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Gallas N, Li X, von Roepenack‐Lahaye E, Schandry N, Jiang Y, Wu D, Lahaye T. An ancient cis-element targeted by Ralstonia solanacearum TALE-like effectors facilitates the development of a promoter trap that could confer broad-spectrum wilt resistance. Plant Biotechnol J 2024; 22:602-616. [PMID: 37870975 PMCID: PMC10893940 DOI: 10.1111/pbi.14208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/25/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
Ralstonia solanacearum, a species complex of bacterial plant pathogens that causes bacterial wilt, comprises four phylotypes that evolved when a founder population was split during the continental drift ~180 million years ago. Each phylotype contains strains with RipTAL proteins structurally related to transcription activator-like (TAL) effectors from the bacterial pathogen Xanthomonas. RipTALs have evolved in geographically separated phylotypes and therefore differ in sequence and potentially functionality. Earlier work has shown that phylotype I RipTAL Brg11 targets a 17-nucleotide effector binding element (EBE) and transcriptionally activates the downstream arginine decarboxylase (ADC) gene. The predicted DNA binding preferences of Brg11 and RipTALs from other phylotypes are similar, suggesting that most, if not all, RipTALs target the Brg11-EBE motif and activate downstream ADC genes. Here we show that not only phylotype I RipTAL Brg11 but also RipTALs from other phylotypes activate host genes when preceded by the Brg11-EBE motif. Furthermore, we show that Brg11 and RipTALs from other phylotypes induce the same quantitative changes of ADC-dependent plant metabolites, suggesting that most, if not all, RipTALs induce functionally equivalent changes in host cells. Finally, we report transgenic tobacco lines in which the RipTAL-binding motif Brg11-EBE mediates RipTAL-dependent transcription of the executor-type resistance (R) gene Bs4C from pepper, thereby conferring resistance to RipTAL-delivering R. solanacearum strains. Our results suggest that cell death-inducing executor-type R genes, preceded by the RipTAL-binding motif Brg11-EBE, could be used to genetically engineer broad-spectrum bacterial wilt resistance in crop plants without any apparent fitness penalty.
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Affiliation(s)
- Niels Gallas
- Allgemeine Genetik, Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
| | - Xiaoxu Li
- Technology Center, China Tobacco Hunan Industrial Co., Ltd.ChangshaChina
- Present address:
Beijing Life Science AcademyBeijingChina
| | - Edda von Roepenack‐Lahaye
- Analytik‐Zentrale Einheiten, Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
| | - Niklas Schandry
- Genetics, Department of BiologyLudwig‐Maximilians‐University MunichMartinsriedGermany
| | - Yuxin Jiang
- Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of BiologyHunan UniversityChangshaChina
| | - Dousheng Wu
- Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of BiologyHunan UniversityChangshaChina
| | - Thomas Lahaye
- Allgemeine Genetik, Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenTübingenGermany
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2
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Yang L, Wang Y, Liang Y, Deng H, Wang J, Dai Y, Guo F, Zhou H, Li S, Ding W. pH-responsive bentonite nanoclay carriers control the release of benzothiazolinone to restrain bacterial wilt disease. Pestic Biochem Physiol 2024; 198:105754. [PMID: 38225096 DOI: 10.1016/j.pestbp.2023.105754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 01/17/2024]
Abstract
Ralstonia solanacearum (R. solanacearum) is one of the most devastating pathogens in terms of losses in agricultural production. Bentonite (Bent) is a promising synergistic agent used in development of effective and environmentally friendly pesticides against plant disease. However, the synergistic mechanism of Bent nanoclays with benzothiazolinone (BIT) against R. solanacearum is unknown. In this work, acid-functionalized porous Bent and cetyltrimethylammonium bromide (CTAB) were employed as the core nanoclays, and BIT was loaded into the clay to form BIT-loaded CT-Bent (BIT@CT-Bent) for the control of bacterial wilt disease. BIT@CT-Bent exhibited pH-responsive release behavior that fit the Fickian diffusion model, rapidly releasing BIT in an acidic environment (pH = 5.5). The antibacterial effect of BIT@CT-Bent was approximately 4 times greater than that of the commercial product BIT, and its biotoxicity was much lower than that of BIT under the same conditions. Interestingly, R. solanacearum attracted BIT@CT-Bent into the nanocomposites and induced cytoplasmic leakage and changes in membrane permeability, indicating an efficient and synergistic bactericidal effect that rapidly reduced bacterial density. In addition, BIT@CT-Bent significantly inhibited R. solanacearum biofilm formation and swimming activity, by suppressing the expression of phcA, solR and vsrC. Indeed, exogenous application of BIT@CT-Bent significantly suppressed the virulence of R. solanacearum on tobacco plants, with control effect of 75.48%, 72.08% and 66.08% at 9, 11 and 13 days after inoculation, respectively. This study highlights the potential of using BIT@CT-Bent as an effective, eco-friendly bactericide to control bacterial wilt diseases and for the development of sustainable crop protection strategies.
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Affiliation(s)
- Liang Yang
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Yao Wang
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Yijia Liang
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Haibin Deng
- Guangdong Tobacco Research Institute, Guangdong 512026, China
| | - Jun Wang
- Guangdong Tobacco Research Institute, Guangdong 512026, China
| | - Yuhao Dai
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Fuyou Guo
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Hong Zhou
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Shili Li
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Wei Ding
- Laboratory of Natural Products Pesticides, College of Plant Protection, Southwest University, Chongqing 400715, China.
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Si X, Liu H, Cheng X, Xu C, Han Z, Dai Z, Wang R, Pan C, Lu G. Integrative transcriptomic analysis unveils lncRNA-miRNA-mRNA interplay in tomato plants responding to Ralstonia solanacearum. Int J Biol Macromol 2023; 253:126891. [PMID: 37709224 DOI: 10.1016/j.ijbiomac.2023.126891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/26/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023]
Abstract
Ralstonia solanacearum, a bacterial plant pathogen, poses a significant threat to tomato (Solanum lycopersicum) production through destructive wilt disease. While noncoding RNA has emerged as a crucial regulator in plant disease, its specific involvement in tomato bacterial wilt remains limited. Here, we conducted a comprehensive analysis of the transcriptional landscape, encompassing both mRNAs and noncoding RNAs, in a tomato resistant line ('ZRS_7') and a susceptible line ('HTY_9') upon R. solanacearum inoculation using high-throughput RNA sequencing. Differential expression (DE) analysis revealed significant alterations in 7506 mRNAs, 997 lncRNAs, and 69 miRNAs between 'ZRS_7' and 'HTY_9' after pathogen exposure. Notably, 4548 mRNAs, 367 lncRNAs, and 26 miRNAs exhibited genotype-specific responses to R. solanacearum inoculation. GO and KEGG pathway analyses unveiled the potential involvement of noncoding RNAs in the response to bacterial wilt disease, targeting receptor-like kinases, cell wall-related genes, glutamate decarboxylases, and other key pathways. Furthermore, we constructed a comprehensive competing endogenous RNA (ceRNA) network incorporating 13 DE-miRNAs, 30 DE-lncRNAs, and 127 DEGs, providing insights into their potential contributions to the response against bacterial inoculation. Importantly, the characterization of possible endogenous target mimics (eTMs) of Sly-miR482e-3p via VIGS technology demonstrated the significant impact of eTM482e-3p-1 silencing on tomato's sensitivity to R. solanacearum. These findings support the existence of an eTM482e-3p-1-Sly-miR482e-3p-NBS-LRRs network in regulating tomato's response to the pathogen. Collectively, our findings shed light on the intricate interactions among lncRNAs, miRNAs, and mRNAs as underlying factors in conferring resistance to R. solanacearum in tomato.
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Affiliation(s)
- Xiuyang Si
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Hongyan Liu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Xi Cheng
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Chengcui Xu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Zhanghui Han
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Zhongren Dai
- Branch Academy of Horticultural Research, Harbin Academy of Agricultural Sciences, Harbin 150029, China
| | - Rongqing Wang
- Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou 310022, China
| | - Changtian Pan
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agricultural, Zhejiang University, Hangzhou 310058, China
| | - Gang Lu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agricultural, Zhejiang University, Hangzhou 310058, China.
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Xu A, Wei L, Ke J, Peng C, Li P, Fan C, Yu X, Li B. ETI signaling nodes are involved in resistance of Hawaii 7996 to Ralstonia solanacearum-induced bacterial wilt disease in tomato. Plant Signal Behav 2023; 18:2194747. [PMID: 36994774 PMCID: PMC10072054 DOI: 10.1080/15592324.2023.2194747] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
Bacterial wilt caused by the soil-borne pathogen Ralstonia solanacearum is a destructive disease of tomato. Tomato cultivar Hawaii 7996 is well-known for its stable resistance against R. solanacearum. However, the resistance mechanism of Hawaii 7996 has not yet been revealed. Here, we showed that Hawaii 7996 activated root cell death response and exhibited stronger defense gene induction than the susceptible cultivar Moneymaker after R. solanacearum GMI1000 infection. By employing virus-induced gene silencing (VIGS) and CRISPR/Cas9 technologies, we found that SlNRG1-silenced and SlADR1-silenced/knockout mutant tomato partially or completely lost resistance to bacterial wilt, indicating that helper NLRs SlADR1 and SlNRG1, the key nodes of effector-triggered immunity (ETI) pathways, are required for Hawaii 7996 resistance. In addition, while SlNDR1 was dispensable for the resistance of Hawaii 7996 to R. solanacearum, SlEDS1, SlSAG101a/b, and SlPAD4 were essential for the immune signaling pathways in Hawaii 7996. Overall, our results suggested that robust resistance of Hawaii 7996 to R. solanacearum relied on the involvement of multiple conserved key nodes of the ETI signaling pathways. This study sheds light on the molecular mechanisms underlying tomato resistance to R. solanacearum and will accelerate the breeding of tomatoes resilient to diseases.
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Affiliation(s)
- Ai Xu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Lan Wei
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Jingjing Ke
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Chengfeng Peng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Pengyue Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Changqiu Fan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Xiao Yu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Bo Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
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5
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de Pedro-Jové R, Corral J, Rocafort M, Puigvert M, Azam FL, Vandecaveye A, Macho AP, Balsalobre C, Coll NS, Orellano E, Valls M. Gene expression changes throughout the life cycle allow a bacterial plant pathogen to persist in diverse environmental habitats. PLoS Pathog 2023; 19:e1011888. [PMID: 38113281 PMCID: PMC10763947 DOI: 10.1371/journal.ppat.1011888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/03/2024] [Accepted: 12/07/2023] [Indexed: 12/21/2023] Open
Abstract
Bacterial pathogens exhibit a remarkable ability to persist and thrive in diverse ecological niches. Understanding the mechanisms enabling their transition between habitats is crucial to control dissemination and potential disease outbreaks. Here, we use Ralstonia solanacearum, the causing agent of the bacterial wilt disease, as a model to investigate pathogen adaptation to water and soil, two environments that act as bacterial reservoirs, and compare this information with gene expression in planta. Gene expression in water resembled that observed during late xylem colonization, with an intriguing induction of the type 3 secretion system (T3SS). Alkaline pH and nutrient scarcity-conditions also encountered during late infection stages-were identified as the triggers for this T3SS induction. In the soil environment, R. solanacearum upregulated stress-responses and genes for the use of alternate carbon sources, such as phenylacetate catabolism and the glyoxylate cycle, and downregulated virulence-associated genes. We proved through gain- and loss-of-function experiments that genes associated with the oxidative stress response, such as the regulator OxyR and the catalase KatG, are key for bacterial survival in soil, as their deletion cause a decrease in culturability associated with a premature induction of the viable but non culturable state (VBNC). This work identifies essential factors necessary for R. solanacearum to complete its life cycle and is the first comprehensive gene expression analysis in all environments occupied by a bacterial plant pathogen, providing valuable insights into its biology and adaptation to unexplored habitats.
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Affiliation(s)
- Roger de Pedro-Jové
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Jordi Corral
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Mercedes Rocafort
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Marina Puigvert
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Fàtima Latif Azam
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Agustina Vandecaveye
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-UNR-CONICET), Rosario, Santa Fe, Argentina
| | - Alberto P. Macho
- Shanghai Centre for Plant Stress Biology, CAS Centre for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Carlos Balsalobre
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Elena Orellano
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (IBR-UNR-CONICET), Rosario, Santa Fe, Argentina
| | - Marc Valls
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
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6
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Li X, Yin W, Lin JD, Zhang Y, Guo Q, Wang G, Chen X, Cui B, Wang M, Chen M, Li P, He YW, Qian W, Luo H, Zhang LH, Liu XW, Song S, Deng Y. Regulation of the physiology and virulence of Ralstonia solanacearum by the second messenger 2',3'-cyclic guanosine monophosphate. Nat Commun 2023; 14:7654. [PMID: 37996405 PMCID: PMC10667535 DOI: 10.1038/s41467-023-43461-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
Previous studies have demonstrated that bis-(3',5')-cyclic diguanosine monophosphate (bis-3',5'-c-di-GMP) is a ubiquitous second messenger employed by bacteria. Here, we report that 2',3'-cyclic guanosine monophosphate (2',3'-cGMP) controls the important biological functions, quorum sensing (QS) signaling systems and virulence in Ralstonia solanacearum through the transcriptional regulator RSp0980. This signal specifically binds to RSp0980 with high affinity and thus abolishes the interaction between RSp0980 and the promoters of target genes. In-frame deletion of RSp0334, which contains an evolved GGDEF domain with a LLARLGGDQF motif required to catalyze 2',3'-cGMP to (2',5')(3',5')-cyclic diguanosine monophosphate (2',3'-c-di-GMP), altered the abovementioned important phenotypes through increasing the intracellular 2',3'-cGMP levels. Furthermore, we found that 2',3'-cGMP, its receptor and the evolved GGDEF domain with a LLARLGGDEF motif also exist in the human pathogen Salmonella typhimurium. Together, our work provides insights into the unusual function of the GGDEF domain of RSp0334 and the special regulatory mechanism of 2',3'-cGMP signal in bacteria.
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Affiliation(s)
- Xia Li
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Wenfang Yin
- Integrative Microbiology Research Center, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Junjie Desmond Lin
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Quan Guo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Gerun Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Xiayu Chen
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Binbin Cui
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Mingfang Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Min Chen
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Peng Li
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, China
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institution of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Haibin Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Lian-Hui Zhang
- Integrative Microbiology Research Center, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Xue-Wei Liu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Shihao Song
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China.
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China.
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Kim B, Yu W, Kim H, Dong Q, Choi S, Prokchorchick M, Macho AP, Sohn KH, Segonzac C. A plasma membrane nucleotide-binding leucine-rich repeat receptor mediates the recognition of the Ralstonia pseudosolanacearum effector RipY in Nicotiana benthamiana. Plant Commun 2023; 4:100640. [PMID: 37349986 PMCID: PMC10721487 DOI: 10.1016/j.xplc.2023.100640] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 06/01/2023] [Accepted: 06/18/2023] [Indexed: 06/24/2023]
Abstract
Bacterial wilt disease caused by several Ralstonia species is one of the most destructive diseases in Solanaceae crops. Only a few functional resistance genes against bacterial wilt have been cloned to date. Here, we show that the broadly conserved type III secreted effector RipY is recognized by the Nicotiana benthamiana immune system, leading to cell death induction, induction of defense-related gene expression, and restriction of bacterial pathogen growth. Using a multiplexed virus-induced gene-silencing-based N. benthamiana nucleotide-binding and leucine-rich repeat receptor (NbNLR) library, we identified a coiled-coil (CC) nucleotide-binding and leucine-rich repeat receptor (CNL) required for recognition of RipY, which we named RESISTANCE TO RALSTONIA SOLANACEARUM RIPY (RRS-Y). Genetic complementation assays in RRS-Y-silenced plants and stable rrs-y knockout mutants demonstrated that RRS-Y is sufficient to activate RipY-induced cell death and RipY-induced immunity to Ralstonia pseudosolanacearum. RRS-Y function is dependent on the phosphate-binding loop motif of the nucleotide-binding domain but independent of the characterized signaling components ENHANCED DISEASE SUSCEPTIBILITY 1, ACTIVATED DISEASE RESISTANCE 1, and N REQUIREMENT GENE 1 and the NLR helpers NB-LRR REQUIRED FOR HR-ASSOCIATED CELL DEATH-2, -3, and -4 in N. benthamiana. We further show that RRS-Y localization at the plasma membrane is mediated by two cysteine residues in the CC domain and is required for RipY recognition. RRS-Y also broadly recognizes RipY homologs across Ralstonia species. Lastly, we show that the C-terminal region of RipY is indispensable for RRS-Y activation. Together, our findings provide an additional effector/receptor pair system to deepen our understanding of CNL activation in plants.
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Affiliation(s)
- Boyoung Kim
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Republic of Korea; Plant Immunity Research Center, Seoul National University, Seoul 08826, Republic of Korea
| | - Wenjia Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Haseong Kim
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Republic of Korea; Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Qian Dong
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Sera Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Maxim Prokchorchick
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Alberto P Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Kee Hoon Sohn
- Plant Immunity Research Center, Seoul National University, Seoul 08826, Republic of Korea; Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea
| | - Cécile Segonzac
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Republic of Korea; Plant Immunity Research Center, Seoul National University, Seoul 08826, Republic of Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Republic of Korea; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Deng Q, Liu H, Lu Q, Gangurde SS, Du P, Li H, Li S, Liu H, Wang R, Huang L, Chen R, Fan C, Liang X, Chen X, Hong Y. Silicon Application for the Modulation of Rhizosphere Soil Bacterial Community Structures and Metabolite Profiles in Peanut under Ralstonia solanacearum Inoculation. Int J Mol Sci 2023; 24:ijms24043268. [PMID: 36834682 PMCID: PMC9960962 DOI: 10.3390/ijms24043268] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 02/11/2023] Open
Abstract
Silicon (Si) has been shown to promote peanut growth and yield, but whether Si can enhance the resistance against peanut bacterial wilt (PBW) caused by Ralstonia solanacearum, identified as a soil-borne pathogen, is still unclear. A question regarding whether Si enhances the resistance of PBW is still unclear. Here, an in vitro R. solanacearum inoculation experiment was conducted to study the effects of Si application on the disease severity and phenotype of peanuts, as well as the microbial ecology of the rhizosphere. Results revealed that Si treatment significantly reduced the disease rate, with a decrement PBW severity of 37.50% as compared to non-Si treatment. The soil available Si (ASi) significantly increased by 13.62-44.87%, and catalase activity improved by 3.01-3.10%, which displayed obvious discrimination between non-Si and Si treatments. Furthermore, the rhizosphere soil bacterial community structures and metabolite profiles dramatically changed under Si treatment. Three significantly changed bacterial taxa were observed, which showed significant abundance under Si treatment, whereas the genus Ralstonia genus was significantly suppressed by Si. Similarly, nine differential metabolites were identified to involve into unsaturated fatty acids via a biosynthesis pathway. Significant correlations were also displayed between soil physiochemical properties and enzymes, the bacterial community, and the differential metabolites by pairwise comparisons. Overall, this study reports that Si application mediated the evolution of soil physicochemical properties, the bacterial community, and metabolite profiles in the soil rhizosphere, which significantly affects the colonization of the Ralstonia genus and provides a new theoretical basis for Si application in PBW prevention.
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Affiliation(s)
- Quanqing Deng
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Hao Liu
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Qing Lu
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Sunil S. Gangurde
- Department of Plant Pathology, University of Georgia, Tifton, GA 30602, USA
| | - Puxuan Du
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Haifen Li
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Shaoxiong Li
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Haiyan Liu
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Runfeng Wang
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Lu Huang
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Ronghua Chen
- Institute of Agricultural Sciences in Ganzhou, Ganzhou 341000, China
| | - Chenggen Fan
- Institute of Agricultural Sciences in Ganzhou, Ganzhou 341000, China
| | - Xuanqiang Liang
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Xiaoping Chen
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Correspondence: (X.C.); (Y.H.)
| | - Yanbin Hong
- Guangdong Provincial Key Laboratory of Crop Genetic Improvement, South China Peanut Sub-Center of National Center of Oilseed Crops Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Correspondence: (X.C.); (Y.H.)
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10
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Inoue K, Takemura C, Senuma W, Maeda H, Kai K, Kiba A, Ohnishi K, Tsuzuki M, Hikichi Y. The behavior of Ralstonia pseudosolanacearum strain OE1-1 and morphological changes of cells in tomato roots. J Plant Res 2023; 136:19-31. [PMID: 36427093 DOI: 10.1007/s10265-022-01427-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
The soil-borne Gram-negative β-proteobacterium Ralstonia solanacearum species complex (RSSC) infects tomato roots through the wounds where secondary roots emerge, infecting xylem vessels. Because it is difficult to observe the behavior of RSSC by a fluorescence-based microscopic approach at high magnification, we have little information on its behavior at the root apexes in tomato roots. To analyze the infection route of a strain of phylotype I of RSSC, R. pseudosolanacearum strain OE1-1, which invades tomato roots through the root apexes, we first developed an in vitro pathosystem using 4 day-old-tomato seedlings without secondary roots co-incubated with the strain OE1-1. The microscopic observation of toluidine blue-stained longitudinal semi-thin resin sections of tomato roots allowed to detect attachment of the strain OE1-1 to surfaces of the meristematic and elongation zones in tomato roots. We then observed colonization of OE1-1 in intercellular spaces between epidermis and cortex in the elongation zone, and a detached epidermis in the elongation zone. Furthermore, we observed cortical and endodermal cells without a nucleus and with the cell membrane pulling away from the cell wall. The strain OE1-1 next invaded cell wall-degenerated cortical cells and formed mushroom-shaped biofilms to progress through intercellular spaces of the cortex and endodermis, infecting pericycle cells and xylem vessels. The deletion of egl encoding β-1,4-endoglucanase, which is one of quorum sensing (QS)-inducible plant cell wall-degrading enzymes (PCDWEs) secreted via the type II secretion system (T2SS) led to a reduced infectivity in cortical cells. Furthermore, the QS-deficient and T2SS-deficient mutants lost their infectivity in cortical cells and the following infection in xylem vessels. Taking together, infection of OE1-1, which attaches to surfaces of the meristematic and elongation zones, in cortical cells of the elongation zone in tomato roots, dependently on QS-inducible PCDWEs secreted via the T2SS, leads to its subsequent infection in xylem vessels.
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Affiliation(s)
- Kanako Inoue
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Japan
| | - Chika Takemura
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Nankoku, Kochi, Japan
| | - Wakana Senuma
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Nankoku, Kochi, Japan
| | - Hidefumi Maeda
- Faculty of Advanced Science and Technology, Ryukoku University, Otsu, Japan
| | - Kenji Kai
- Graduate School of Agriculture, Osaka Metropolitan University, Sakai, Japan
| | - Akinori Kiba
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Nankoku, Kochi, Japan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Nankoku, Kochi, Japan
| | - Masayuki Tsuzuki
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Nankoku, Kochi, Japan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, 783-8502, Nankoku, Kochi, Japan.
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11
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Qi P, Huang M, Hu X, Zhang Y, Wang Y, Li P, Chen S, Zhang D, Cao S, Zhu W, Xie J, Cheng J, Fu Y, Jiang D, Yu X, Li B. A Ralstonia solanacearum effector targets TGA transcription factors to subvert salicylic acid signaling. Plant Cell 2022; 34:1666-1683. [PMID: 35043960 PMCID: PMC9048914 DOI: 10.1093/plcell/koac015] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 01/13/2022] [Indexed: 05/25/2023]
Abstract
The bacterial pathogen Ralstonia solanacearum causes wilt disease on Arabidopsis thaliana and tomato (Solanum lycopersicum). This pathogen uses type III effectors to inhibit the plant immune system; however, how individual effectors interfere with plant immune responses, including transcriptional reprograming, remain elusive. Here, we show that the type III effector RipAB targets Arabidopsis TGACG SEQUENCE-SPECIFIC BINDING PROTEIN (TGA) transcription factors, the central regulators of plant immune gene regulation, via physical interaction in the nucleus to dampen immune responses. RipAB was required for R. solanacearum virulence on wild-type tomato and Arabidopsis but not Arabidopsis tga1 tga4 and tga2 tga5 tga6 mutants. Stable expression of RipAB in Arabidopsis suppressed the pathogen-associated molecular pattern-triggered reactive oxygen species (ROS) burst and immune gene induction as well as salicylic acid (SA) regulons including RBOHD and RBOHF, responsible for ROS production, all of which were phenocopied by the tga1 tga4 and tga2 tga5 tga6 mutants. We found that TGAs directly activate RBOHD and RBOHF expression and that RipAB inhibits this through interfering with the recruitment of RNA polymerase II. These results suggest that TGAs are the bona fide and major virulence targets of RipAB, which disrupts SA signaling by inhibiting TGA activity to achieve successful infection.
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Affiliation(s)
| | | | | | - Ying Zhang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Ying Wang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Pengyue Li
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Shiyun Chen
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dan Zhang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Sen Cao
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Wanting Zhu
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yanping Fu
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiao Yu
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory Wuhan, Hubei, China
- Hubei Key Lab of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Bo Li
- Author for correspondence:
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12
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Takemura C, Senuma W, Hayashi K, Minami A, Terazawa Y, Kaneoka C, Sakata M, Chen M, Zhang Y, Nobori T, Sato M, Kiba A, Ohnishi K, Tsuda K, Kai K, Hikichi Y. PhcQ mainly contributes to the regulation of quorum sensing-dependent genes, in which PhcR is partially involved, in Ralstonia pseudosolanacearum strain OE1-1. Mol Plant Pathol 2021; 22:1538-1552. [PMID: 34423519 PMCID: PMC8578825 DOI: 10.1111/mpp.13124] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 05/29/2023]
Abstract
The gram-negative plant-pathogenic β-proteobacterium Ralstonia pseudosolanacearum strain OE1-1 produces methyl 3-hydroxymyristate as a quorum sensing (QS) signal via the methyltransferase PhcB and senses the chemical through the sensor histidine kinase PhcS. This leads to functionalization of the LysR family transcriptional regulator PhcA, regulating QS-dependent genes responsible for the QS-dependent phenotypes including virulence. The phc operon consists of phcB, phcS, phcR, and phcQ, with the latter two encoding regulator proteins with a receiver domain and a histidine kinase domain and with a receiver domain, respectively. To elucidate the function of PhcR and PhcQ in the regulation of QS-dependent genes, we generated phcR-deletion and phcQ-deletion mutants. Though the QS-dependent phenotypes of the phcR-deletion mutant were largely unchanged, deletion of phcQ led to a significant change in the QS-dependent phenotypes. Transcriptome analysis coupled with quantitative reverse transcription-PCR and RNA-sequencing revealed that phcB, phcK, and phcA in the phcR-deletion and phcQ-deletion mutants were expressed at similar levels as in strain OE1-1. Compared with strain OE1-1, expression of 22.9% and 26.4% of positively and negatively QS-dependent genes, respectively, was significantly altered in the phcR-deletion mutant. However, expression of 96.8% and 66.9% of positively and negatively QS-dependent genes, respectively, was significantly altered in the phcQ-deletion mutant. Furthermore, a strong positive correlation of expression of these QS-dependent genes was observed between the phcQ-deletion and phcA-deletion mutants. Our results indicate that PhcQ mainly contributes to the regulation of QS-dependent genes, in which PhcR is partially involved.
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Affiliation(s)
- Chika Takemura
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Wakana Senuma
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
- Present address:
Central Research InstituteIshihara Sangyo Kaisha, LTD.KusatsuShigaJapan
| | - Kazusa Hayashi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
- Present address:
Agriculture Research CenterKochi PrefecturalNankokuJapan
| | - Ayaka Minami
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Yuki Terazawa
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Chisaki Kaneoka
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiJapan
| | - Megumi Sakata
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiJapan
| | - Min Chen
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Yong Zhang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River BasinSouthwest UniversityChongqingChina
| | - Tatsuya Nobori
- Salk Institute for Biological StudiesLa JollaCaliforniaUSA
| | - Masanao Sato
- Graduate School of AgricultureHokkaido UniversitySapporoJapan
| | - Akinori Kiba
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Kenichi Tsuda
- State Key Laboratory of Agricultural Microbiology, Interdisciplinary Sciences Research Institute, College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanChina
| | - Kenji Kai
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiJapan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
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13
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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. Mol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Yang S, Zhang Y, Cai W, Liu C, Hu J, Shen L, Huang X, Guan D, He S. CaWRKY28 Cys249 is Required for Interaction with CaWRKY40 in the Regulation of Pepper Immunity to Ralstonia solanacearum. Mol Plant Microbe Interact 2021; 34:733-745. [PMID: 33555219 DOI: 10.1094/mpmi-12-20-0361-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
WRKY transcription factors have been implicated in plant response to pathogens but how WRKY-mediated networks are organized and operate to produce appropriate transcriptional outputs remains largely unclear. Here, we identify a member of the WRKY family from pepper (Capsicum annuum), CaWRKY28, that physically interacts with CaWRKY40, a positive regulator of pepper immunity and thermotolerance. We confirmed CaWRKY28-CaWRKY40 interaction by coimmunoprecipitation, bimolecular fluorescence complementation, and microscale thermophoresis. Our findings supported the idea that CaWRKY28 is a nuclear protein that acts as positive regulator in pepper responses to infection by the pathogenic bacterium Ralstonia solanacearum. It performs its function not by directly modulating the W-box containing immunity-related genes but by promoting CaWRKY40 via physical interaction to bind and activate its immunity-related target genes, including CaPR1, CaNPR1, CaDEF1, and CaABR1, but not its thermotolerance-related target gene, CaHSP24. All of these data indicate that CaWRKY28 interacts with and potentiates CaWRKY40 in regulating immunity against R. solanacearum infection but not thermotolerance. Importantly, we discovered that CaWRKY28 Cys249, shared by CaWRKY28 and its orthologs probably only in the family Solanaceae, is crucial for the CaWRKY28-CaWRKY40 interaction. These results highlight how CaWRKY28 associates with CaWRKY40 during the establishment of WRKY networks, and how CaWRKY40 achieves its functional specificity during pepper responses to R. solanacearum infection.[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)
- Sheng Yang
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Yangwen Zhang
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Weiwei Cai
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Cailing Liu
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Jiong Hu
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Lei Shen
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Xueying Huang
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Deyi Guan
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
| | - Shuilin He
- National Education Ministry Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
- Key Laboratory of Applied Genetics of universities in Fujian Province, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
- Agricultural College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China
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15
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Nakahara H, Mori K, Mori T, Matsuzoe N. Induction of spontaneous phenotype conversion in Ralstonia solanacearum by addition of iron compounds in liquid medium. J Microbiol Methods 2021; 186:106233. [PMID: 33965508 DOI: 10.1016/j.mimet.2021.106233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 11/19/2022]
Abstract
Ralstonia solanacearum is a soil-borne pathogen that causes bacterial wilt in plants. The wild-type strain of R. solanacearum undergoes spontaneous phenotype conversion (PC), from a fluidal to non-fluidal colony morphology. PC mutants are non-pathogenic due to reduced virulence factors, and can control wilt diseases as biological control agents. The induction factors of PC in R. solanacearum are currently unclear. Here, we investigated the effect of iron treatment on bacterial growth of wild-type strain and PC mutant, and PC of the wild-type strain in liquid medium. Interestingly, PC was frequently induced in the single cultured wild-type strain by iron treatment; however, PC was not induced in the co-culture. In a co-culture of both strains, the PC mutant showed increased growth compared to the wild-type strain by iron treatment. Furthermore, we investigated the effects of iron treatment on the bacterial growth and PC of the wild-type strain under different culture conditions of medium type (MM broth, BG broth, and water medium), iron compounds, and pH. In BG broth, PC occurred frequently regardless of iron treatment. In MM broth, the optimal conditions for high frequency induction of PC by iron treatments were treatment of iron (III) EDTA, and under pH 7-8. Conversely, PC was not induced by iron treatment in water medium and in MM broth under pH 5 conditions. Common to the culture conditions wherein PC was not induced by iron treatment, the bacterial density of the wild-type strain was as low as 106 CFU mL-1 or less. Finally, we investigated the effects on bacterial growth and PC of the wild-type strain by the iron treatment and addition of culture filtrate after cultivation of the wild-type strain at high concentration. In medium containing only the culture filtrate, PC did not occur. However, in medium containing the culture filtrate and iron, PC occurred frequently. Our results thus suggest that high-density growth of the wild-type strain as well as the presence of iron are involved in inducing PC in R. solanacearum.
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Affiliation(s)
- Hiroki Nakahara
- Arid Land Research Center, Tottori University, Hamasaka 1390, Tottori 680-0001, Japan.
| | - Kento Mori
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Tsukide 3-1-100, Higashi-ku, Kumamoto 862-8502, Japan
| | - Taro Mori
- Faculty of Education, Shiga University, Hiratsu 2-5-1, Otsu, Shiga 520-0862, Japan
| | - Naotaka Matsuzoe
- Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Tsukide 3-1-100, Higashi-ku, Kumamoto 862-8502, Japan
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16
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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17
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Xian L, Yu G, Wei Y, Rufian JS, Li Y, Zhuang H, Xue H, Morcillo RJL, Macho AP. A Bacterial Effector Protein Hijacks Plant Metabolism to Support Pathogen Nutrition. Cell Host Microbe 2020; 28:548-557.e7. [PMID: 32735848 DOI: 10.1016/j.chom.2020.07.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 04/23/2020] [Accepted: 06/30/2020] [Indexed: 01/01/2023]
Abstract
Many bacterial plant pathogens employ a type III secretion system to inject effector proteins within plant cells to suppress plant immunity. Whether and how effector proteins also co-opt plant metabolism to support extensive bacterial replication remains an open question. Here, we show that Ralstonia solanacearum, the causal agent of bacterial wilt disease, secretes the effector protein RipI, which interacts with plant glutamate decarboxylases (GADs) to alter plant metabolism and support bacterial growth. GADs are activated by calmodulin and catalyze the biosynthesis of gamma-aminobutyric acid (GABA), an important signaling molecule in plants and animals. RipI promotes the interaction of GADs with calmodulin, enhancing the production of GABA. R. solanacearum is able to replicate efficiently using GABA as a nutrient, and both RipI and plant GABA contribute to a successful infection. This work reveals a pathogenic strategy to hijack plant metabolism for the biosynthesis of nutrients that support microbial growth during plant colonization.
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Affiliation(s)
- Liu Xian
- 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 100049, China
| | - 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
| | - 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 100049, China
| | - Jose S Rufian
- 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
| | - Yansha Li
- 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
| | - 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
| | - Hao Xue
- 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 100049, China
| | - Rafael J L Morcillo
- 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
| | - 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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18
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Yu G, Xian L, Xue H, Yu W, Rufian JS, Sang Y, Morcillo RJL, Wang Y, Macho AP. A bacterial effector protein prevents MAPK-mediated phosphorylation of SGT1 to suppress plant immunity. PLoS Pathog 2020; 16:e1008933. [PMID: 32976518 PMCID: PMC7540872 DOI: 10.1371/journal.ppat.1008933] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 10/07/2020] [Accepted: 08/27/2020] [Indexed: 11/23/2022] Open
Abstract
Nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins function as sensors that perceive pathogen molecules and activate immunity. In plants, the accumulation and activation of NLRs is regulated by SUPPRESSOR OF G2 ALLELE OF skp1 (SGT1). In this work, we found that an effector protein named RipAC, secreted by the plant pathogen Ralstonia solanacearum, associates with SGT1 to suppress NLR-mediated SGT1-dependent immune responses, including those triggered by another R. solanacearum effector, RipE1. RipAC does not affect the accumulation of SGT1 or NLRs, or their interaction. However, RipAC inhibits the interaction between SGT1 and MAP kinases, and the phosphorylation of a MAPK target motif in the C-terminal domain of SGT1. Such phosphorylation is enhanced upon activation of immune signaling and contributes to the activation of immune responses mediated by the NLR RPS2. Additionally, SGT1 phosphorylation contributes to resistance against R. solanacearum. Our results shed light onto the mechanism of activation of NLR-mediated immunity, and suggest a positive feedback loop between MAPK activation and SGT1-dependent NLR activation.
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Affiliation(s)
- Gang Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Liu Xian
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hao Xue
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wenjia Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 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, China
| | - Yuying Sang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rafael J. L. Morcillo
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yaru Wang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 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, Chinese Academy of Sciences, Shanghai, China
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19
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Shen F, Yin W, Song S, Zhang Z, Ye P, Zhang Y, Zhou J, He F, Li P, Deng Y. Ralstonia solanacearum promotes pathogenicity by utilizing l-glutamic acid from host plants. Mol Plant Pathol 2020; 21:1099-1110. [PMID: 32599676 PMCID: PMC7368120 DOI: 10.1111/mpp.12963] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 05/20/2020] [Indexed: 05/22/2023]
Abstract
Ralstonia solanacearum is an important bacterial pathogen that can infect a broad range of plants worldwide. A previous study showed that R. solanacearum could respond to exogenous organic acids or amino acids to modulate cell motility. However, it was unclear whether R. solanacearum uses these compounds to control infection. In this study, we found that R. solanacearum GMI1000 uses host plant metabolites to enhance the biosynthesis of virulence factors. We demonstrated that l-glutamic acid from host plants is the key active component associated with increased extracellular polysaccharide production, cellulase activity, swimming motility, and biofilm formation in R. solanacearum GMI1000. In addition, l-glutamic acid also promoted colonization of R. solanacearum cells in the roots and stems of tomato plants and accelerated disease incidence. Furthermore, genetic screening and biochemical analysis suggested that RS01577, a hybrid sensor histidine kinase/response regulator, is involved in l-glutamic acid signalling in R. solanacearum. Mutations in RS01577 and exogenous addition of l-glutamic acid to the GMI1000 wild-type strain had overlapping effects on both the transcriptome and biological functions of R. solanacearum, including on motility, biofilm formation, and virulence. Thus, our results have established a new interaction mechanism between R. solanacearum and host plants that highlights the complexity of the virulence regulation mechanism and may provide new insight into disease control.
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Affiliation(s)
- Fangfang Shen
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Wenfang Yin
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Shihao Song
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Zhihan Zhang
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Peiyi Ye
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Jianuan Zhou
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Fei He
- College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Peng Li
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikouChina
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen)Sun Yat‐sen UniversityGuangzhouChina
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20
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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 Commun 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] [What about the content of this article? (0)] [Affiliation(s)] [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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21
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Wen T, Zhao M, Liu T, Huang Q, Yuan J, Shen Q. High abundance of Ralstonia solanacearum changed tomato rhizosphere microbiome and metabolome. BMC Plant Biol 2020; 20:166. [PMID: 32293273 PMCID: PMC7160980 DOI: 10.1186/s12870-020-02365-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 03/26/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND Rhizosphere microbiome is dynamic and influenced by environment factors surrounded including pathogen invasion. We studied the effects of Ralstonia solanacearum pathogen abundance on rhizosphere microbiome and metabolome by using high throughput sequencing and GC-MS technology. RESULTS There is significant difference between two rhizosphere bacterial communities of higher or lower pathogen abundance, and this difference of microbiomes was significant even ignoring the existence of pathogen. Higher pathogen abundance decreased the alpha diversity of rhizosphere bacterial community as well as connections in co-occurrence networks. Several bacterial groups such as Bacillus and Chitinophaga were negatively related to the pathogen abundance. The GC-MS analysis revealed significantly different metabolomes in two groups of rhizosphere soils, i.e., the rhizosphere soil of lower harbored more sugars such as fructose, sucrose and melibiose than that in high pathogen abundance. CONCLUSIONS The dissimilar metabolomes in two rhizosphere soils likely explained the difference of bacterial communities with Mantel test. Bacillus and Chitinophaga as well as sugar compounds negatively correlated with high abundance of pathogen indicated their potential biocontrol ability.
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Affiliation(s)
- Tao Wen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mengli Zhao
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ting Liu
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qiwei Huang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jun Yuan
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, China
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22
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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23
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Chen B, Long QS, Meng J, Zhou X, Wu ZB, Tuo XX, Ding Y, Zhang L, Wang PY, Li Z, Yang S. Target Discovery in Ralstonia solanacearum through an Activity-Based Protein Profiling Technique Based on Bioactive Oxadiazole Sulfones. J Agric Food Chem 2020; 68:2340-2346. [PMID: 32017553 DOI: 10.1021/acs.jafc.9b07192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ralstonia solanacearum is an extremely destructive and rebellious phytopathogen that can cause bacterial wilt diseases in more than 200 plant species. To explore and discover the potential targets in R. solanacearum for the purpose of developing new agrochemicals targeting this infection, here, we exploited a typical activity-based protein profiling technique for target discovery in R. solanacearum based on an activity-based probe 1 derived from bioactive oxadiazole sulfones. A total of 65 specific targets were identified with high confidence through a quantitative chemical proteomic approach. Three representative proteins (glycine cleavage system H protein, thiol peroxidase, and dihydrolipoamide S-succinyltransferase) were validated as the targets by using the immunoblotting analysis with their respective antibodies. Additionally, the in vitro interaction between the recombinant thiol peroxidase and probe 1 further confirmed that this protein was a target of oxadiazole sulfones. We anticipated that these discovered protein targets in R. solanacearum can stimulate the discovery and development of novel agrochemicals targeting bacterial infections caused by R. solanacearum.
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Affiliation(s)
- Biao Chen
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Qing-Su Long
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Jiao Meng
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Xiang Zhou
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Zhi-Bing Wu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Xin-Xin Tuo
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Yue Ding
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Ling Zhang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Pei-Yi Wang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
| | - Zhong Li
- College of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China
| | - Song Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education , Center for R&D of Fine Chemicals of Guizhou University , Guiyang 550025 , China
- College of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China
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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. Mol Plant Pathol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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25
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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. Mol Plant Pathol 2019; 20:1237-1251. [PMID: 31218811 PMCID: PMC6715614 DOI: 10.1111/mpp.12824] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Hayashi K, Kai K, Mori Y, Ishikawa S, Ujita Y, Ohnishi K, Kiba A, Hikichi Y. Contribution of a lectin, LecM, to the quorum sensing signalling pathway of Ralstonia solanacearum strain OE1-1. Mol Plant Pathol 2019; 20:334-345. [PMID: 30312504 PMCID: PMC6637872 DOI: 10.1111/mpp.12757] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The soil-borne bacterium Ralstonia solanacearum invades the roots and colonizes the intercellular spaces and then the xylem. The expression of lecM, encoding a lectin LecM, is induced by an OmpR family response regulator HrpG in R. solanacearum strain OE1-1. LecM contributes to the attachment of strain OE1-1 to the host cells of intercellular spaces. OE1-1 produces methyl 3-hydroxymyristate (3-OH MAME) through a methyltransferase (PhcB) and extracellularly secretes the chemical as a quorum sensing (QS) signal, which activates QS. The expression of lecM is also induced by the PhcA virulence regulator functioning through QS, and the resulting LecM is implicated in the QS-dependent production of major exopolysaccharide EPS I and the aggregation of OE1-1 cells. To investigate the function of LecM in QS, we analysed the transcriptome of R. solanacearum strains generated by RNA sequencing technology. In the lecM mutant, the expression of positively QS-regulated genes and negatively QS-regulated genes was down-regulated (by >90%) and up-regulated (by ~60%), respectively. However, phcB and phcA in the lecM mutant were expressed at levels similar to those in strain OE1-1. The lecM mutant produced significantly less ralfuranone and exhibited a significantly greater swimming motility, which were positively and negatively regulated by QS, respectively. In addition, the extracellular 3-OH MAME content of the lecM mutant was significantly lower than that of OE1-1. The application of 3-OH MAME more strongly increased EPS I production in the phcB-deleted mutant and strain OE1-1 than in the lecM mutant. Thus, the QS-dependent production of LecM contributes to the QS signalling pathway.
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Affiliation(s)
- Kazusa Hayashi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityNankokuKochi783‐8502Japan
| | - Kenji Kai
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiOsaka599‐8531Japan
| | - Yuka Mori
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityNankokuKochi783‐8502Japan
| | - Shiho Ishikawa
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityNankokuKochi783‐8502Japan
| | - Yumeto Ujita
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiOsaka599‐8531Japan
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi UniversityNankokuKochi783‐8502Japan
| | - Akinori Kiba
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityNankokuKochi783‐8502Japan
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityNankokuKochi783‐8502Japan
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27
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Alves MI, Macagnan KL, Piecha CR, Torres MM, Perez IA, Kesserlingh SM, Rodrigues RDS, de Oliveira PD, Moreira ADS. Optimization of Ralstonia solanacearum cell growth using a central composite rotational design for the P(3HB) production: Effect of agitation and aeration. PLoS One 2019; 14:e0211211. [PMID: 30695062 PMCID: PMC6350987 DOI: 10.1371/journal.pone.0211211] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 01/09/2019] [Indexed: 11/20/2022] Open
Abstract
The intracellular accumulation of polyhydroxyalkanoates (PHAs) normally occurs after cell growth, during the second fermentation stage and under nutrient-limited conditions in the presence of a carbon excess. However, some microorganisms are able to accumulate PHAs as poly(3-hydroxybutyrate) [P(3HB)] during the first fermentation stage, the cell growth phase, without nutrient limitation, once they have been reported to utilize type II metabolism during the polymer accumulation phase. This study evaluated the effect of aeration and agitation on cell growth and P(3HB) accumulation in Ralstonia solanacearum RS, performed in a bioreactor for 24h at 32°C. A 22 central composite rotational design (CCRD) was used, with agitation (150 to 250 rpm) and aeration (0.3 to 1 vvm) as independent variables and optical density (OD600nm), dry cell weight (DCW), and P(3HB) yield as dependent variables. A significant polymer accumulation, until 70% of P(3HB), was observed, proving that R. solanacearum RS exhibited metabolism type II, regardless of the aeration process. The best results were obtained for 1 vvm and 250 rpm (+1, +1), with values of OD600nm (18.04) and DCW (4.82 g.L-1).
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Affiliation(s)
- Mariane Igansi Alves
- Department of Food Science and Technology, Eliseu Maciel Faculty of Agronomy, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Karine Laste Macagnan
- Technological Development Center, Biotechnology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Camila Rios Piecha
- Technological Development Center, Biotechnology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Matheus Marques Torres
- Technological Development Center, Biotechnology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Izadora Almeida Perez
- Center for Chemical, Pharmaceutical and Food Science, University Federal of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | | | - Rosane da Silva Rodrigues
- Center for Chemical, Pharmaceutical and Food Science, University Federal of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Patrícia Diaz de Oliveira
- Department of Food Science and Technology, Eliseu Maciel Faculty of Agronomy, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
- Center for Chemical, Pharmaceutical and Food Science, University Federal of Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Angelita da Silveira Moreira
- Department of Food Science and Technology, Eliseu Maciel Faculty of Agronomy, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
- Technological Development Center, Biotechnology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil
- Center for Chemical, Pharmaceutical and Food Science, University Federal of Pelotas, Pelotas, Rio Grande do Sul, Brazil
- * E-mail:
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28
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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29
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Wang G, Kong J, Cui D, Zhao H, Zhao P, Feng S, Zhao Y, Wang W. Comparative Proteomic Analysis of Two Ralstonia solanacearum Isolates Differing in Aggressiveness. Int J Mol Sci 2018; 19:ijms19082444. [PMID: 30126218 PMCID: PMC6121549 DOI: 10.3390/ijms19082444] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/14/2018] [Accepted: 08/17/2018] [Indexed: 01/02/2023] Open
Abstract
Ralstonia solanacearum is a soil-borne, plant xylem-infecting pathogen that causes the devastating bacterial wilt (BW) disease in a number of plant species. In the present study, two R. solanacearum strains with different degrees of aggressiveness―namely RsH (pathogenic to Hawaii 7996, a tomato cultivar resistant against most strains) and RsM (non-pathogenic to Hawaii 7996) were identified. Phylogenetic analysis revealed that both RsM and RsH belonged to phylotype I. To further elucidate the underlying mechanism of the different pathotypes between the two strains, we performed a comparative proteomics study on RsM and RsH in rich and minimal media to identify the change in the level of protein abundance. In total, 24 differential proteins were identified, with four clusters in terms of protein abundance. Further bioinformatics exploration allowed us to classify these proteins into five functional groups. Notably, the pathogenesis of RsM and RsH was particularly characterized by a pronounced difference in the abundance of virulence- and metabolism-related proteins, such as UDP-N-acetylglucosamine 2-epimerase (epsC) and isocitrate lyase (ICL), which were more abundant in the high pathogenicity strain RsH. Thus, we propose that the differences in pathogenicity between RsM and RsH can possibly be partially explained by differences in extracellular polysaccharide (EPS) and glyoxylate metabolism-related proteins.
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Affiliation(s)
- Guoping Wang
- Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China, Ministry of Agriculture, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
| | - Jie Kong
- Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Dandan Cui
- Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China, Ministry of Agriculture, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
| | - Hongbo Zhao
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
| | - Puyan Zhao
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
| | - Shujie Feng
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
| | - Yahua Zhao
- Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Wenyi Wang
- Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China, Ministry of Agriculture, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
- Department of Plant Science, Weizmann Institute of Science, Rehovot 76100, Israel.
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Wei Y, Caceres‐Moreno C, Jimenez‐Gongora T, Wang K, Sang Y, Lozano‐Duran R, Macho AP. The Ralstonia solanacearum csp22 peptide, but not flagellin-derived peptides, is perceived by plants from the Solanaceae family. Plant Biotechnol J 2018; 16:1349-1362. [PMID: 29265643 PMCID: PMC5999195 DOI: 10.1111/pbi.12874] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/10/2017] [Accepted: 12/12/2017] [Indexed: 05/20/2023]
Abstract
Ralstonia solanacearum, the causal agent of bacterial wilt disease, is considered one of the most destructive bacterial pathogens due to its lethality, unusually wide host range, persistence and broad geographical distribution. In spite of the extensive research on plant immunity over the last years, the perception of molecular patterns from R. solanacearum that activate immunity in plants is still poorly understood, which hinders the development of strategies to generate resistance against bacterial wilt disease. The perception of a conserved peptide of bacterial flagellin, flg22, is regarded as paradigm of plant perception of invading bacteria; however, no elicitor activity has been detected for R. solanacearum flg22. Recent reports have shown that other epitopes from flagellin are able to elicit immune responses in specific species from the Solanaceae family, yet our results show that these plants do not perceive any epitope from R. solanacearum flagellin. Searching for elicitor peptides from R. solanacearum, we found several protein sequences similar to the consensus of the elicitor peptide csp22, reported to elicit immunity in specific Solanaceae plants. A R. solanacearum csp22 peptide (csp22Rsol ) was indeed able to trigger immune responses in Nicotiana benthamiana and tomato, but not in Arabidopsis thaliana. Additionally, csp22Rsol treatment conferred increased resistance to R. solanacearum in tomato. Transgenic A. thaliana plants expressing the tomato csp22 receptor (SlCORE) gained the ability to respond to csp22Rsol and became more resistant to R. solanacearum infection. Our results shed light on the mechanisms for perception of R. solanacearum by plants, paving the way for improving current approaches to generate resistance against R. solanacearum.
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Affiliation(s)
- Yali Wei
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Carlos Caceres‐Moreno
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Tamara Jimenez‐Gongora
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Keke Wang
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Yuying Sang
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Rosa Lozano‐Duran
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Alberto P. Macho
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
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31
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Tancos MA, Lowe‐Power TM, Peritore‐Galve FC, Tran TM, Allen C, Smart CD. Plant-like bacterial expansins play contrasting roles in two tomato vascular pathogens. Mol Plant Pathol 2018; 19:1210-1221. [PMID: 28868644 PMCID: PMC5835177 DOI: 10.1111/mpp.12611] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/04/2017] [Accepted: 08/31/2017] [Indexed: 05/27/2023]
Abstract
Expansin proteins, which loosen plant cell walls, play critical roles in normal plant growth and development. The horizontal acquisition of functional plant-like expansin genes in numerous xylem-colonizing phytopathogenic bacteria suggests that bacterial expansins may also contribute to virulence. To investigate the role of bacterial expansins in plant diseases, we mutated the non-chimeric expansin genes (CmEXLX2 and RsEXLX) of two xylem-inhabiting bacterial pathogens, the Actinobacterium Clavibacter michiganensis ssp. michiganensis (Cmm) and the β-proteobacterium Ralstonia solanacearum (Rs), respectively. The Cmm ΔCmEXLX2 mutant caused increased symptom development on tomato, which was characterized by more rapid wilting, greater vascular necrosis and abundant atypical lesions on distant petioles. This increased disease severity correlated with larger in planta populations of the ΔCmEXLX2 mutant, even though the strains grew as well as the wild-type in vitro. Similarly, when inoculated onto tomato fruit, ΔCmEXLX2 caused significantly larger lesions with larger necrotic centres. In contrast, the Rs ΔRsEXLX mutant showed reduced virulence on tomato following root inoculation, but not following direct petiole inoculation, suggesting that the RsEXLX expansin contributes to early virulence at the root infection stage. Consistent with this finding, ΔRsEXLX attached to tomato seedling roots better than the wild-type Rs, which may prevent mutants from invading the plant's vasculature. These contrasting results demonstrate the diverse roles of non-chimeric bacterial expansins and highlight their importance in plant-bacterial interactions.
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Affiliation(s)
- Matthew A. Tancos
- Plant Pathology and Plant‐Microbe Biology Section, School of Integrative Plant SciencesCornell UniversityGenevaNY 14456USA
- Present address:
Foreign Disease‐Weed Science Research Unit, USDA‐ARSFort DetrickMD 21702USA
| | | | - F. Christopher Peritore‐Galve
- Plant Pathology and Plant‐Microbe Biology Section, School of Integrative Plant SciencesCornell UniversityGenevaNY 14456USA
| | - Tuan M. Tran
- Department of Plant PathologyUniversity of Wisconsin‐MadisonMadisonWI 53706USA
- Present address:
School of Biological SciencesNanyang Technological University639798Singapore
| | - Caitilyn Allen
- Department of Plant PathologyUniversity of Wisconsin‐MadisonMadisonWI 53706USA
| | - Christine D. Smart
- Plant Pathology and Plant‐Microbe Biology Section, School of Integrative Plant SciencesCornell UniversityGenevaNY 14456USA
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32
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Mori Y, Hosoi Y, Ishikawa S, Hayashi K, Asai Y, Ohnishi H, Shimatani M, Inoue K, Ikeda K, Nakayashiki H, Nishimura Y, Ohnishi K, Kiba A, Kai K, Hikichi Y. Ralfuranones contribute to mushroom-type biofilm formation by Ralstonia solanacearum strain OE1-1. Mol Plant Pathol 2018; 19:975-985. [PMID: 28722830 PMCID: PMC6638155 DOI: 10.1111/mpp.12583] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 07/04/2017] [Accepted: 07/15/2017] [Indexed: 06/01/2023]
Abstract
After invasion into intercellular spaces of tomato plants, the soil-borne, plant-pathogenic Ralstonia solanacearum strain OE1-1 forms mushroom-shaped biofilms (mushroom-type biofilms, mBFs) on tomato cells, leading to its virulence. The strain OE1-1 produces aryl-furanone secondary metabolites, ralfuranones (A, B, J, K and L), dependent on the quorum sensing (QS) system, with methyl 3-hydroxymyristate (3-OH MAME) synthesized by PhcB as a QS signal. Ralfuranones are associated with the feedback loop of the QS system. A ralfuranone productivity-deficient mutant (ΔralA) exhibited significantly reduced growth in intercellular spaces compared with strain OE1-1, losing its virulence. To analyse the function of ralfuranones in mBF formation by OE1-1 cells, we observed cell aggregates of R. solanacearum strains statically incubated in tomato apoplast fluids on filters under a scanning electron microscope. The ΔralA strain formed significantly fewer microcolonies and mBFs than strain OE1-1. Supplementation of ralfuranones A, B, J and K, but not L, significantly enhanced the development of mBF formation by ΔralA. Furthermore, a phcB- and ralA-deleted mutant (ΔphcB/ralA) exhibited less formation of mBFs than OE1-1, although a QS-deficient, phcB-deleted mutant formed mBFs similar to OE1-1. Supplementation with 3-OH MAME significantly reduced the formation of mBFs by ΔphcB/ralA. The application of each ralfuranone significantly increased the formation of mBFs by ΔphcB/ralA supplied with 3-OH MAME. Together, our findings indicate that ralfuranones are implicated not only in the development of mBFs by strain OE1-1, but also in the suppression of QS-mediated negative regulation of mBF formation.
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Affiliation(s)
- Yuka Mori
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Yuki Hosoi
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Shiho Ishikawa
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Kazusa Hayashi
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Yu Asai
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Hideyuki Ohnishi
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiOsaka599‐8531Japan
| | - Mika Shimatani
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiOsaka599‐8531Japan
| | - Kanako Inoue
- Research Center for Ultra‐High Voltage Electron MicroscopyOsaka University, MihogaokaIbarakiOsaka567‐0047Japan
| | - Kenichi Ikeda
- Graduate School of Agricultural ScienceKobe UniversityNada‐ku, KobeHyogo657‐8501Japan
| | - Hitoshi Nakayashiki
- Graduate School of Agricultural ScienceKobe UniversityNada‐ku, KobeHyogo657‐8501Japan
| | - Yasuyo Nishimura
- Laboratory of Horticultural ScienceKochi University, NankokuKochi783‐8502Japan
| | - Kouhei Ohnishi
- Research Institute of Molecular GeneticsKochi University, NankokuKochi783‐8502Japan
| | - Akinori Kiba
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Kenji Kai
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiOsaka599‐8531Japan
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
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Mori Y, Ishikawa S, Ohnishi H, Shimatani M, Morikawa Y, Hayashi K, Ohnishi K, Kiba A, Kai K, Hikichi Y. Involvement of ralfuranones in the quorum sensing signalling pathway and virulence of Ralstonia solanacearum strain OE1-1. Mol Plant Pathol 2018; 19:454-463. [PMID: 28116815 PMCID: PMC6638173 DOI: 10.1111/mpp.12537] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 05/02/2023]
Abstract
The soil-borne, plant-pathogenic Ralstonia solanacearum strain OE1-1 produces and secretes methyl 3-hydroxymyristate (3-OH MAME) as a quorum sensing (QS) signal, which contributes to its virulence. A global virulence regulator, PhcA, functioning through the QS system, positively regulates the expression of ralA, which encodes furanone synthase, to produce aryl-furanone secondary metabolites, ralfuranones. A ralfuranone-deficient mutant (ΔralA) is weakly virulent when directly inoculated into tomato xylem vessels. To investigate the functions of ralfuranones, we analysed R. solanacearum transcriptome data generated by RNA sequencing technology. ΔralA expressed phcB, which is associated with 3-OH MAME production, and phcA at levels similar to those in strain OE1-1. In addition, ΔralA exhibited down-regulated expression of more than 90% of the QS positively regulated genes, and up-regulated expression of more than 75% of the QS negatively regulated genes. These results suggest that ralfuranones affect the QS feedback loop. Ralfuranone supplementation restored the ability of ΔralA cells to aggregate. In addition, ralfuranones A and B restored the swimming motility of ΔralA to wild-type levels. However, the application of exogenous ralfuranones did not affect the production of the major exopolysaccharide, EPS I, in ΔralA. Quantitative real-time polymerase chain reaction assays revealed that the deletion of ralA results in the down-regulated expression of vsrAD and vsrBC, which encode a sensor kinase and a response regulator, respectively, in the two-component regulatory systems that influence EPS I production. The application of ralfuranone B restored the expression of these two genes. Overall, our findings indicate that integrated signalling via ralfuranones influences the QS and virulence of R. solanacearum.
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Affiliation(s)
- Yuka Mori
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Shiho Ishikawa
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Hideyuki Ohnishi
- Graduate School of Life and Environmental SciencesOsaka Prefecture University, SakaiOsaka599‐8531Japan
| | - Mika Shimatani
- Graduate School of Life and Environmental SciencesOsaka Prefecture University, SakaiOsaka599‐8531Japan
| | - Yukino Morikawa
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Kazusa Hayashi
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Kouhei Ohnishi
- Research Institute of Molecular GeneticsKochi University, NankokuKochi783‐8502Japan
| | - Akinori Kiba
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
| | - Kenji Kai
- Graduate School of Life and Environmental SciencesOsaka Prefecture University, SakaiOsaka599‐8531Japan
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi University, NankokuKochi783‐8502Japan
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Lu H, Lema A S, Planas-Marquès M, Alonso-Díaz A, Valls M, Coll NS. Type III Secretion-Dependent and -Independent Phenotypes Caused by Ralstonia solanacearum in Arabidopsis Roots. Mol Plant Microbe Interact 2018; 31:175-184. [PMID: 28840786 DOI: 10.1094/mpmi-05-17-0109-fi] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The causal agent of bacterial wilt, Ralstonia solanacearum, is a soilborne pathogen that invades plants through their roots, traversing many tissue layers until it reaches the xylem, where it multiplies and causes plant collapse. The effects of R. solanacearum infection are devastating, and no effective approach to fight the disease is so far available. The early steps of infection, essential for colonization, as well as the early plant defense responses remain mostly unknown. Here, we have set up a simple, in vitro Arabidopsis thaliana-R. solanacearum pathosystem that has allowed us to identify three clear root phenotypes specifically associated to the early stages of infection: root-growth inhibition, root-hair formation, and root-tip cell death. Using this method, we have been able to differentiate, on Arabidopsis plants, the phenotypes caused by mutants in the key bacterial virulence regulators hrpB and hrpG, which remained indistinguishable using the classical soil-drench inoculation pathogenicity assays. In addition, we have revealed the previously unknown involvement of auxins in the root rearrangements caused by R. solanacearum infection. Our system provides an easy-to-use, high-throughput tool to study R. solanacearum aggressiveness. Furthermore, the observed phenotypes may allow the identification of bacterial virulence determinants and could even be used to screen for novel forms of early plant resistance to bacterial wilt.
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Affiliation(s)
- Haibin Lu
- 1 Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain; and
| | - Saul Lema A
- 1 Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain; and
| | - Marc Planas-Marquès
- 1 Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain; and
| | - Alejandro Alonso-Díaz
- 1 Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain; and
| | - Marc Valls
- 1 Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain; and
- 2 Genetics Department, Universitat de Barcelona, Catalonia, Spain
| | - Núria S Coll
- 1 Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain; and
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Sang Y, Wang Y, Ni H, Cazalé A, She Y, Peeters N, Macho AP. The Ralstonia solanacearum type III effector RipAY targets plant redox regulators to suppress immune responses. Mol Plant Pathol 2018; 19:129-142. [PMID: 27768829 PMCID: PMC6638004 DOI: 10.1111/mpp.12504] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 09/28/2016] [Accepted: 10/17/2016] [Indexed: 05/07/2023]
Abstract
The subversion of plant cellular functions is essential for bacterial pathogens to proliferate in host plants and cause disease. Most bacterial plant pathogens employ a type III secretion system to inject type III effector (T3E) proteins inside plant cells, where they contribute to the pathogen-induced alteration of plant physiology. In this work, we found that the Ralstonia solanacearum T3E RipAY suppresses plant immune responses triggered by bacterial elicitors and by the phytohormone salicylic acid. Further biochemical analysis indicated that RipAY associates in planta with thioredoxins from Nicotiana benthamiana and Arabidopsis. Interestingly, RipAY displays γ-glutamyl cyclotransferase (GGCT) activity to degrade glutathione in plant cells, which is required for the reported suppression of immune responses. Given the importance of thioredoxins and glutathione as major redox regulators in eukaryotic cells, RipAY activity may constitute a novel and powerful virulence strategy employed by R. solanacearum to suppress immune responses and potentially alter general redox signalling in host cells.
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Affiliation(s)
- Yuying Sang
- Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 201602China
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 200031China
| | - Yaru Wang
- Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 201602China
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 200031China
| | - Hong Ni
- Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 201602China
| | | | - Yi‐Min She
- Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 201602China
| | - Nemo Peeters
- LIPM, Université de Toulouse, INRA, CNRSCastanet‐Tolosan 31326France
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 201602China
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of SciencesShanghai 200031China
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Zhang ZM, Ma KW, Gao L, Hu Z, Schwizer S, Ma W, Song J. Mechanism of host substrate acetylation by a YopJ family effector. Nat Plants 2017; 3:17115. [PMID: 28737762 PMCID: PMC5546152 DOI: 10.1038/nplants.2017.115] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/26/2017] [Indexed: 05/22/2023]
Abstract
The Yersinia outer protein J (YopJ) family of bacterial effectors depends on a novel acetyltransferase domain to acetylate signalling proteins from plant and animal hosts. However, the underlying mechanism is unclear. Here, we report the crystal structures of PopP2, a YopJ effector produced by the plant pathogen Ralstonia solanacearum, in complex with inositol hexaphosphate (InsP6), acetyl-coenzyme A (AcCoA) and/or substrate Resistance to Ralstonia solanacearum 1 (RRS1-R)WRKY. PopP2 recognizes the WRKYGQK motif of RRS1-RWRKY to position a targeted lysine in the active site for acetylation. Importantly, the PopP2-RRS1-RWRKY association is allosterically regulated by InsP6 binding, suggesting a previously unidentified role of the eukaryote-specific cofactor in substrate interaction. Furthermore, we provide evidence for the reaction intermediate of PopP2-mediated acetylation, an acetyl-cysteine covalent adduct, lending direct support to the 'ping-pong'-like catalytic mechanism proposed for YopJ effectors. Our study provides critical mechanistic insights into the virulence activity of YopJ class of acetyltransferases.
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Affiliation(s)
- Zhi-Min Zhang
- Department of Biochemistry, University of California, Riverside, California 92521, USA
| | - Ka-Wai Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
| | - Linfeng Gao
- Environmental Toxicology Program, University of California, Riverside, California 92521, USA
| | - Zhenquan Hu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Anhui 230031, China
| | - Simon Schwizer
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
| | - Wenbo Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
- Center for Plant Cell Biology, University of California, Riverside, California 92521, USA
- Institute of Integrative Genome Biology, University of California, Riverside, California 92521, USA
| | - Jikui Song
- Department of Biochemistry, University of California, Riverside, California 92521, USA
- Environmental Toxicology Program, University of California, Riverside, California 92521, USA
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Chen J, Li S, Luo J, Zhang Y, Ding W. Graphene Oxide Induces Toxicity and Alters Energy Metabolism and Gene Expression in Ralstonia solanacearum. J Nanosci Nanotechnol 2017; 17:186-195. [PMID: 29617100 DOI: 10.1166/jnn.2017.12575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Graphene oxide (GO) is a promising material for development as an antibacterial, phytoprotective agent due to its contact-based antibacterial activity induced by its physical and chemical properties. However, the mechanism underlying the antibacterial effect of GO has yet to be elucidated. In the current study, we investigated the effects of GO on the phytopathogen R. solanacearum at the molecular level with a specific focus on energy metabolism. Under controlled conditions, the bacteriostatic and bactericidal actions of GO were investigated with respect to concentration, treatment time and rotation speed. Transmission electron microscopy (TEM) and destabilization assays revealed that GO caused injury to bacterial cell membrane structures. Furthermore, adenosine triphosphate (ATP) levels decreased after exposure to sheets of GO, while malondialdehyde levels significantly increased, indicating the occurrence of lipid oxidation. A series of genes related to bacterial virulence, motility and oxidative stress were selected to evaluate the molecular mechanism underlying GO’s effects on R. solanacearum. Using quantitative reverse transcription polymerase chain reaction (RT-qPCR), we showed that in the presence of GO, the expression levels of genes involved in virulence and motility were down regulated, with the exception of popA. The phcA, hrpB and flgG genes were significantly downregulated by 2.61-, 3.45- and 4.22-fold, respectively. Conversely, the expression levels of sodB, oxyR and dps, three important oxidative stress genes, were upregulated by 1.82-, 2.17-, and 3.79-fold, respectively. These findings confirmed that cell membrane damage and oxidative stress were responsible for the antibacterial actions of GO, in addition to disturbances to energy metabolism processes.
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Perrier A, Peyraud R, Rengel D, Barlet X, Lucasson E, Gouzy J, Peeters N, Genin S, Guidot A. Enhanced in planta Fitness through Adaptive Mutations in EfpR, a Dual Regulator of Virulence and Metabolic Functions in the Plant Pathogen Ralstonia solanacearum. PLoS Pathog 2016; 12:e1006044. [PMID: 27911943 PMCID: PMC5135139 DOI: 10.1371/journal.ppat.1006044] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/05/2016] [Indexed: 11/18/2022] Open
Abstract
Experimental evolution of the plant pathogen Ralstonia solanacearum, where bacteria were maintained on plant lineages for more than 300 generations, revealed that several independent single mutations in the efpR gene from populations propagated on beans were associated with fitness gain on bean. In the present work, novel allelic efpR variants were isolated from populations propagated on other plant species, thus suggesting that mutations in efpR were not solely associated to a fitness gain on bean, but also on additional hosts. A transcriptomic profiling and phenotypic characterization of the efpR deleted mutant showed that EfpR acts as a global catabolic repressor, directly or indirectly down-regulating the expression of multiple metabolic pathways. EfpR also controls virulence traits such as exopolysaccharide production, swimming and twitching motilities and deletion of efpR leads to reduced virulence on tomato plants after soil drenching inoculation. We studied the impact of the single mutations that occurred in efpR during experimental evolution and found that these allelic mutants displayed phenotypic characteristics similar to the deletion mutant, although not behaving as complete loss-of-function mutants. These adaptive mutations therefore strongly affected the function of efpR, leading to an expanded metabolic versatility that should benefit to the evolved clones. Altogether, these results indicated that EfpR is a novel central player of the R. solanacearum virulence regulatory network. Independent mutations therefore appeared during experimental evolution in the evolved clones, on a crucial node of this network, to favor adaptation to host vascular tissues through regulatory and metabolic rewiring. Among plant pathogens of major economic and food crops, Ralstonia solanacearum, the causal agent of bacterial wilt, is recognized as one of the most destructive plant bacterial diseases. In addition, the emergence of new pathotypes, more aggressive and adapted to new hosts, has been reported. During an evolution experiment of R. solanacearum, where bacteria were maintained on plant lineages for more than 300 generations, we demonstrated that several single mutations in the regulatory gene efpR were associated with fitness gain on plants. However, the function of the EfpR regulator was totally unknown. In this work, we provided evidence that EfpR controls several metabolic pathways and important virulence traits of R. solanacearum. We then demonstrated that the single mutations selected in the efpR gene during the evolution experiment strongly alter the efpR expression, and thus enlarge the metabolic capacities of the bacterial cell. Altogether, our study reveals that EfpR is a novel key component of the complex regulatory network of the R. solanacearum cell, tightly linking the bacterial metabolism to virulence in response to multiple environmental signals.
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Affiliation(s)
- Anthony Perrier
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Rémi Peyraud
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - David Rengel
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Xavier Barlet
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | | | - Jérôme Gouzy
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Nemo Peeters
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Stéphane Genin
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
- * E-mail: (SG); (AG)
| | - Alice Guidot
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
- * E-mail: (SG); (AG)
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Bai W, Kong F, Lin Y, Zhang C. Extract of Syringa oblata: A new biocontrol agent against tobacco bacterial wilt caused by Ralstonia solanacearum. Pestic Biochem Physiol 2016; 134:79-83. [PMID: 27914543 DOI: 10.1016/j.pestbp.2016.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/06/2016] [Accepted: 04/08/2016] [Indexed: 06/06/2023]
Abstract
Ralstonia solanacearum causes serious wilt disease in tobacco. To effectively control this disease, the antibacterial activity of 95% ethanol extracts from the flower buds of Syringa oblata was examined. Based on GC-MS analysis and an inhibition experiment against R. solanacearum, the main antibacterial component is eugenol. We further determined the effect of eugenol on the physiology, biochemistry, and cellular morphology of R. solanacearum. The results showed that eugenol can destroy wilt bacteria, leading to the disappearance of flagella, the leakage of contents, and the appearance of a cavity. SDS-PAGE showed that eugenol decreased protein content in R. solanacearum, reduced medium carbohydrate utilization, and inhibited CAT and SDH activity. The above results showed that eugenol had a significant inhibitory effect on R. solanacearum and this component has the potential to prevent tobacco bacterial wilt.
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Affiliation(s)
- Wanming Bai
- Pest Integrated Management Key Laboratory of China Tobacco, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China; Tobacco Research Institute of Nanping, Nangping, China
| | - Fanyu Kong
- Pest Integrated Management Key Laboratory of China Tobacco, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Yong Lin
- Tobacco Research Institute of Nanping, Nangping, China
| | - Chengsheng Zhang
- Pest Integrated Management Key Laboratory of China Tobacco, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
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Lowe-Power TM, Jacobs JM, Ailloud F, Fochs B, Prior P, Allen C. Degradation of the Plant Defense Signal Salicylic Acid Protects Ralstonia solanacearum from Toxicity and Enhances Virulence on Tobacco. mBio 2016; 7:e00656-16. [PMID: 27329752 PMCID: PMC4916378 DOI: 10.1128/mbio.00656-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/09/2016] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Plants use the signaling molecule salicylic acid (SA) to trigger defenses against diverse pathogens, including the bacterial wilt pathogen Ralstonia solanacearum SA can also inhibit microbial growth. Most sequenced strains of the heterogeneous R. solanacearum species complex can degrade SA via gentisic acid to pyruvate and fumarate. R. solanacearum strain GMI1000 expresses this SA degradation pathway during tomato pathogenesis. Transcriptional analysis revealed that subinhibitory SA levels induced expression of the SA degradation pathway, toxin efflux pumps, and some general stress responses. Interestingly, SA treatment repressed expression of virulence factors, including the type III secretion system, suggesting that this pathogen may suppress virulence functions when stressed. A GMI1000 mutant lacking SA degradation activity was much more susceptible to SA toxicity but retained the wild-type colonization ability and virulence on tomato. This may be because SA is less important than gentisic acid in tomato defense signaling. However, another host, tobacco, responds strongly to SA. To test the hypothesis that SA degradation contributes to virulence on tobacco, we measured the effect of adding this pathway to the tobacco-pathogenic R. solanacearum strain K60, which lacks SA degradation genes. Ectopic addition of the GMI1000 SA degradation locus, including adjacent genes encoding two porins and a LysR-type transcriptional regulator, significantly increased the virulence of strain K60 on tobacco. Together, these results suggest that R. solanacearum degrades plant SA to protect itself from inhibitory levels of this compound and also to enhance its virulence on plant hosts like tobacco that use SA as a defense signal molecule. IMPORTANCE Plant pathogens such as the bacterial wilt agent Ralstonia solanacearum threaten food and economic security by causing significant losses for small- and large-scale growers of tomato, tobacco, banana, potato, and ornamentals. Like most plants, these crop hosts use salicylic acid (SA) both indirectly as a signal to activate defenses and directly as an antimicrobial chemical. We found that SA inhibits growth of R. solanacearum and induces a general stress response that includes repression of multiple bacterial wilt virulence factors. The ability to degrade SA reduces the pathogen's sensitivity to SA toxicity and increases its virulence on tobacco.
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Affiliation(s)
- Tiffany M Lowe-Power
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jonathan M Jacobs
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, USA Institut de Recherche pour le Développement, UMR Interactions Plantes Microorganismes Environnement, Montpellier, France
| | - Florent Ailloud
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, CIRAD-INRA, Saint-Pierre, La Réunion, France Laboratoire de la Santé des Végétaux, Agence Nationale Sécurité Sanitaire Alimentaire Nationale, Saint-Pierre, La Réunion, France
| | - Brianna Fochs
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Philippe Prior
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, CIRAD-INRA, Saint-Pierre, La Réunion, France
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Popa C, Li L, Gil S, Tatjer L, Hashii K, Tabuchi M, Coll NS, Ariño J, Valls M. The effector AWR5 from the plant pathogen Ralstonia solanacearum is an inhibitor of the TOR signalling pathway. Sci Rep 2016; 6:27058. [PMID: 27257085 PMCID: PMC4891724 DOI: 10.1038/srep27058] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/12/2016] [Indexed: 01/31/2023] Open
Abstract
Bacterial pathogens possess complex type III effector (T3E) repertoires that are translocated inside the host cells to cause disease. However, only a minor proportion of these effectors have been assigned a function. Here, we show that the T3E AWR5 from the phytopathogen Ralstonia solanacearum is an inhibitor of TOR, a central regulator in eukaryotes that controls the switch between cell growth and stress responses in response to nutrient availability. Heterologous expression of AWR5 in yeast caused growth inhibition and autophagy induction coupled to massive transcriptomic changes, unmistakably reminiscent of TOR inhibition by rapamycin or nitrogen starvation. Detailed genetic analysis of these phenotypes in yeast, including suppression of AWR5-induced toxicity by mutation of CDC55 and TPD3, encoding regulatory subunits of the PP2A phosphatase, indicated that AWR5 might exert its function by directly or indirectly inhibiting the TOR pathway upstream PP2A. We present evidence in planta that this T3E caused a decrease in TOR-regulated plant nitrate reductase activity and also that normal levels of TOR and the Cdc55 homologues in plants are required for R. solanacearum virulence. Our results suggest that the TOR pathway is a bona fide T3E target and further prove that yeast is a useful platform for T3E function characterisation.
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Affiliation(s)
- Crina Popa
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Liang Li
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Sergio Gil
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Laura Tatjer
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalonia, Spain
| | - Keisuke Hashii
- Laboratory of Applied Molecular and Cell Biology, Kagawa University, Kagawa, Japan
| | - Mitsuaki Tabuchi
- Laboratory of Applied Molecular and Cell Biology, Kagawa University, Kagawa, Japan
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalonia, Spain
| | - Marc Valls
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
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Tran TM, MacIntyre A, Hawes M, Allen C. Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum. PLoS Pathog 2016; 12:e1005686. [PMID: 27336156 PMCID: PMC4919084 DOI: 10.1371/journal.ppat.1005686] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/18/2016] [Indexed: 12/21/2022] Open
Abstract
Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner. These traps rapidly immobilized the pathogen and killed some cells, but most of the entangled bacteria eventually escaped. The R. solanacearum genome encodes two putative extracellular DNases (exDNases) that are expressed during pathogenesis, suggesting that these exDNases contribute to bacterial virulence by enabling the bacterium to degrade and escape root border cell traps. We tested this hypothesis with R. solanacearum deletion mutants lacking one or both of these nucleases, named NucA and NucB. Functional studies with purified proteins revealed that NucA and NucB are non-specific endonucleases and that NucA is membrane-associated and cation-dependent. Single ΔnucA and ΔnucB mutants and the ΔnucA/B double mutant all had reduced virulence on wilt-susceptible tomato plants in a naturalistic soil-soak inoculation assay. The ΔnucA/B mutant was out-competed by the wild-type strain in planta and was less able to stunt root growth or colonize plant stems. Further, the double nuclease mutant could not escape from root border cells in vitro and was defective in attachment to pea roots. Taken together, these results demonstrate that extracellular DNases are novel virulence factors that help R. solanacearum successfully overcome plant defenses to infect plant roots and cause bacterial wilt disease.
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Affiliation(s)
- Tuan Minh Tran
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - April MacIntyre
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Martha Hawes
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Arizona, United States of America
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Tran TM, MacIntyre A, Hawes M, Allen C. Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum. PLoS Pathog 2016; 12:e1005686. [PMID: 27336156 DOI: 10.1371/journal.ppat.10056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/18/2016] [Indexed: 05/22/2023] Open
Abstract
Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner. These traps rapidly immobilized the pathogen and killed some cells, but most of the entangled bacteria eventually escaped. The R. solanacearum genome encodes two putative extracellular DNases (exDNases) that are expressed during pathogenesis, suggesting that these exDNases contribute to bacterial virulence by enabling the bacterium to degrade and escape root border cell traps. We tested this hypothesis with R. solanacearum deletion mutants lacking one or both of these nucleases, named NucA and NucB. Functional studies with purified proteins revealed that NucA and NucB are non-specific endonucleases and that NucA is membrane-associated and cation-dependent. Single ΔnucA and ΔnucB mutants and the ΔnucA/B double mutant all had reduced virulence on wilt-susceptible tomato plants in a naturalistic soil-soak inoculation assay. The ΔnucA/B mutant was out-competed by the wild-type strain in planta and was less able to stunt root growth or colonize plant stems. Further, the double nuclease mutant could not escape from root border cells in vitro and was defective in attachment to pea roots. Taken together, these results demonstrate that extracellular DNases are novel virulence factors that help R. solanacearum successfully overcome plant defenses to infect plant roots and cause bacterial wilt disease.
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Affiliation(s)
- Tuan Minh Tran
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - April MacIntyre
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Martha Hawes
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Arizona, United States of America
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Wang K, Remigi P, Anisimova M, Lonjon F, Kars I, Kajava A, Li CH, Cheng CP, Vailleau F, Genin S, Peeters N. Functional assignment to positively selected sites in the core type III effector RipG7 from Ralstonia solanacearum. Mol Plant Pathol 2016; 17:553-64. [PMID: 26300048 PMCID: PMC6638336 DOI: 10.1111/mpp.12302] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The soil-borne pathogen Ralstonia solanacearum causes bacterial wilt in a broad range of plants. The main virulence determinants of R. solanacearum are the type III secretion system (T3SS) and its associated type III effectors (T3Es), translocated into the host cells. Of the conserved T3Es among R. solanacearum strains, the Fbox protein RipG7 is required for R. solanacearum pathogenesis on Medicago truncatula. In this work, we describe the natural ripG7 variability existing in the R. solanacearum species complex. We show that eight representative ripG7 orthologues have different contributions to pathogenicity on M. truncatula: only ripG7 from Asian or African strains can complement the absence of ripG7 in GMI1000 (Asian reference strain). Nonetheless, RipG7 proteins from American and Indonesian strains can still interact with M. truncatula SKP1-like/MSKa protein, essential for the function of RipG7 in virulence. This indicates that the absence of complementation is most likely a result of the variability in the leucine-rich repeat (LRR) domain of RipG7. We identified 11 sites under positive selection in the LRR domains of RipG7. By studying the functional impact of these 11 sites, we show the contribution of five positively selected sites for the function of RipG7CMR15 in M. truncatula colonization. This work reveals the genetic and functional variation of the essential core T3E RipG7 from R. solanacearum. This analysis is the first of its kind on an essential disease-controlling T3E, and sheds light on the co-evolutionary arms race between the bacterium and its hosts.
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Affiliation(s)
- Keke Wang
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
| | - Philippe Remigi
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
| | - Maria Anisimova
- Institute of Applied Simulations, School of Life Sciences and Facility Management, Zürich University of Applied Sciences, Gruenalstrasse 14, 8820, Wädesnwil, Switzerland
| | - Fabien Lonjon
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
| | - Ilona Kars
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
| | - Andrey Kajava
- Centre de Recherche de Biochimie Macromoléculaire, CNRS, UMR5237, 1919 Route de Mende, 34000, Montpellier, France
| | - Chien-Hui Li
- Institute of Plant Biology, National Taiwan University, Taipei, 11529, Taiwan, R.O.C
| | - Chiu-Ping Cheng
- Institute of Plant Biology, National Taiwan University, Taipei, 11529, Taiwan, R.O.C
| | - Fabienne Vailleau
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- Université de Toulouse, INP, ENSAT, 18 Chemin de Borde Rouge, Castanet-Tolosan, 31326, France
| | - Stéphane Genin
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
| | - Nemo Peeters
- INRA, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR441, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR2594, CS52627 Chemin de Borde Rouge, 31326, Castanet-Tolosan, France
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Mukaihara T, Hatanaka T, Nakano M, Oda K. Ralstonia solanacearum Type III Effector RipAY Is a Glutathione-Degrading Enzyme That Is Activated by Plant Cytosolic Thioredoxins and Suppresses Plant Immunity. mBio 2016; 7:e00359-16. [PMID: 27073091 PMCID: PMC4959522 DOI: 10.1128/mbio.00359-16] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The plant pathogen Ralstonia solanacearum uses a large repertoire of type III effector proteins to succeed in infection. To clarify the function of effector proteins in host eukaryote cells, we expressed effectors in yeast cells and identified seven effector proteins that interfere with yeast growth. One of the effector proteins, RipAY, was found to share homology with the ChaC family proteins that function as γ-glutamyl cyclotransferases, which degrade glutathione (GSH), a tripeptide that plays important roles in the plant immune system. RipAY significantly inhibited yeast growth and simultaneously induced rapid GSH depletion when expressed in yeast cells. The in vitro GSH degradation activity of RipAY is specifically activated by eukaryotic factors in the yeast and plant extracts. Biochemical purification of the yeast protein identified that RipAY is activated by thioredoxin TRX2. On the other hand, RipAY was not activated by bacterial thioredoxins. Interestingly, RipAY was activated by plant h-type thioredoxins that exist in large amounts in the plant cytosol, but not by chloroplastic m-, f-, x-, y- and z-type thioredoxins, in a thiol-independent manner. The transient expression of RipAY decreased the GSH level in plant cells and affected the flg22-triggered production of reactive oxygen species (ROS) and expression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) marker genes in Nicotiana benthamiana leaves. These results indicate that RipAY is activated by host cytosolic thioredoxins and degrades GSH specifically in plant cells to suppress plant immunity. IMPORTANCE Ralstonia solanacearum is the causal agent of bacterial wilt disease of plants. This pathogen injects virulence effector proteins into host cells to suppress disease resistance responses of plants. In this article, we report a biochemical activity of R. solanacearum effector protein RipAY. RipAY can degrade GSH, a tripeptide that plays important roles in the plant immune system, with its γ-glutamyl cyclotransferase activity. The high GSH degradation activity of RipAY is considered to be a good weapon for this bacterium to suppress plant immunity. However, GSH also plays important roles in bacterial tolerance to various stresses and growth. Interestingly, RipAY has an excellent safety mechanism to prevent unwanted firing of its enzyme activity in bacterial cells because RipAY is specifically activated by host eukaryotic thioredoxins. This study also reveals a novel host plant protein acting as a molecular switch for effector activation.
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Affiliation(s)
- Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), Yoshikawa, Okayama, Japan
| | - Tadashi Hatanaka
- Research Institute for Biological Sciences, Okayama (RIBS), Yoshikawa, Okayama, Japan
| | - Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS), Yoshikawa, Okayama, Japan
| | - Kenji Oda
- Research Institute for Biological Sciences, Okayama (RIBS), Yoshikawa, Okayama, Japan
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Lundgren BR, Connolly MP, Choudhary P, Brookins-Little TS, Chatterjee S, Raina R, Nomura CT. Defining the Metabolic Functions and Roles in Virulence of the rpoN1 and rpoN2 Genes in Ralstonia solanacearum GMI1000. PLoS One 2015; 10:e0144852. [PMID: 26659655 PMCID: PMC4676750 DOI: 10.1371/journal.pone.0144852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/24/2015] [Indexed: 11/18/2022] Open
Abstract
The alternative sigma factor RpoN is a unique regulator found among bacteria. It controls numerous processes that range from basic metabolism to more complex functions such as motility and nitrogen fixation. Our current understanding of RpoN function is largely derived from studies on prototypical bacteria such as Escherichia coli. Bacillus subtilis and Pseudomonas putida. Although the extent and necessity of RpoN-dependent functions differ radically between these model organisms, each bacterium depends on a single chromosomal rpoN gene to meet the cellular demands of RpoN regulation. The bacterium Ralstonia solanacearum is often recognized for being the causative agent of wilt disease in crops, including banana, peanut and potato. However, this plant pathogen is also one of the few bacterial species whose genome possesses dual rpoN genes. To determine if the rpoN genes in this bacterium are genetically redundant and interchangeable, we constructed and characterized ΔrpoN1, ΔrpoN2 and ΔrpoN1 ΔrpoN2 mutants of R. solanacearum GMI1000. It was found that growth on a small range of metabolites, including dicarboxylates, ethanol, nitrate, ornithine, proline and xanthine, were dependent on only the rpoN1 gene. Furthermore, the rpoN1 gene was required for wilt disease on tomato whereas rpoN2 had no observable role in virulence or metabolism in R. solanacearum GMI1000. Interestingly, plasmid-based expression of rpoN2 did not fully rescue the metabolic deficiencies of the ΔrpoN1 mutants; full recovery was specific to rpoN1. In comparison, only rpoN2 was able to genetically complement a ΔrpoN E. coli mutant. These results demonstrate that the RpoN1 and RpoN2 proteins are not functionally equivalent or interchangeable in R. solanacearum GMI1000.
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Affiliation(s)
- Benjamin R. Lundgren
- Department of Chemistry, State University of New York–College of Environmental Science and Forestry, Syracuse, New York, United States of America
| | - Morgan P. Connolly
- Department of Chemistry, State University of New York–College of Environmental Science and Forestry, Syracuse, New York, United States of America
| | - Pratibha Choudhary
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| | - Tiffany S. Brookins-Little
- Department of Chemistry, State University of New York–College of Environmental Science and Forestry, Syracuse, New York, United States of America
| | - Snigdha Chatterjee
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| | - Ramesh Raina
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| | - Christopher T. Nomura
- Department of Chemistry, State University of New York–College of Environmental Science and Forestry, Syracuse, New York, United States of America
- Center for Applied Microbiology, State University of New York–College of Environmental Science and Forestry, Syracuse, New York, United States of America
- * E-mail:
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Mao YH, Ma JC, Li F, Hu Z, Wang HH. Ralstonia solanacearum RSp0194 Encodes a Novel 3-Keto-Acyl Carrier Protein Synthase III. PLoS One 2015; 10:e0136261. [PMID: 26305336 PMCID: PMC4549310 DOI: 10.1371/journal.pone.0136261] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/03/2015] [Indexed: 11/18/2022] Open
Abstract
Fatty acid synthesis (FAS), a primary metabolic pathway, is essential for survival of bacteria. Ralstonia solanacearum, a β-proteobacteria member, causes a bacterial wilt affecting more than 200 plant species, including many economically important plants. However, thus far, the fatty acid biosynthesis pathway of R. solanacearum has not been well studied. In this study, we characterized two forms of 3-keto-ACP synthase III, RsFabH and RsFabW, in R. solanacearum. RsFabH, the homologue of Escherichia coli FabH, encoded by the chromosomal RSc1050 gene, catalyzes the condensation of acetyl-CoA with malonyl-ACP in the initiation steps of fatty acid biosynthesis in vitro. The RsfabH mutant lost de novo fatty acid synthetic ability, and grows in medium containing free fatty acids. RsFabW, a homologue of Pseudomonas aeruginosa PA3286, encoded by a megaplasmid gene, RSp0194, condenses acyl-CoA (C2-CoA to C10-CoA) with malonyl-ACP to produce 3-keto-acyl-ACP in vitro. Although the RsfabW mutant was viable, RsfabW was responsible for RsfabH mutant growth on medium containing free fatty acids. Our results also showed that RsFabW could condense acyl-ACP (C4-ACP to C8-ACP) with malonyl-ACP, to produce 3-keto-acyl-ACP in vitro, which implies that RsFabW plays a special role in fatty acid synthesis of R. solanacearum. All of these data confirm that R. solanacearum not only utilizes acetyl-CoA, but also, utilizes medium-chain acyl-CoAs or acyl-ACPs as primers to initiate fatty acid synthesis.
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Affiliation(s)
- Ya-Hui Mao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Feng Li
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
- * E-mail:
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Li M, Xu P, Zhang W, Zhang Y. [Regulation of rsc1285 gene in type III secretion system in Ralstonia solanacearum]. Wei Sheng Wu Xue Bao 2015; 55:1010-1017. [PMID: 26665598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE Rsc1285 is one of the putative T3SS-regulated factors in Ralstonia solanacearum, and the regulation of Rsc1285 on T3SS and pathogenicity was characterized. METHODS The rsc1285 deletion mutants were constructed by homologous recombination and characterized by complementation. RESULTS The rsc1285 mutant was significantly less virulent than the wild-type strain to infect tomato plants. Rsc1285 controls the expression of hrpB and HrpB-regulating genes, but it is dispensable for the expression of hrpG and prhG. CONCLUSION R. solanacearum uses Rsc1285 to control the T3SS and pathogenicity via a novel pathway, and this finding provides insights into overall infection mode of R. solanacearum.
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Zhang Y, Li M, Luo F. [Advances in studies of the type III secretion system in Ralstonia solanacearum--A review]. Wei Sheng Wu Xue Bao 2015; 55:675-682. [PMID: 26562991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating plant diseases worldwide. The syringe-like type III secretion system (T3SS) plays a crucial role in its pathogenicity. R. solanacearum uses the T3SS to inject effector proteins (Type III effectors) into the cytoplasm of host cells, causing diseases in susceptible plants or triggering the hypersensitive response in resistant plants. In this article we review recent advances in studies of R. solanacearum T3SS and highlight their unique features.
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Liu L, Sun C, Liu S, Chai R, Huang W, Liu X, Tang C, Zhang Y. Bioorganic fertilizer enhances soil suppressive capacity against bacterial wilt of tomato. PLoS One 2015; 10:e0121304. [PMID: 25830639 PMCID: PMC4382293 DOI: 10.1371/journal.pone.0121304] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/30/2015] [Indexed: 11/20/2022] Open
Abstract
Tomato bacterial wilt caused by Ralstonia solanacearum is one of the most destructive soil-borne diseases. Many strategies have been taken to improve soil suppressiveness against this destructive disease, but limited success has been achieved. In this study, a novel bioorganic fertilizer revealed a higher suppressive ability against bacterial wilt compared with several soil management methods in the field over four growing seasons from March 2011 to July 2013. The application of the bioorganic fertilizer significantly (P<0.05) reduced disease incidence of tomato and increased fruit yields in four independent trials. The association among the level of disease incidence, soil physicochemical and biological properties was investigated. The soil treated with the bioorganic fertilizer increased soil pH value, electric conductivity, organic carbon, NH4+-N, NO3--N and available K content, microbial activities and microbial biomass carbon content, which were positively related with soil suppressiveness. Bacterial and actinomycete populations assessed using classical plate counts were highest, whereas R. solanacearum and fungal populations were lowest in soil applied with the bioorganic fertilizer. Microbial community diversity and richness were assessed using denaturing gel gradient electrophoresis profile analysis. The soil treated with the bioorganic fertilizer exhibited higher bacterial community diversity but lower fungal community diversity. Redundancy analysis showed that bacterial community diversity and richness negatively related with bacterial wilt suppressiveness, while fungal community richness positively correlated with R. solanacearum population. We concluded that the alteration of soil physicochemical and biological properties in soil treated with the bioorganic fertilizer induced the soil suppressiveness against tomato bacterial wilt.
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Affiliation(s)
- Lijuan Liu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Chengliang Sun
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Shuangri Liu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Rushan Chai
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Weiqing Huang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Xingxing Liu
- Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Caixian Tang
- Centre for AgriBioscience, La Trobe University, Melbourne Campus, Bundoora, Australia
| | - Yongsong Zhang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
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