ralstonia solanacearum phylotype I) RS1002 did not affect HR on the leaves of its non-host tobacco and wild eggplant Solanum torvum. Further, we also found that each otsA and otsB mutant had reduced ability to grow in a medium containing NaCl and sucrose, indicating that trehalose also has an important role in osmotic stress tolerance.
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Affiliation(s)
- Nur Laili
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
- Research Center for Biology, Research Organization for Life Sciences, National Research and Innovation Agency (BRIN), Jl. Raya Jakarta-Bogor Km. 46, Cibinong, Bogor, West Java 16911,
Indonesia
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241,
Japan
| | - Hidenori Matsui
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Mikihiro Yamamoto
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Yoshiteru Noutoshi
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Kazuhiro Toyoda
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Yuki Ichinose
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
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22
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Denne NL, Hiles RR, Kyrysyuk O, Iyer-Pascuzzi AS, Mitra RM. Ralstonia solanacearum Effectors Localize to Diverse Organelles in Solanum Hosts. PHYTOPATHOLOGY 2021; 111:2213-2226. [PMID: 33720750 DOI: 10.1094/phyto-10-20-0483-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Phytopathogenic bacteria secrete type III effector (T3E) proteins directly into host plant cells. T3Es can interact with plant proteins and frequently manipulate plant host physiological or developmental processes. The proper subcellular localization of T3Es is critical for their ability to interact with plant targets, and knowledge of T3E localization can be informative for studies of effector function. Here we investigated the subcellular localization of 19 T3Es from the phytopathogenic bacteria Ralstonia pseudosolanacearum and Ralstonia solanacearum. Approximately 45% of effectors in our library localize to both the plant cell periphery and the nucleus, 15% exclusively to the cell periphery, 15% exclusively to the nucleus, and 25% to other organelles, including tonoplasts and peroxisomes. Using tomato hairy roots, we show that T3E localization is similar in both leaves and roots and is not impacted by Solanum species. We find that in silico prediction programs are frequently inaccurate, highlighting the value of in planta localization experiments. Our data suggest that Ralstonia targets a wide diversity of cellular organelles and provides a foundation for developing testable hypotheses about Ralstonia effector function.
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Affiliation(s)
- Nina L Denne
- Department of Biology, Carleton College, Northfield, MN 55057
| | - Rachel R Hiles
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, IN 47907
| | | | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, IN 47907
| | - Raka M Mitra
- Department of Biology, Carleton College, Northfield, MN 55057
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23
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Chen M, Chen N, Wang J, Zhou Y, Han L, Shi X, Hikichi Y, Ohnishi K, Li J, Zhang Y. Involvement of a FAD-Linked Oxidase RSc0454 for Expression of the Type III Secretion System and Pathogenicity in Ralstonia solanacearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1228-1235. [PMID: 34374557 DOI: 10.1094/mpmi-07-21-0168-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ralstonia solanacearum RSc0454 is predicted as a FAD-linked oxidase based on protein homologies, while it contains distinct domains of lactate dehydrogenase and succinate dehydrogenase. A previous study demonstrated that RSc0454 exhibits lactate dehydrogenase activity using pyruvate and NADH as substrates, and is essential for pathogenicity of R. solanacearum. Here, we genetically characterized involvement of RSc0454 on bacterial growth and expression of genes for the type III secretion system (T3SS, a pathogenicity determinant) in R. solanacearum. The RSc0454 mutant grew normally in rich medium but grew faintly in host plants, and failed to grow in minimal medium. Supplementary succinate but not lactate could substantially restore some phenotypes of RSc0454 mutants, including faint growth in host plants, diminished growth in the minimal medium, and lost pathogenicity toward host plants. Expression of T3SS genes is directly controlled by a master regulator, HrpB, and hrpB expression is positively regulated by HrpG and PrhG in parallel ways. Deletion of RSc0454 substantially reduced expression levels of hrpB and T3SS both in vitro and in planta. Moreover, RSc0454 is revealed to be required for the T3SS expression via HrpG and PrhG, although through some novel pathway, and impaired expression of these genes was not due to growth deficiency of RSc0454 mutants. RSc0454 is suggested to be important for redox balance inside cells, and supplementary NADH partially restored diminished growth of the RSc0454 mutant in the minimal medium only in the presence of succinate at some moderate concentrations, indicating that the unbalanced redox in the RSc0454 mutant might be responsible for its diminished growth in the minimal medium. Taken together, these results provide novel insights into the understanding of various biological functions of this FAD-linked oxidase RSc0454 and involvement of the redox balance on expression of the T3SS in R. solanacearum.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Min Chen
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Nan Chen
- College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Jiwu Wang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - YuJian Zhou
- Laboratory of Human Micromorphology, Chongqing Medical University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Xiaojun Shi
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Yasufumi Hikichi
- China Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Japan
| | - Kouhei Ohnishi
- China Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Japan
| | - Jing Li
- The Ninth Peoples Hospital of Chongqing, Chongqing, China
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
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Zhou X, Wang Y, Li C, Xu Y, Su X, Yang T, Zhang X. Differential Expression Pattern of Pathogenicity-Related Genes of Ralstonia pseudosolanacearum YQ Responding to Tissue Debris of Casuarina equisetifolia. PHYTOPATHOLOGY 2021; 111:1918-1926. [PMID: 33822646 DOI: 10.1094/phyto-11-20-0490-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ralstonia solanacearum species complex (RSSC) contains a group of destructive plant pathogenic bacteria, causing bacterial wilt of >200 species of crops and trees, such as Casuarina equisetifolia, worldwide. RSSC can survive in the soil environment for a long time and start infection after activation by host plants. This study conducted a transcriptome analysis on the expression pattern of the pathogenicity-related genes of a new isolated RSSC strain YQ (Ralstonia pseudosolanacearum phylotype I-16) in response to C. equisetifolia cladophyll (a branch of a stem that resembles and functions as a leaf) and root debris under in vitro culture. The cladophyll debris induced more genes up-regulated than the root debris, including pathogenicity-related genes involved in motility, effectors, type III secretion systems, quorum sensing, and plant cell wall degradation. Besides, many differentially expressed genes were related to transcriptional regulator such as cyclic dimeric guanosine monophosphate. Moreover, the cultures with cladophyll debris induced a faster wilting in bioassays, and the cell swimming was enhanced by cladophyll exudate. C. equisetifolia cladophylls could activate the expression of pathogenicity-related genes of strain YQ and accelerate infection. Our findings suggest that litterfall management in C. equisetifolia forests, or even other plantations, should receive attention to prevent the induction of bacterial wilt disease caused by RSSC.
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Affiliation(s)
- Xiang Zhou
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Yue Wang
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Chuqiao Li
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Yuanyou Xu
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Xiu Su
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Tian Yang
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
| | - Xinqi Zhang
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou 311300, People's Republic of China
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25
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Wang Y, Zhao A, Morcillo RJL, Yu G, Xue H, Rufian JS, Sang Y, Macho AP. A bacterial effector protein uncovers a plant metabolic pathway involved in tolerance to bacterial wilt disease. MOLECULAR PLANT 2021; 14:1281-1296. [PMID: 33940211 DOI: 10.1016/j.molp.2021.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/15/2021] [Accepted: 04/28/2021] [Indexed: 05/27/2023]
Abstract
Bacterial wilt caused by the soil-borne plant pathogen Ralstonia solanacearum is a devastating disease worldwide. Upon plant colonization, R. solanacearum replicates massively, causing plant wilting and death; collapsed infected tissues then serve as a source of inoculum. In this work, we show that the plant metabolic pathway mediated by pyruvate decarboxylases (PDCs) contributes to plant tolerance to bacterial wilt disease. Arabidopsis and tomato plants respond to R. solanacearum infection by increasing PDC activity, and plants with deficient PDC activity are more susceptible to bacterial wilt. Treatment with either pyruvic acid or acetic acid (substrate and product of the PDC pathway, respectively) enhances plant tolerance to bacterial wilt disease. An effector protein secreted by R. solanacearum, RipAK, interacts with PDCs and inhibits their oligomerization and enzymatic activity. Collectively, our work reveals a metabolic pathway involved in plant resistance to biotic and abiotic stresses, and a bacterial virulence strategy to promote disease and the completion of the pathogenic life cycle.
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Affiliation(s)
- Yaru Wang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China; University of Chinese Academy of Sciences, Beijing, China
| | - Achen Zhao
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China; University of Chinese Academy of Sciences, Beijing, China
| | - Rafael J L Morcillo
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China
| | - Gang Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China
| | - Hao Xue
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jose S Rufian
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China
| | - Yuying Sang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China
| | - Alberto P Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences; Chinese Academy of Sciences, Shanghai 201602, China.
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Pandey A, Moon H, Choi S, Yoon H, Prokchorchik M, Jayaraman J, Sujeevan R, Kang YM, McCann HC, Segonzac C, Kim CM, Park SJ, Sohn KH. Ralstonia solanacearum Type III Effector RipJ Triggers Bacterial Wilt Resistance in Solanum pimpinellifolium. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:962-972. [PMID: 33881922 DOI: 10.1094/mpmi-09-20-0256-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ralstonia solanacearum causes bacterial wilt disease in solanaceous crops. Identification of avirulence type III-secreted effectors recognized by specific disease resistance proteins in host plant species is an important step toward developing durable resistance in crops. In the present study, we show that R. solanacearum effector RipJ functions as an avirulence determinant in Solanum pimpinellifolium LA2093. In all, 10 candidate avirulence effectors were shortlisted based on the effector repertoire comparison between avirulent Pe_9 and virulent Pe_1 strains. Infection assays with transgenic strain Pe_1 individually carrying a candidate avirulence effector from Pe_9 revealed that only RipJ elicits strong bacterial wilt resistance in S. pimpinellifolium LA2093. Furthermore, we identified that several RipJ natural variants do not induce bacterial wilt resistance in S. pimpinellifolium LA2093. RipJ belongs to the YopJ family of acetyltransferases. Our sequence analysis indicated the presence of partially conserved putative catalytic residues. Interestingly, the conserved amino acid residues in the acetyltransferase catalytic triad are not required for effector-triggered immunity. In addition, we show that RipJ does not autoacetylate its lysine residues. Our study reports the identification of the first R. solanacearum avirulence protein that triggers bacterial wilt resistance in tomato. We expect that our discovery of RipJ as an avirulence protein will accelerate the development of bacterial wilt-resistant tomato varieties in the future.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Ankita Pandey
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hayoung Moon
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sera Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hayeon Yoon
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Maxim Prokchorchik
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Germany
| | - Jay Jayaraman
- New Zealand Institute for Plant & Food Research Limited (PFR), Mt Albert Auckland 1025, New Zealand
| | - Rajendran Sujeevan
- Division of Biological Sciences and Research Institute for Basic Science, Wonkwang University, Iksan 54538, Republic of Korea
| | - Yu Mi Kang
- Division of Horticulture Industry, Wonkwang University, Iksan 554438, Republic of Korea
| | - Honour C McCann
- Institute of Advanced Studies, Massey University, Auckland 0745, New Zealand
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Cécile Segonzac
- Department of Plant Science, Plant Genome and Breeding Institute, Agricultural Life Science Research Institute, Seoul National University, 08826, Seoul, Republic of Korea
- Plant Immunity Research Center, Seoul National University, 08826, Seoul, Republic of Korea
- Department of Agriculture, Forestry and Bioresources, Seoul National University, 08826, Seoul, Republic of Korea
| | - Chul Min Kim
- Division of Horticulture Industry, Wonkwang University, Iksan 554438, Republic of Korea
| | - Soon Ju Park
- Division of Biological Sciences and Research Institute for Basic Science, Wonkwang University, Iksan 54538, Republic of Korea
| | - Kee Hoon Sohn
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- School of Interdisciplinary Biosciences and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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27
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Schachterle JK, Huang Q. Implication of the Type III Effector RipS1 in the Cool-Virulence of Ralstonia solanacearum Strain UW551. FRONTIERS IN PLANT SCIENCE 2021; 12:705717. [PMID: 34367225 PMCID: PMC8339923 DOI: 10.3389/fpls.2021.705717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Members of the Ralstonia solanacearum species complex cause a variety of wilting diseases across a wide range of hosts by colonizing and blocking xylem vessels. Of great concern are race 3 biovar 2 strains of R. solanacearum capable of causing brown rot of potato at cool temperatures, which are select agents in the United States. To gain a better understanding of cool-virulence mechanisms, we generated libraries of transposon mutants in the cool-virulent R. solanacearum strain UW551 and screened 10,000 mutants using our seedling assay for significantly reduced virulence at 20°C. We found several mutants that exhibited reduced virulence at 28 and 20°C and also mutants that were only affected at the cooler temperature. One mutant of the latter chosen for further study had the transposon inserted in an intergenic region between a type III secretion system effector gene ripS1 and a major facilitator superfamily (MFS) protein gene. Gene expression analysis showed that expression of ripS1 was altered by the transposon insertion, but not the MFS protein gene. An independent mutant with this insertion upstream of ripS1 was generated and used to confirm virulence and gene expression phenotypes. The effector, RipS1, has unknown function and is part of a family of effectors belonging to the largest known type III effectors. The functional connection between RipS1 and cool-virulence of R. solanacearum UW551 suggests that RipS1 (and/or its upstream promoter element) may serve as a potential target for development of cool-virulence-specific diagnostic tools to differentiate the highly regulated cool-virulent strains from non-cool-virulent strains of R. solanacearum. Our results provide important information for continued work toward a better understanding of cool-virulence of R. solanacearum and development of proper control strategies to combat this important plant pathogen.
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Affiliation(s)
| | - Qi Huang
- Floral and Nursery Plants Research Unit, United States National Arboretum, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD, United States
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28
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Moon H, Pandey A, Yoon H, Choi S, Jeon H, Prokchorchik M, Jung G, Witek K, Valls M, McCann HC, Kim M, Jones JDG, Segonzac C, Sohn KH. Identification of RipAZ1 as an avirulence determinant of Ralstonia solanacearum in Solanum americanum. MOLECULAR PLANT PATHOLOGY 2021; 22:317-333. [PMID: 33389783 PMCID: PMC7865085 DOI: 10.1111/mpp.13030] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/07/2020] [Accepted: 11/23/2020] [Indexed: 05/08/2023]
Abstract
Ralstonia solanacearum causes bacterial wilt disease in many plant species. Type III-secreted effectors (T3Es) play crucial roles in bacterial pathogenesis. However, some T3Es are recognized by corresponding disease resistance proteins and activate plant immunity. In this study, we identified the R. solanacearum T3E protein RipAZ1 (Ralstonia injected protein AZ1) as an avirulence determinant in the black nightshade species Solanum americanum. Based on the S. americanum accession-specific avirulence phenotype of R. solanacearum strain Pe_26, 12 candidate avirulence T3Es were selected for further analysis. Among these candidates, only RipAZ1 induced a cell death response when transiently expressed in a bacterial wilt-resistant S. americanum accession. Furthermore, loss of ripAZ1 in the avirulent R. solanacearum strain Pe_26 resulted in acquired virulence. Our analysis of the natural sequence and functional variation of RipAZ1 demonstrated that the naturally occurring C-terminal truncation results in loss of RipAZ1-triggered cell death. We also show that the 213 amino acid central region of RipAZ1 is sufficient to induce cell death in S. americanum. Finally, we show that RipAZ1 may activate defence in host cell cytoplasm. Taken together, our data indicate that the nucleocytoplasmic T3E RipAZ1 confers R. solanacearum avirulence in S. americanum. Few avirulence genes are known in vascular bacterial phytopathogens and ripAZ1 is the first one in R. solanacearum that is recognized in black nightshades. This work thus opens the way for the identification of disease resistance genes responsible for the specific recognition of RipAZ1, which can be a source of resistance against the devastating bacterial wilt disease.
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Affiliation(s)
- Hayoung Moon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Ankita Pandey
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hayeon Yoon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Sera Choi
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hyelim Jeon
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Maxim Prokchorchik
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Gayoung Jung
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Kamil Witek
- The Sainsbury LaboratoryUniversity of East AngliaNorwichUK
| | - Marc Valls
- Department of GeneticsUniversity of BarcelonaBarcelonaSpain
- Centre for Research in Agricultural Genomics (CSIC‐IRTA‐UAB‐UB)BellaterraSpain
| | - Honour C. McCann
- New Zealand Institute of Advanced StudiesMassey UniversityAucklandNew Zealand
- Max Planck Institute for Developmental BiologyTübingenGermany
| | - Min‐Sung Kim
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- Division of Integrative Biosciences and BiotechnologyPohang University of Science and TechnologyRepublic of Korea
| | | | - Cécile Segonzac
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
- Department of Plant Science, Plant Genomics and Breeding InstituteAgricultural Life Science Research InstituteSeoul National UniversitySeoulRepublic of Korea
| | - Kee Hoon Sohn
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- School of Interdisciplinary Bioscience and BioengineeringPohang University of Science and TechnologyPohangRepublic of Korea
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29
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Nakano M, Ichinose Y, Mukaihara T. Ralstonia solanacearum Type III Effector RipAC Targets SGT1 to Suppress Effector-Triggered Immunity. PLANT & CELL PHYSIOLOGY 2021; 61:2067-2076. [PMID: 32991707 DOI: 10.1093/pcp/pcaa122] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Ralstonia solanacearum injects type III effectors into host cells to cause bacterial wilt in Solanaceae plants. To identify R. solanacearum effectors that suppress effector-triggered immunity (ETI) in plants, we evaluated R. solanacearum RS1000 effectors for their ability to suppress a hypersensitive response (HR) induced by the avirulence (Avr) effector RipAA in Nicotiana benthamiana. Out of the 11 effectors tested, 4 suppressed RipAA-triggered HR cell death. Among them, RipAC contains tandem repeats of the leucine-rich repeat (LRR) motif, which serves as the structural scaffold for a protein-protein interaction. We found that the LRR domain of RipAC was indispensable for the suppression of HR cell death during the recognition of RipAA and another Avr effector RipP1. By yeast two-hybrid screening, we identified N. benthamiana SGT1, an adaptor protein that forms a molecular chaperone complex with RAR1, as a host factor of the RipAC target. RipAC interacted with NbSGT1 in yeast and plant cells. Upon the formation of the molecular chaperone complex, the presence of RipAC markedly inhibits the interaction between NbSGT1 and NbRAR1. The RipAA- and RipP1-triggered HR cell deaths were not observed in NbSGT1-silenced plants. The introduction of RipAC was complementary to the reduced growth of the R. solanacearum mutant strain in N. benthamiana. These findings indicate that R. solanacearum uses RipAC to subvert the NbSGT1-mediated formation of the molecular chaperone complex and suppress ETI responses during the recognition of Avr effectors.
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Affiliation(s)
- Masahito Nakano
- Graduate School of Environmental and Life Science, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530 Japan
| | - Yuki Ichinose
- Graduate School of Environmental and Life Science, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530 Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama, 716-1241 Japan
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30
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Landry D, González‐Fuente M, Deslandes L, Peeters N. The large, diverse, and robust arsenal of Ralstonia solanacearum type III effectors and their in planta functions. MOLECULAR PLANT PATHOLOGY 2020; 21:1377-1388. [PMID: 32770627 PMCID: PMC7488467 DOI: 10.1111/mpp.12977] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/15/2020] [Accepted: 06/22/2020] [Indexed: 05/25/2023]
Abstract
The type III secretion system with its delivered type III effectors (T3Es) is one of the main virulence determinants of Ralstonia solanacearum, a worldwide devastating plant pathogenic bacterium affecting many crop species. The pan-effectome of the R. solanacearum species complex has been exhaustively identified and is composed of more than 100 different T3Es. Among the reported strains, their content ranges from 45 to 76 T3Es. This considerably large and varied effectome could be considered one of the factors contributing to the wide host range of R. solanacearum. In order to understand how R. solanacearum uses its T3Es to subvert the host cellular processes, many functional studies have been conducted over the last three decades. It has been shown that R. solanacearum effectors, as those from other plant pathogens, can suppress plant defence mechanisms, modulate the host metabolism, or avoid bacterial recognition through a wide variety of molecular mechanisms. R. solanacearum T3Es can also be perceived by the plant and trigger immune responses. To date, the molecular mechanisms employed by R. solanacearum T3Es to modulate these host processes have been described for a growing number of T3Es, although they remain unknown for the majority of them. In this microreview, we summarize and discuss the current knowledge on the characterized R. solanacearum species complex T3Es.
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Affiliation(s)
- David Landry
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
| | - Manuel González‐Fuente
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
| | - Laurent Deslandes
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
| | - Nemo Peeters
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
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31
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Medina-Puche L, Tan H, Dogra V, Wu M, Rosas-Diaz T, Wang L, Ding X, Zhang D, Fu X, Kim C, Lozano-Duran R. A Defense Pathway Linking Plasma Membrane and Chloroplasts and Co-opted by Pathogens. Cell 2020; 182:1109-1124.e25. [DOI: 10.1016/j.cell.2020.07.020] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/23/2020] [Accepted: 07/15/2020] [Indexed: 12/22/2022]
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32
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Lei N, Chen L, Kiba A, Hikichi Y, Zhang Y, Ohnishi K. Super-Multiple Deletion Analysis of Type III Effectors in Ralstonia solanacearum OE1-1 for Full Virulence Toward Host Plants. Front Microbiol 2020; 11:1683. [PMID: 32849353 PMCID: PMC7409329 DOI: 10.3389/fmicb.2020.01683] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/29/2020] [Indexed: 11/16/2022] Open
Abstract
Ralstonia solanacearum species complex (RSSC) posses extremely abundant type III effectors (T3Es) that are translocated into plant cells via a syringe-like apparatus assembled by a type III secretion system (T3SS) to subvert host defense initiated by innate immunity. More than 100 T3Es are predicted among different RSSC strains, with an average of about 70 T3Es in each strain. Among them, 32 T3Es are found to be conserved among the RSSC and hence called the core T3Es. Here, we genetically characterized contribution of abundant T3Es to virulence of a Japanese RSSC strain OE1-1 toward host plants. While all the T3Es members of AWR family contributed slightly to virulence, those of the GALA, HLK, and SKWP families did not influence full virulence of OE1-1. Mutant OE1-1D21E (with deletion of all 21 T3Es members of four families) exhibited slightly impaired virulence, while mutant OE1-1D36E (deleting all 21 T3Es of 4 families and 15 core T3Es) exhibited substantially reduced virulence. Mutant OE1-1D42E (deleting all 21 T3Es of 4 families, 15 core T3Es and 6 extended core T3Es) failed to cause any disease on tobacco plants with leaf infiltration but retained faint virulence on tobacco plants with petiole inoculation. The proliferation of mutant OE1-1D42E in tobacco stems was substantially impaired with about three orders of magnitude less than that of OE1-1, while no impact in tobacco leaves if directly infiltrated into leaves. On the contrary, the OE1-1D42E mutant retained faint virulence on eggplants with leaf infiltration but completely lost virulence on eggplants with root-cutting inoculation. The proliferation of OE1-1D42E mutant both in eggplant leaves and stems was substantially impaired. Intriguingly, mutant OE1-1D42E still caused necrotic lesions in tobacco and eggplant leaves, indicating that some other than the 42 removed effectors are involved in expansion of necrotic lesions in host leaves. All taken together, we here genetically demonstrated that all the core and extended core T3Es are nearly crucial for virulence of OE1-1 toward host plants and provided currently a kind of T3Es-free strain that enables primary functional studies of individual T3Es in host cells.
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Affiliation(s)
- Ni Lei
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Japan
| | - Li Chen
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi'an, China
| | - Akinori Kiba
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China.,Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi University, Kochi, Japan
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Sang Y, Yu W, Zhuang H, Wei Y, Derevnina L, Yu G, Luo J, Macho AP. Intra-strain Elicitation and Suppression of Plant Immunity by Ralstonia solanacearum Type-III Effectors in Nicotiana benthamiana. PLANT COMMUNICATIONS 2020; 1:100025. [PMID: 33367244 PMCID: PMC7747989 DOI: 10.1016/j.xplc.2020.100025] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/12/2019] [Accepted: 01/16/2020] [Indexed: 05/11/2023]
Abstract
Effector proteins delivered inside plant cells are powerful weapons for bacterial pathogens, but this exposes the pathogen to potential recognition by the plant immune system. Therefore, the effector repertoire of a given pathogen must be balanced for a successful infection. Ralstonia solanacearum is an aggressive pathogen with a large repertoire of secreted effectors. One of these effectors, RipE1, is conserved in most R. solanacearum strains sequenced to date. In this work, we found that RipE1 triggers immunity in N. benthamiana, which requires the immune regulator SGT1, but not EDS1 or NRCs. Interestingly, RipE1-triggered immunity induces the accumulation of salicylic acid (SA) and the overexpression of several genes encoding phenylalanine-ammonia lyases (PALs), suggesting that the unconventional PAL-mediated pathway is responsible for the observed SA biosynthesis. Surprisingly, RipE1 recognition also induces the expression of jasmonic acid (JA)-responsive genes and JA biosynthesis, suggesting that both SA and JA may act cooperatively in response to RipE1. We further found that RipE1 expression leads to the accumulation of glutathione in plant cells, which precedes the activation of immune responses. R. solanacearum secretes another effector, RipAY, which is known to inhibit immune responses by degrading cellular glutathione. Accordingly, RipAY inhibits RipE1-triggered immune responses. This work shows a strategy employed by R. solanacearum to counteract the perception of its effector proteins by plant immune system.
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Affiliation(s)
- Yuying Sang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Wenjia Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haiyan Zhuang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Yali Wei
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lida Derevnina
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich NR4 7UH, UK
| | - Gang Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Jiamin Luo
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
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Li J, Han L, Chen N, Zhu C, Gao Y, Shi X, Xu C, Hikichi Y, Zhang Y, Ohnishi K. Functional Characterization of RsRsgA for Ribosome Biosynthesis and Expression of the Type III Secretion System in Ralstonia solanacearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:972-981. [PMID: 32240066 DOI: 10.1094/mpmi-10-19-0294-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
RsgA plays an important role in maturation of 30S subunit in many bacteria that assists in the release of RbfA from the 30S subunit during a late stage of ribosome biosynthesis. Here, we genetically characterized functional roles of RsgA in Ralstonia solanacearum, hereafter designated RsRsgA. Deletion of R. solanacearum rsgA or rbfA resulted in distinct deficiency of 16S ribosomal RNA, significantly slowed growth in broth medium, and diminished growth in nutrient-limited medium, which are similar as phenotypes of rsgA mutants and rbfA mutants of Escherichia coli and other bacteria. Our gene-expression studies revealed that RsRsgA is important for expression of genes encoding the type III secretion system (T3SS) (a pathogenicity determinant of R. solanacearum) both in vitro and in planta. Compared with the wild-type R. solanacearum strain, proliferation of the rsgA and rbfA mutants in tobacco leaves was significantly impaired, while they failed to migrate into tobacco xylem vessels from infiltrated leaves, and hence, these two mutants failed to cause any bacterial wilt disease in tobacco plants. It was further revealed that rsgA expression was highly enhanced under nutrient-limited conditions compared with that in broth medium and RsRsgA affects T3SS expression through the PrhN-PrhG-HrpB pathway. Moreover, expression of a subset of type III effectors was substantially impaired in the rsgA mutant, some of which are responsible for R. solanacearum GMI1000 elicitation of a hypersensitive response (HR) in tobacco leaves, while RsRsgA is not required for HR elicitation of GMI1000 in tobacco leaves. All these results provide novel insights into understanding various biological functions of RsgA proteins and complex regulation on the T3SS in R. solanacearum.
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Affiliation(s)
- Jiaman Li
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Nan Chen
- College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Chao Zhu
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yuwei Gao
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Xiaojun Shi
- College of Resources and Environment, Southwest University, Chongqing, China
- Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Chongqing, China
| | - Changzheng Xu
- College of Life Science, Southwest University, Chongqing, China
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Chongqing, China
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
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Zhang Y, Han L, Zhang L, Xu C, Shi X, Hikichi Y, Ohnishi K. Expression of Ralstonia solanacearum type III secretion system is dependent on a novel type 4 pili (T4P) assembly protein (TapV) but is T4P independent. MOLECULAR PLANT PATHOLOGY 2020; 21:777-793. [PMID: 32196936 PMCID: PMC7214476 DOI: 10.1111/mpp.12930] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/08/2020] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
Type IV pili (T4P) are virulence factors in various pathogenic bacteria of animals and plants that play important roles in twitching motility, swimming motility, biofilm formation, and adhesion to host cells. Here, we genetically characterized functional roles of a putative T4P assembly protein TapV (Rsc1986 in reference strain GMI1000) and its homologue Rsp0189, which shares 58% amino acid identity with TapV, in Ralstonia solanacearum. Deletion of tapV, but not rsp0189, resulted in significantly impaired twitching motility, swimming motility, and adhesion to tomato roots, which are consistent as phenotypes of the pilA mutant (a known R. solanacearum T4P-deficient mutant). However, unlike the pilA mutant, the tapV mutant produced more biofilm than the wild-type strain. Our gene expression studies revealed that TapV, but not Rsp0189, is important for expression of a type III secretion system (T3SS, a pathogenicity determinant of R. solanacearum) both in vitro and in planta, but it is T4P independent. We further revealed that TapV affected the T3SS expression via the PhcA-TapV-PrhG-HrpB pathway, consistent with previous reports that PhcA positively regulates expression of pilA and prhG. Moreover, deletion of tapV, but not rsp0189, significantly impaired the ability to migrate into and colonize xylem vessels of host plants, but there was no alteration in intercellular proliferation of R. solanacearum in tobacco leaves, which is similar to the pilA mutant. The tapV mutant showed significantly impaired virulence in host plants. This is the first report on the impact of T4P components on the T3SS, providing novel insights into our understanding of various biological functions of T4P and the complex regulatory pathway of T3SS in R. solanacearum.
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Affiliation(s)
- Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqingChina
| | - Liangliang Han
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Research Institute of Molecular GeneticsKochi UniversityKochiJapan
| | - Lichun Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Research Institute of Molecular GeneticsKochi UniversityKochiJapan
| | - Changzheng Xu
- College of Life scienceSouthwest UniversityChongqingChina
| | - Xiaojun Shi
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqingChina
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityKochiJapan
| | - Kouhei Ohnishi
- Research Institute of Molecular GeneticsKochi UniversityKochiJapan
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36
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Su Y, Xu Y, Li Q, Yuan G, Zheng D. The essential genome of Ralstonia solanacearum. Microbiol Res 2020; 238:126500. [PMID: 32502949 DOI: 10.1016/j.micres.2020.126500] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/27/2020] [Accepted: 04/30/2020] [Indexed: 01/13/2023]
Abstract
Ralstonia solanacearum is a scientifically/economically important plant pathogenic bacterium. The plant disease caused by R. solanacearum causes huge economic losses, and efficient control measures for the disease remain limited. To gain a better system-level understanding of R. solanacearum, we generated a near-saturated transposon insertion library of R. solanacearum GMI1000 with approximately 240,000 individual insertion mutants. Transposon sequencing (Tn-seq) allowed the mapping of 70.44%-80.96% of all potential insertion sites of the mariner C9 transposase in the genome of R. solanacearum and the identification of 465 genes essential for the growth of R. solanacearum in rich medium. Functional and comparative analyses of essential genes revealed that many basic physiological and biochemical processes such as transcription differ between R. solanacearum and other bacteria. A comparative analysis of essential genes also suggested that 34 genes might be essential only for Ralstonia group bacteria, whereas another 16 essential genes are unique to Ralstonia, providing high-priority candidate targets for developing R. solanacearum-specific drugs.
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Affiliation(s)
- Yaxing Su
- National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning 530004, PR China
| | - Yanan Xu
- Pharmaceutical College, Guangxi Medical University, Nanning 530021, PR China
| | - Qiqin Li
- National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning 530004, PR China
| | - Gaoqing Yuan
- National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning 530004, PR China
| | - Dehong Zheng
- National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning 530004, PR China.
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37
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Zalguizuri A, Caetano-Anollés G, Lepek VC. Phylogenetic profiling, an untapped resource for the prediction of secreted proteins and its complementation with sequence-based classifiers in bacterial type III, IV and VI secretion systems. Brief Bioinform 2020; 20:1395-1402. [PMID: 29394318 DOI: 10.1093/bib/bby009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 01/15/2018] [Indexed: 12/29/2022] Open
Abstract
In the establishment and maintenance of the interaction between pathogenic or symbiotic bacteria with a eukaryotic organism, protein substrates of specialized bacterial secretion systems called effectors play a critical role once translocated into the host cell. Proteins are also secreted to the extracellular medium by free-living bacteria or directly injected into other competing organisms to hinder or kill. In this work, we explore an approach based on the evolutionary dependence that most of the effectors maintain with their specific secretion system that analyzes the co-occurrence of any orthologous protein group and their corresponding secretion system across multiple genomes. We compared and complemented our methodology with sequence-based machine learning prediction tools for the type III, IV and VI secretion systems. Finally, we provide the predictive results for the three secretion systems in 1606 complete genomes at http://www.iib.unsam.edu.ar/orgsissec/.
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Sun T, Wu W, Wu H, Rou W, Zhou Y, Zhuo T, Fan X, Hu X, Zou H. Ralstonia solanacearum elicitor RipX Induces Defense Reaction by Suppressing the Mitochondrial atpA Gene in Host Plant. Int J Mol Sci 2020; 21:E2000. [PMID: 32183439 PMCID: PMC7139787 DOI: 10.3390/ijms21062000] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 11/16/2022] Open
Abstract
RipX of Ralstonia solanacearum is translocated into host cells by a type III secretion system and acts as a harpin-like protein to induce a hypersensitive response in tobacco plants. The molecular events in association with RipX-induced signaling transduction have not been fully elucidated. This work reports that transient expression of RipX induced a yellowing phenotype in Nicotiana benthamiana, coupled with activation of the defense reaction. Using yeast two-hybrid and split-luciferase complementation assays, mitochondrial ATP synthase F1 subunit α (ATPA) was identified as an interaction partner of RipX from N. benthamiana. Although a certain proportion was found in mitochondria, the YFP-ATPA fusion was able to localize to the cell membrane, cytoplasm, and nucleus. RFP-RipX fusion was found from the cell membrane and cytoplasm. Moreover, ATPA interacted with RipX at both the cell membrane and cytoplasm in vivo. Silencing of the atpA gene had no effect on the appearance of yellowing phenotype induced by RipX. However, the silenced plants improved the resistance to R. solanacearum. Moreover, qRT-PCR and promoter GUS fusion experiments revealed that the transcript levels of atpA were evidently reduced in response to expression of RipX. These data demonstrated that RipX exerts a suppressive effect on the transcription of atpA gene, to induce defense reaction in N. benthamiana.
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Affiliation(s)
- Tingyan Sun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Wei Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Haoxiang Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Wei Rou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Yinghui Zhou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Tao Zhuo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Xiaojing Fan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Xun Hu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Huasong Zou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
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Characterization of the mechanism of thioredoxin-dependent activation of γ-glutamylcyclotransferase, RipAY, from Ralstonia solanacearum. Biochem Biophys Res Commun 2020; 523:759-765. [PMID: 31948763 DOI: 10.1016/j.bbrc.2019.12.092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 12/24/2019] [Indexed: 12/21/2022]
Abstract
A class II ChaC protein, RipAY, from phytopathogenic bacterium, Ralstonia solanacearum exhibits γ-glutamylcyclotransferase (GGCT) activity to degrade intracellular glutathione in host cells upon its interaction with host thioredoxins (Trxs). To understand the Trx-dependent activation of RipAY, we constructed various deletion mutants of RipAY and found the determinant region for GGCT activation in the N- and C-terminal sequences of RipAY by analyzing their yeast growth inhibition activity and the interaction with Trxs. Mutational analysis of the active site cysteine residues of Arabidopsis thaliana Trx-h5 (AtTrx-h5), one of the most efficiently stimulating Trxs, revealed that each active site cysteine residue of AtTrx-h5 contributes to efficient RipAY-binding and -activation activity. We also estimated that RipAY and AtTrx-h5 form a complex at a 1:2 M ratio. Furthermore, we found that the constitutive GGCT activity of Gcg1, a yeast class I ChaC protein, is also stimulated by yeast Trx1. These results indicate that class I ChaC proteins can sense the intracellular redox state and interact with Trxs to promote more efficient degradation of glutathione and regulate intracellular redox homeostasis. We hypothesize that RipAY acquired a more efficient and specific Trx-dependent activation mechanism to activate its GGCT activity only in the host eukaryotic cells during the evolution.
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Nakano M, Mukaihara T. Comprehensive Identification of PTI Suppressors in Type III Effector Repertoire Reveals that Ralstonia solanacearum Activates Jasmonate Signaling at Two Different Steps. Int J Mol Sci 2019; 20:E5992. [PMID: 31795135 PMCID: PMC6928842 DOI: 10.3390/ijms20235992] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 02/04/2023] Open
Abstract
Ralstonia solanacearum is the causative agent of bacterial wilt in many plants. To identify R. solanacearum effectors that suppress pattern-triggered immunity (PTI) in plants, we transiently expressed R. solanacearum RS1000 effectors in Nicotiana benthamiana leaves and evaluated their ability to suppress the production of reactive oxygen species (ROS) triggered by flg22. Out of the 61 effectors tested, 11 strongly and five moderately suppressed the flg22-triggered ROS burst. Among them, RipE1 shared homology with the Pseudomonas syringae cysteine protease effector HopX1. By yeast two-hybrid screening, we identified jasmonate-ZIM-domain (JAZ) proteins, which are transcriptional repressors of the jasmonic acid (JA) signaling pathway in plants, as RipE1 interactors. RipE1 promoted the degradation of JAZ repressors and induced the expressions of JA-responsive genes in a cysteine-protease-activity-dependent manner. Simultaneously, RipE1, similarly to the previously identified JA-producing effector RipAL, decreased the expression level of the salicylic acid synthesis gene that is required for the defense responses against R. solanacearum. The undecuple mutant that lacks 11 effectors with a strong PTI suppression activity showed reduced growth of R. solanacearum in Nicotiana plants. These results indicate that R. solanacearum subverts plant PTI responses using multiple effectors and manipulates JA signaling at two different steps to promote infection.
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Affiliation(s)
- Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241, Japan
- Graduate School of Environmental and Life Science, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241, Japan
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Wu D, von Roepenack-Lahaye E, Buntru M, de Lange O, Schandry N, Pérez-Quintero AL, Weinberg Z, Lowe-Power TM, Szurek B, Michael AJ, Allen C, Schillberg S, Lahaye T. A Plant Pathogen Type III Effector Protein Subverts Translational Regulation to Boost Host Polyamine Levels. Cell Host Microbe 2019; 26:638-649.e5. [DOI: 10.1016/j.chom.2019.09.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/21/2019] [Accepted: 09/23/2019] [Indexed: 01/21/2023]
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42
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Zhang Y, Zhang W, Han L, Li J, Shi X, Hikichi Y, Ohnishi K. Involvement of a PadR regulator PrhP on virulence of Ralstonia solanacearum by controlling detoxification of phenolic acids and type III secretion system. MOLECULAR PLANT PATHOLOGY 2019; 20:1477-1490. [PMID: 31392803 PMCID: PMC6804342 DOI: 10.1111/mpp.12854] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Ralstonia solanacearum can metabolize ferulic acid (FA) and salicylic acid (SA), two representative phenolic acids, to protect it from toxicity of phenolic acids. Here, we genetically demonstrated a novel phenolic acid decarboxylase regulator (PadR)-like regulator PrhP as a positive regulator on detoxification of SA and FA in R. solanacearum. Although the ability to degrade SA and FA enhances the infection process of R. solanacearum toward host plants, PrhP greatly contributes to the infection process besides degradation of SA and FA. Our results from the growth assay, promoter activity assay, RNA-seq and qRT-PCR revealed that PrhP plays multiple roles in the virulence of R. solanacearum: (1) positively regulates expression of genes for degradation of SA and FA; (2) positively regulates expression of genes encoding type III secretion system (T3SS) and type III effectors both in vitro and in planta; (3) positively regulates expression of many virulence-related genes, such as the flagella, type IV pili and cell wall degradation enzymes; and (4) is important for the extensive proliferation in planta. The T3SS is one of the essential pathogenicity determinants in many pathogenic bacteria, and PrhP positively regulates its expression mediated with the key regulator HrpB but through some novel pathway to HrpB in R. solanacearum. This is the first report on PadR regulators to regulate the T3SS and it could improve our understanding of the various biological functions of PadR regulators and the complex regulatory pathway on T3SS in R. solanacearum.
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Affiliation(s)
- Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqing
| | - Weiqi Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Liangliang Han
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Research Institute of Molecular Genetics, Kochi UniversityKochiJapan
| | - Jing Li
- The Ninth Peoples Hospital of ChongqingChongqingChina
| | - Xiaojun Shi
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Key Laboratory of Efficient Utilization of Soil and Fertilizer ResourcesChongqing
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityKochiJapan
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi UniversityKochiJapan
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Nakano M, Mukaihara T. The type III effector RipB from Ralstonia solanacearum RS1000 acts as a major avirulence factor in Nicotiana benthamiana and other Nicotiana species. MOLECULAR PLANT PATHOLOGY 2019; 20:1237-1251. [PMID: 31218811 PMCID: PMC6715614 DOI: 10.1111/mpp.12824] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt in solanaceous crops. This pathogen injects approximately 70 effector proteins into plant cells via the Hrp type III secretion system in an early stage of infection. To identify an as-yet-unidentified avirulence factor possessed by the Japanese tobacco-avirulent strain RS1000, we transiently expressed RS1000 effectors in Nicotiana benthamiana leaves and monitored their ability to induce effector-triggered immunity (ETI). The expression of RipB strongly induced the production of reactive oxygen species and the expressions of defence-related genes in N. benthamiana. The ripB mutant of RS1002, a nalixidic acid-resistant derivative of RS1000, caused wilting symptoms in N. benthamiana. A pathogenicity test using R. solanacearum mutants revealed that the two already known avirulence factors RipP1 and RipAA contribute in part to the avirulence of RS1002 in N. benthamiana. The Japanese tobacco-virulent strain BK1002 contains mutations in ripB and expresses a C-terminal-truncated RipB that lost the ability to induce ETI in N. benthamiana, indicating a fine-tuning of the pathogen effector repertoire to evade plant recognition. RipB shares homology with Xanthomonas XopQ, which is recognized by the resistance protein Roq1. The RipB-induced resistance against R. solanacearum was abolished in Roq1-silenced plants. These findings indicate that RipB acts as a major avirulence factor in N. benthamiana and that Roq1 is involved in the recognition of RipB.
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Affiliation(s)
- Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS)Yoshikawa, Kibichuo‐choOkayama716‐1241Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS)Yoshikawa, Kibichuo‐choOkayama716‐1241Japan
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Tan X, Qiu H, Li F, Cheng D, Zheng X, Wang B, Huang M, Li W, Li Y, Sang K, Song B, Du J, Chen H, Xie C. Complete Genome Sequence of Sequevar 14M Ralstonia solanacearum Strain HA4-1 Reveals Novel Type III Effectors Acquired Through Horizontal Gene Transfer. Front Microbiol 2019; 10:1893. [PMID: 31474968 PMCID: PMC6703095 DOI: 10.3389/fmicb.2019.01893] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/31/2019] [Indexed: 01/08/2023] Open
Abstract
Ralstonia solanacearum, which causes bacterial wilt in a broad range of plants, is considered a "species complex" due to its significant genetic diversity. Recently, we have isolated a new R. solanacearum strain HA4-1 from Hong'an county in Hubei province of China and identified it being phylotype I, sequevar 14M (phylotype I-14M). Interestingly, we found that it can cause various disease symptoms among different potato genotypes and display different pathogenic behavior compared to a phylogenetically related strain, GMI1000. To dissect the pathogenic mechanisms of HA4-1, we sequenced its whole genome by combined sequencing technologies including Illumina HiSeq2000, PacBio RS II, and BAC-end sequencing. Genome assembly results revealed the presence of a conventional chromosome, a megaplasmid as well as a 143 kb plasmid in HA4-1. Comparative genome analysis between HA4-1 and GMI1000 shows high conservation of the general virulence factors such as secretion systems, motility, exopolysaccharides (EPS), and key regulatory factors, but significant variation in the repertoire and structure of type III effectors, which could be the determinants of their differential pathogenesis in certain potato species or genotypes. We have identified two novel type III effectors that were probably acquired through horizontal gene transfer (HGT). These novel R. solanacearum effectors display homology to several YopJ and XopAC family members. We named them as RipBR and RipBS. Notably, the copy of RipBR on the plasmid is a pseudogene, while the other on the megaplasmid is normal. For RipBS, there are three copies located in the megaplasmid and plasmid, respectively. Our results have not only enriched the genome information on R. solanacearum species complex by sequencing the first sequevar 14M strain and the largest plasmid reported in R. solanacearum to date but also revealed the variation in the repertoire of type III effectors. This will greatly contribute to the future studies on the pathogenic evolution, host adaptation, and interaction between R. solanacearum and potato.
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Affiliation(s)
- Xiaodan Tan
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Huishan Qiu
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Feng Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Dong Cheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Xueao Zheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Bingsen Wang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Mengshu Huang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Wenhao Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Yanping Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Kangqi Sang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
| | - Botao Song
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Juan Du
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Huilan Chen
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Conghua Xie
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
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Cho H, Song ES, Heu S, Baek J, Lee YK, Lee S, Lee SW, Park DS, Lee TH, Kim JG, Hwang I. Prediction of Host-Specific Genes by Pan-Genome Analyses of the Korean Ralstonia solanacearum Species Complex. Front Microbiol 2019; 10:506. [PMID: 30930881 PMCID: PMC6428702 DOI: 10.3389/fmicb.2019.00506] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/27/2019] [Indexed: 12/20/2022] Open
Abstract
The soil-borne pathogenic Ralstonia solanacearum species complex (RSSC) is a group of plant pathogens that is economically destructive worldwide and has a broad host range, including various solanaceae plants, banana, ginger, sesame, and clove. Previously, Korean RSSC strains isolated from samples of potato bacterial wilt were grouped into four pathotypes based on virulence tests against potato, tomato, eggplant, and pepper. In this study, we sequenced the genomes of 25 Korean RSSC strains selected based on these pathotypes. The newly sequenced genomes were analyzed to determine the phylogenetic relationships between the strains with average nucleotide identity values, and structurally compared via multiple genome alignment using Mauve software. To identify candidate genes responsible for the host specificity of the pathotypes, functional genome comparisons were conducted by analyzing pan-genome orthologous group (POG) and type III secretion system effectors (T3es). POG analyses revealed that a total of 128 genes were shared only in tomato-non-pathogenic strains, 8 genes in tomato-pathogenic strains, 5 genes in eggplant-non-pathogenic strains, 7 genes in eggplant-pathogenic strains, 1 gene in pepper-non-pathogenic strains, and 34 genes in pepper-pathogenic strains. When we analyzed T3es, three host-specific effectors were predicted: RipS3 (SKWP3) and RipH3 (HLK3) were found only in tomato-pathogenic strains, and RipAC (PopC) were found only in eggplant-pathogenic strains. Overall, we identified host-specific genes and effectors that may be responsible for virulence functions in RSSC in silico. The expected characters of those genes suggest that the host range of RSSC is determined by the comprehensive actions of various virulence factors, including effectors, secretion systems, and metabolic enzymes.
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Affiliation(s)
- Heejung Cho
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Eun-Sung Song
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Sunggi Heu
- National Institute of Crop Science, Rural Development Administration, Jeonju, South Korea
| | - JeongHo Baek
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Young Kee Lee
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Seungdon Lee
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Seon-Woo Lee
- Department of Applied Biology, Dong-A University, Busan, South Korea
| | - Dong Suk Park
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Tae-Ho Lee
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Jeong-Gu Kim
- National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Ingyu Hwang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
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Zhang W, Li J, Shi X, Hikichi Y, Zhang Y, Ohnishi K. Functional Characterization of Two Putative DAHP Synthases of AroG1 and AroG2 and Their Links With Type III Secretion System in Ralstonia solanacearum. Front Microbiol 2019; 10:183. [PMID: 30809210 PMCID: PMC6379268 DOI: 10.3389/fmicb.2019.00183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/23/2019] [Indexed: 11/20/2022] Open
Abstract
Type three secretion system (T3SS) is essential for Ralstonia solanacearum to cause disease in host plants and we previously screened AroG1 as a candidate with impact on the T3SS expression. Here, we focused on two putative DAHP synthases of AroG1 and AroG2, which control the first step of the shikimate pathway, a common route for biosynthesis of aromatic amino acids (AAA), to characterize their functional roles and possible links with virulence in R. solanacearum. Deletion of aroG1/2 or aroG1, but not aroG2, significantly impaired the T3SS expression both in vitro and in planta, and the impact of AroG1 on T3SS was mediated with a well-characterized PrhA signaling cascade. Virulence of the aroG1/2 or aroG1 mutants was completely diminished or significantly impaired in tomato and tobacco plants, but not the aroG2 mutants. The aroG1/2 mutants failed to grow in limited medium, but grew slowly in planta. This significantly impaired growth was also observed in the aroG1 mutants both in planta and limited medium, but not in aroG2 mutants. Complementary aroG1 significantly restored the impaired or diminished bacterial growth, T3SS expression and virulence. Supplementary AAA or shikimic acid, an important intermediate of the shikimate pathway, significantly restored diminished growth in limited medium. The promoter activity assay showed that expression of aroG1 and aroG2 was greatly increased to 10-20-folder higher levels with deletion of the other. All these results demonstrated that both AroG1 and AroG2 are involved in the shikimate pathway and cooperatively essential for AAA biosynthesis in R. solanacearum. The AroG1 plays a major role on bacterial growth, T3SS expression and pathogenicity, while the AroG2 is capable to partially carry out the function of AroG1 in the absence of AroG1.
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Affiliation(s)
- Weiqi Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Jing Li
- The Ninth People's Hospital of Chongqing, Chongqing, China
| | - Xiaojun Shi
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and Biotechnology, Kochi University, Kochi, Japan
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi University, Kochi, Japan
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In Vitro and In Vivo Secretion/Translocation Assays to Identify Novel Ralstonia solanacearum Type 3 Effectors. Methods Mol Biol 2019; 1734:209-222. [PMID: 29288457 DOI: 10.1007/978-1-4939-7604-1_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Phytopathogenic bacteria have evolved multiple strategies to infect plants. Like many gram-negative bacteria, Ralstonia solanacearum, the causal agent of bacterial wilt, possesses a specialized protein secretion machinery to deliver effector proteins directly into the host cells. This type 3 secretion system (T3SS) and the bacterial proteins translocated, called type 3 effectors (T3Es), constitute the main pathogenicity determinants of the R. solanacearum species complex (RSSC). Up to 113 orthologous groups defining T3E genes have been identified among the RSSC strains sequenced to date. The increasing number of R. solanacearum genomic sequences available still expands the number of T3E candidates which require experimental validation. Here, we describe in vitro (type 3 secretion) and in vivo (type 3 translocation based on CyaA' reporter gene) methods to identify and validate type 3-dependent delivery of proteins of interest highlighted as candidate T3Es. We also present protocols to generate dedicated vectors and R. solanacearum transformation to perform these experiments.
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48
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Nakano M, Mukaihara T. Ralstonia solanacearum Type III Effector RipAL Targets Chloroplasts and Induces Jasmonic Acid Production to Suppress Salicylic Acid-Mediated Defense Responses in Plants. PLANT & CELL PHYSIOLOGY 2018; 59:2576-2589. [PMID: 30165674 DOI: 10.1093/pcp/pcy177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/23/2018] [Indexed: 05/06/2023]
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt disease of plants. This pathogen injects more than 70 type III effector proteins called Rips (Ralstonia-injected proteins) into plant cells to succeed in infection. One of the Rips, RipAL, contains a putative lipase domain that shared homology with Arabidopsis DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1). RipAL significantly suppressed pattern-triggered immunity in leaves of Nicotiana benthamiana. Subcellular localization analyses suggest that RipAL localizes to chloroplasts and targets chloroplast lipids in plant cells. Notably, the expression of RipAL markedly increased the jasmonic acid (JA) and JA-isoleucine levels, and induced the expressions of JA-signaling marker genes in plant leaves. Simultaneously, RipAL greatly reduced the salicylic acid (SA) level and decreased the expression levels of SA-signaling marker genes. Mutations in two putative catalytic residues in the DAD1-like lipase domain abolished the ability of RipAL to induce JA production and suppress SA signaling. Infection of R. solanacearum also induced JA production and simultaneously decreased the SA level in susceptible pepper leaves in a ripAL-dependent manner. The growth of R. solanacearum enhanced in plants with silenced CaICS1, which encodes the SA synthesis enzyme isochorismate synthase 1. These results indicate that SA signaling is involved in the defense response against R. solanacearum and that R. solanacearum uses RipAL to induce JA production and suppress SA signaling in plant cells.
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Affiliation(s)
- Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama, Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama, Japan
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49
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Ombiro GS, Sawai T, Noutoshi Y, Nishina Y, Matsui H, Yamamoto M, Toyoda K, Ichinose Y. Specific growth inhibitors of Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, and Clavibacter michiganensis subsp. michiganensis. Microbiol Res 2018; 215:29-35. [DOI: 10.1016/j.micres.2018.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/28/2018] [Accepted: 06/09/2018] [Indexed: 11/26/2022]
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Asolkar T, Ramesh R. Development of T3SS Mutants ( hrpB- and hrcV-) of Ralstonia solanacearum, Evaluation of Virulence Attenuation in Brinjal and Tomato-A Pre-requisite to Validate T3Es of R. solanacearum. Indian J Microbiol 2018; 58:372-380. [PMID: 30013282 PMCID: PMC6023813 DOI: 10.1007/s12088-018-0736-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 04/23/2018] [Indexed: 11/27/2022] Open
Abstract
Ralstonia solanacearum is an important plant pathogen which infects a large number of agriculturally important crops. The Type Three Secretion System (T3SS) plays a major role in its pathogenicity by secreting type III effectors (T3Es) which overthrow the host defence mechanism. The secretion of T3Es is transcriptionally regulated by hrpB and its secretion is dependent on the pili formed by hrcV gene. In this study, two T3SS mutants of R. solanacearum strain Rs-09-161 viz. Rs-HrpB- and Rs-HrcV- were developed through insertional mutagenesis. The method of development of insertional mutant is quite simple and reliable. The plasmid integrates through homologous recombination and in vitro studies have proved that the integration was stable for several generations. The mutants are non-pathogenic on its highly susceptible hosts, brinjal and tomato inoculated by soil drench method and by petiole inoculation directly into the vascular system. Further it was observed that the colonisation ability of the mutants was also highly reduced in the susceptible host. These mutants will be useful in validating putative T3E through translocation studies.
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Affiliation(s)
- Trupti Asolkar
- ICAR-Central Coastal Agricultural Research Institute, Old Goa, Goa 403402 India
- Department of Microbiology, Goa University, Taleigao Plateau, Goa 403206 India
| | - Raman Ramesh
- ICAR-Central Coastal Agricultural Research Institute, Old Goa, Goa 403402 India
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