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Jiang G, Zhang Y, Chen M, Ramoneda J, Han L, Shi Y, Peyraud R, Wang Y, Shi X, Chen X, Ding W, Jousset A, Hikichi Y, Ohnishi K, Zhao FJ, Xu Y, Shen Q, Dini-Andreote F, Zhang Y, Wei Z. Effects of plant tissue permeability on invasion and population bottlenecks of a phytopathogen. Nat Commun 2024; 15:62. [PMID: 38167266 PMCID: PMC10762237 DOI: 10.1038/s41467-023-44234-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024] Open
Abstract
Pathogen genetic diversity varies in response to environmental changes. However, it remains unclear whether plant barriers to invasion could be considered a genetic bottleneck for phytopathogen populations. Here, we implement a barcoding approach to generate a pool of 90 isogenic and individually barcoded Ralstonia solanacearum strains. We used 90 of these strains to inoculate tomato plants with different degrees of physical permeability to invasion (intact roots, wounded roots and xylem inoculation) and quantify the phytopathogen population dynamics during invasion. Our results reveal that the permeability of plant roots impacts the degree of population bottleneck, genetic diversity, and composition of Ralstonia populations. We also find that selection is the main driver structuring pathogen populations when barriers to infection are less permeable, i.e., intact roots, the removal of root physical and immune barriers results in the predominance of stochasticity in population assembly. Taken together, our study suggests that plant root permeability constitutes a bottleneck for phytopathogen invasion and genetic diversity.
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Affiliation(s)
- Gaofei Jiang
- College of Resources and Environment, College of Plant Protection, Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Yuling Zhang
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Min Chen
- College of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, China
| | - Josep Ramoneda
- Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Liangliang Han
- Department of Biomedical Science, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yu Shi
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, Henan, China
| | - Rémi Peyraud
- iMEAN, Ramonville Saint Agne, Occitanie, FR, France
| | - Yikui Wang
- Vegetable Research Institute, Guangxi Academy of Agricultural Science, Nanning, China
| | - Xiaojun Shi
- College of Resources and Environment, College of Plant Protection, Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Xinping Chen
- College of Resources and Environment, College of Plant Protection, Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Wei Ding
- College of Resources and Environment, College of Plant Protection, Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Alexandre Jousset
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Japan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Japan
| | - Fang-Jie Zhao
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Yangchun Xu
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Qirong Shen
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, China
| | - Francisco Dini-Andreote
- Department of Plant Science & Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
- The One Health Microbiome Center, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Yong Zhang
- College of Resources and Environment, College of Plant Protection, Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China.
- College of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, China.
| | - Zhong Wei
- Key Laboratory of Plant Immunity, Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 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 COMMUNICATIONS 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] [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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3
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Wang K, Yu W, Yu G, Zhang L, Xian L, Wei Y, Perez‐Sancho J, Xue H, Rufian JS, Zhuang H, Kwon C, Macho AP. A bacterial type III effector targets plant vesicle-associated membrane proteins. MOLECULAR PLANT PATHOLOGY 2023; 24:1154-1167. [PMID: 37278116 PMCID: PMC10423332 DOI: 10.1111/mpp.13360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/17/2023] [Accepted: 05/16/2023] [Indexed: 06/07/2023]
Abstract
The soilborne bacterial pathogen Ralstonia solanacearum is one of the most destructive plant pathogens worldwide, and its infection process involves the manipulation of numerous plant cellular functions. In this work, we found that the R. solanacearum effector protein RipD partially suppressed different levels of plant immunity triggered by R. solanacearum elicitors, including specific responses triggered by pathogen-associated molecular patterns and secreted effectors. RipD localized in different subcellular compartments in plant cells, including vesicles, and its vesicular localization was enriched in cells undergoing R. solanacearum infection, suggesting that this specific localization may be particularly relevant during infection. Among RipD-interacting proteins, we identified plant vesicle-associated membrane proteins (VAMPs). We also found that overexpression of Arabidopsis thaliana VAMP721 and VAMP722 in Nicotiana benthamiana leaves promoted resistance to R. solanacearum, and this was abolished by the simultaneous expression of RipD, suggesting that RipD targets VAMPs to contribute to R. solanacearum virulence. Among proteins secreted in VAMP721/722-containing vesicles, CCOAOMT1 is an enzyme required for lignin biosynthesis, and mutation of CCOAOMT1 enhanced plant susceptibility to R. solanacearum. Altogether our results reveal the contribution of VAMPs to plant resistance against R. solanacearum and their targeting by a bacterial effector as a pathogen virulence strategy.
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Affiliation(s)
- Keke Wang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Wenjia Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Gang Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Lu Zhang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Liu Xian
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Yali Wei
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Jessica Perez‐Sancho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Hao Xue
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Jose S. Rufian
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Haiyan Zhuang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
| | - Chian Kwon
- Department of Molecular BiologyDankook UniversityCheonanSouth Korea
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina
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Robic K, Munier E, Effantin G, Lachat J, Naquin D, Gueguen E, Faure D. Dissimilar gene repertoires of Dickeya solani involved in the colonization of lesions and roots of Solanum tuberosum. FRONTIERS IN PLANT SCIENCE 2023; 14:1154110. [PMID: 37223796 PMCID: PMC10202176 DOI: 10.3389/fpls.2023.1154110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/12/2023] [Indexed: 05/25/2023]
Abstract
Dickeya and Pectobacterium species are necrotrophic pathogens that macerate stems (blackleg disease) and tubers (soft rot disease) of Solanum tuberosum. They proliferate by exploiting plant cell remains. They also colonize roots, even if no symptoms are observed. The genes involved in pre-symptomatic root colonization are poorly understood. Here, transposon-sequencing (Tn-seq) analysis of Dickeya solani living in macerated tissues revealed 126 genes important for competitive colonization of tuber lesions and 207 for stem lesions, including 96 genes common to both conditions. Common genes included acr genes involved in the detoxification of plant defense phytoalexins and kduD, kduI, eda (=kdgA), gudD, garK, garL, and garR genes involved in the assimilation of pectin and galactarate. In root colonization, Tn-seq highlighted 83 genes, all different from those in stem and tuber lesion conditions. They encode the exploitation of organic and mineral nutrients (dpp, ddp, dctA, and pst) including glucuronate (kdgK and yeiQ) and synthesis of metabolites: cellulose (celY and bcs), aryl polyene (ape), and oocydin (ooc). We constructed in-frame deletion mutants of bcsA, ddpA, apeH, and pstA genes. All mutants were virulent in stem infection assays, but they were impaired in the competitive colonization of roots. In addition, the ΔpstA mutant was impaired in its capacity to colonize progeny tubers. Overall, this work distinguished two metabolic networks supporting either an oligotrophic lifestyle on roots or a copiotrophic lifestyle in lesions. This work revealed novel traits and pathways important for understanding how the D. solani pathogen efficiently survives on roots, persists in the environment, and colonizes progeny tubers.
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Affiliation(s)
- Kévin Robic
- French Federation of Seed Potato Growers (FN3PT/inov3PT), Paris, France
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Euphrasie Munier
- French Federation of Seed Potato Growers (FN3PT/inov3PT), Paris, France
| | - Géraldine Effantin
- Univ Lyon, Université Claude Bernard Lyon1, CNRS, INSA Lyon, UMR5240 MAP, Lyon, France
| | - Joy Lachat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Erwan Gueguen
- Univ Lyon, Université Claude Bernard Lyon1, CNRS, INSA Lyon, UMR5240 MAP, Lyon, France
| | - Denis Faure
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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Huang M, Tan X, Song B, Wang Y, Cheng D, Wang B, Chen H. Comparative genomic analysis of Ralstonia solanacearum reveals candidate avirulence effectors in HA4-1 triggering wild potato immunity. FRONTIERS IN PLANT SCIENCE 2023; 14:1075042. [PMID: 36909411 PMCID: PMC9997847 DOI: 10.3389/fpls.2023.1075042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Ralstonia solanacearum is the causal agent of potato bacterial wilt, a major potato bacterial disease. Among the pathogenicity determinants, the Type III Secretion System Effectors (T3Es) play a vital role in the interaction. Investigating the avirulent T3Es recognized by host resistance proteins is an effective method to uncover the resistance mechanism of potato against R. solanacearum. Two closely related R. solanacearum strains HA4-1 and HZAU091 were found to be avirulent and highly virulent to the wild potato Solanum albicans 28-1, respectively. The complete genome of HZAU091 was sequenced in this study. HZAU091 and HA4-1 shared over 99.9% nucleotide identity with each other. Comparing genomics of closely related strains provides deeper insights into the interaction between hosts and pathogens, especially the mechanism of virulence. The comparison of type III effector repertoires between HA4-1 and HZAU091 uncovered seven distinct effectors. Two predicted effectors RipA5 and the novel effector RipBS in HA4-1 could significantly reduce the virulence of HZAU091 when they were transformed into HZAU091. Furthermore, the pathogenicity assays of mutated strains HA4-1 ΔRipS6, HA4-1 ΔRipO1, HA4-1 ΔRipBS, and HA4-1 ΔHyp6 uncovered that the absence of these T3Es enhanced the HA4-1 virulence to wild potato S. albicans 28-1. This result indicated that these T3Es may be recognized by S. albicans 28-1 as avirulence proteins to trigger the resistance. In summary, this study provides a foundation to unravel the R. solanacearum-potato interaction and facilitates the development of resistance potato against bacterial wilt.
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Affiliation(s)
- Mengshu Huang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaodan Tan
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
- Guangdong University Key Laboratory for Sustainable Control of Fruit and Vegetable Diseases and Pests & Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China, Ministry of Agriculture and Rural Affairs, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Botao Song
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yuqi Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dong Cheng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Bingsen Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Huilan Chen
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, Hubei, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, Hubei, China
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6
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Rivera-Zuluaga K, Hiles R, Barua P, Caldwell D, Iyer-Pascuzzi AS. Getting to the root of Ralstonia invasion. Semin Cell Dev Biol 2022; 148-149:3-12. [PMID: 36526528 DOI: 10.1016/j.semcdb.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/16/2022]
Abstract
Plant diseases caused by soilborne pathogens are a major limiting factor in crop production. Bacterial wilt disease, caused by soilborne bacteria in the Ralstonia solanacearum Species Complex (Ralstonia), results in significant crop loss throughout the world. Ralstonia invades root systems and colonizes plant xylem, changing plant physiology and ultimately causing plant wilting in susceptible varieties. Elucidating how Ralstonia invades and colonizes plants is central to developing strategies for crop protection. Here we review Ralstonia pathogenesis from root detection and attachment, early root colonization, xylem invasion and subsequent wilting. We focus primarily on studies in tomato from the last 5-10 years. Recent work has identified elegant mechanisms Ralstonia uses to adapt to the plant xylem, and has discovered new genes that function in Ralstonia fitness in planta. A picture is emerging of an amazingly versatile pathogen that uses multiple strategies to make its surrounding environment more hospitable and can adapt to new environments.
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An Y, Chen J, Xu Z, Ouyang X, Cao P, Wang R, Liu P, Zhang M. Three amino acid residues are required for the recognition of Ralstonia solanacearum RipTPS in Nicotiana tabacum. FRONTIERS IN PLANT SCIENCE 2022; 13:1040826. [PMID: 36311066 PMCID: PMC9606615 DOI: 10.3389/fpls.2022.1040826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 09/27/2022] [Indexed: 06/10/2023]
Abstract
Ralstonia solanacearum causes devastating diseases in a wide range of economically important crops. It secretes a large number of virulence factors, also known as effectors, to promote its infection, and some of them are recognized when the host plant contains corresponding resistance genes. In this study we showed that a type III effector RipTPS from the avirulent R. solanacearum strain GMI1000 (RipTPSG) specifically induced cell death in Nicotiana tabacum, but not in Nicotiana benthamiana, whereas the RipTPS homolog in the virulent strain CQPS-1 (RipTPSC) induced cell death in neither N. tabacum nor N. benthamiana. These results indicated that RipTPSG is recognized in N. tabacum. Expression of RipTPSG induced upregulation of hypersensitive response (HR) -related genes in N. tabacum. The virulence of CQPS-1 was reduced when RipTPSG was genetically introduced into CQPS-1, further confirming that RipTPSG functions as an avirulence determinant. Protein sequence alignment indicated that there are only three amino acid polymorphisms between RipTPSG and RipTPSC. Site-directed mutagenesis analyses confirmed that the three amino acid residues are jointly required for the recognition of RipTPSG in N. tabacum. Expression of either RipTPSG or RipTPSC suppressed flg22-triggered reactive oxygen species (ROS) burst in N. benthamiana, suggesting that RipTPS contributes to pathogen virulence. Mutating the conserved residues in RipTPS's trehalose-phosphate synthase (TPS) domain did not block its HR induction and defense suppression activity, indicating that the TPS activity is not required for RipTPS's avirulence and virulence function.
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Affiliation(s)
- Yuyan An
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Jialan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Zhangyan Xu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Xue Ouyang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | - Peng Cao
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Rongbo Wang
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Peiqing Liu
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Meixiang Zhang
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi’an, China
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8
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Cao P, Chen J, Wang R, Zhao M, Zhang S, An Y, Liu P, Zhang M. A conserved type III effector RipB is recognized in tobacco and contributes to Ralstonia solanacearum virulence in susceptible host plants. Biochem Biophys Res Commun 2022; 631:18-24. [PMID: 36162325 DOI: 10.1016/j.bbrc.2022.09.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 11/02/2022]
Abstract
Ralstonia solanacearum, the causal agent of bacterial wilt, causes devastating diseases in a wide range of plants including potato, tomato, pepper and tobacco. The pathogen delivers approximately 70 type III effectors (T3Es) into plant cells during infection. In this study, we confirmed that a T3E RipB is recognized in tobacco. We further demonstrated that RipB is conserved among R. solanacearum isolates and five different ripB alleles are all recognized in tobacco. The ripB from GMI1000 was transformed into susceptible host Arabidopsis, and a defect in root development was observed in ripB-transgenic plants. Pathogen inoculation assays showed that ripB expression promoted plant susceptibility to R. solanacearum infection, indicating that RipB contributes to pathogen virulence in Arabidopsis. Expression of ripB in roq1 mutant partially suppressed reactive oxygen species production, confirming that RipB interferes with plant basal defense. Interestingly, ripB expression promoted cytokinin-related gene expression in Arabidopsis, suggesting a role of cytokinin signaling pathway in plant-R. solanacearum interactions. Finally, RipB harbors potential 14-3-3 binding motifs, but the associations between RipB and 14-3-3 proteins were undetectable in yeast two-hybrid assay. Together, our results demonstrate that multiple ripB alleles are recognized in Nicotiana, and RipB suppresses basal defense in susceptible host to promote R. solanacearum infection.
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Affiliation(s)
- Peng Cao
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Jialan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Rongbo Wang
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fuzhou, 350013, China
| | - Mengwei Zhao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shuangxi Zhang
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Yuyan An
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Peiqing Liu
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fuzhou, 350013, China.
| | - Meixiang Zhang
- National Engineering Laboratory for Endangered Medicinal Resource Development in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, China.
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9
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Luneau JS, Noël LD, Lauber E, Boulanger A. A β-glucuronidase (GUS) Based Bacterial Competition Assay to Assess Fine Differencesin Fitness during Plant Infection. Bio Protoc 2022; 12:e3776. [PMID: 35991161 PMCID: PMC9382408 DOI: 10.21769/bioprotoc.3776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/03/2020] [Accepted: 06/11/2020] [Indexed: 12/29/2022] Open
Abstract
Competition assays are a simple phenotyping strategy that confront two bacterial strains to evaluate their relative fitness. Because they are more accurate than single-strain growth assays, competition assays can be used to highlight slight differences that would not otherwise be detectable. In the frame of host-pathogens interactions, they can be very useful to study the contribution of individual bacterial genes to bacterial fitness and lead to the identification of new adaptive traits. Here, we describe how to perform such competition assays by taking the example of the model phytopathogenic bacterium Xanthomonas campestris pv. campestris during infection of the mesophyll of its cauliflower host. This phenotypic assay is based on the use of a Competitive Index (CI) that compares the relative abundance of co-inoculated strains before and after inoculation. Since multiplication is a direct proxy for bacterial fitness, the evolution of the ratio between both strains in the mixed population is a direct way to assess differences in fitness in a given environment. In this protocol, we exploit the blue staining of GUS-expressing bacteria to count blue vs. white colonies on plates and estimate the competitiveness of the strains of interest in plant mesophyll.
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Affiliation(s)
- Julien S. Luneau
- Laboratory of Plant-Microbes Interactions, Université de Toulouse, INRAE, CNRS, UPS, Castanet-Tolosan, France
| | - Laurent D. Noël
- Laboratory of Plant-Microbes Interactions, Université de Toulouse, INRAE, CNRS, UPS, Castanet-Tolosan, France
| | - Emmanuelle Lauber
- Laboratory of Plant-Microbes Interactions, Université de Toulouse, INRAE, CNRS, UPS, Castanet-Tolosan, France
| | - Alice Boulanger
- Laboratory of Plant-Microbes Interactions, Université de Toulouse, INRAE, CNRS, UPS, Castanet-Tolosan, France,
*For correspondence:
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10
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Liu Y, Tan X, Pan Y, Yu J, Du Y, Liu X, Ding W. Mutation in phcA Enhanced the Adaptation of Ralstonia solanacearum to Long-Term Acid Stress. Front Microbiol 2022; 13:829719. [PMID: 35722283 PMCID: PMC9204249 DOI: 10.3389/fmicb.2022.829719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial wilt, caused by the plant pathogen Ralstonia solanacearum, occurs more severely in acidified soil according to previous reports. However, R. solanacearum cannot grow well in acidic environments under barren nutrient culture conditions, especially when the pH is lower than 5. With the worsening acidification of farmland, further determination of how R. solanacearum adapts to the long-term acidic environment is worthwhile. In this study, experimental evolution was applied to evaluate the adaptability and mechanism of the R. solanacearum experimental population responding to long-term acid stress. We chose the CQPS-1 strain as the ancestor, and minimal medium (MM medium) with different pH values as the culture environment to simulate poor soil. After 1500 generations of serial passage experiments in pH 4.9 MM, acid-adapted experimental strains (denoted as C49 strains) were obtained, showing significantly higher growth rates than the growth rates of control experimental strains (serial passage experiment in pH 6.5 MM, denoted as C65 strains). Competition experiments showed that the competitive indices (CIs) of all selected clones from C49 strains were superior to the ancestor in acidic environment competitiveness. Based on the genome variation analysis and functional verification, we confirmed that loss of function in the phcA gene was associated with the acid fitness gain of R. solanacearum, which meant that the inactivation of the PhcA regulator caused by gene mutation mediated the population expansion of R. solanacearum when growing in an acidic stress environment. Moreover, the swimming motility of acid evolution strains and the phcA deletion mutant was significantly enhanced compared to CQPS-1. This work provided evidence for understanding the adaptive strategy of R. solanacearum to the long-term acidic environment.
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Affiliation(s)
- Ying Liu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Xi Tan
- College of Plant Protection, Southwest University, Chongqing, China
| | - Yanxin Pan
- College of Plant Protection, Southwest University, Chongqing, China
| | - Jiamin Yu
- Sichuan Company of China National Tobacco Corporation, Chengdu, China
| | - Yiran Du
- College of Plant Protection, Southwest University, Chongqing, China
| | - Xiaojiao Liu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Wei Ding
- College of Plant Protection, Southwest University, Chongqing, China
- *Correspondence: Wei Ding,
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11
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Tan X, Dai X, Chen T, Wu Y, Yang D, Zheng Y, Chen H, Wan X, Yang Y. Complete Genome Sequence Analysis of Ralstonia solanacearum Strain PeaFJ1 Provides Insights Into Its Strong Virulence in Peanut Plants. Front Microbiol 2022; 13:830900. [PMID: 35273586 PMCID: PMC8904134 DOI: 10.3389/fmicb.2022.830900] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/12/2022] [Indexed: 11/22/2022] Open
Abstract
The bacterial wilt of peanut (Arachis hypogaea L.) caused by Ralstonia solanacearum is a devastating soil-borne disease that seriously restricted the world peanut production. However, the molecular mechanism of R. solanacearum–peanut interaction remains largely unknown. We found that R. solanacearum HA4-1 and PeaFJ1 isolated from peanut plants showed different pathogenicity by inoculating more than 110 cultivated peanuts. Phylogenetic tree analysis demonstrated that HA4-1 and PeaFJ1 both belonged to phylotype I and sequevar 14M, which indicates a high degree of genomic homology between them. Genomic sequencing and comparative genomic analysis of PeaFJ1 revealed 153 strain-specific genes compared with HA4-1. The PeaFJ1 strain-specific genes consisted of diverse virulence-related genes including LysR-type transcriptional regulators, two-component system-related genes, and genes contributing to motility and adhesion. In addition, the repertoire of the type III effectors of PeaFJ1 was bioinformatically compared with that of HA4-1 to find the candidate effectors responsible for their different virulences. There are 79 effectors in the PeaFJ1 genome, only 4 of which are different effectors compared with HA4-1, including RipS4, RipBB, RipBS, and RS_T3E_Hyp6. Based on the virulence profiles of the two strains against peanuts, we speculated that RipS4 and RipBB are candidate virulence effectors in PeaFJ1 while RipBS and RS_T3E_Hyp6 are avirulence effectors in HA4-1. In general, our research greatly reduced the scope of virulence-related genes and made it easier to find out the candidates that caused the difference in pathogenicity between the two strains. These results will help to reveal the molecular mechanism of peanut–R. solanacearum interaction and develop targeted control strategies in the future.
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Affiliation(s)
- Xiaodan Tan
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Xiaoqiu Dai
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Ting Chen
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Yushuang Wu
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Dong Yang
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Yixiong Zheng
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Huilan Chen
- Key Laboratory of Horticultural Plant Biology (HZAU), Ministry of Education, Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
| | - Xiaorong Wan
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Yong Yang
- Guangzhou Key Laboratory for Research and Development of Crop Germplasm Resources, Zhongkai University of Agriculture and Engineering, Guangzhou, China
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12
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Torres M, Jiquel A, Jeanne E, Naquin D, Dessaux Y, Faure D. Agrobacterium tumefaciens fitness genes involved in the colonization of plant tumors and roots. THE NEW PHYTOLOGIST 2022; 233:905-918. [PMID: 34655498 DOI: 10.1111/nph.17810] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Agrobacterium tumefaciens colonizes the galls (plant tumors) it causes, and the roots of host and nonhost plants. Transposon-sequencing (Tn-Seq) was used to discover A.tumefaciens genes involved in reproductive success (fitness genes) on Solanum lycopersicum and Populus trichocarpa tumors and S.lycopersicum and Zea mays roots. The identified fitness genes represent 3-8% of A. tumefaciens genes and contribute to carbon and nitrogen metabolism, synthesis and repair of DNA, RNA and proteins and envelope-associated functions. Competition assays between 12 knockout mutants and wild-type confirmed the involvement of 10 genes (trpB, hisH, metH, cobN, ntrB, trxA, nrdJ, kamA, exoQ, wbbL) in A.tumefaciens fitness under both tumor and root conditions. The remaining two genes (fecA, noxA) were important in tumors only. None of these mutants was nonpathogenic, but four (hisH, trpB, exoQ, ntrB) exhibited impaired virulence. Finally, we used this knowledge to search for chemical and biocontrol treatments that target some of the identified fitness pathways and report reduced tumorigenesis and impaired establishment of A.tumefaciens on tomato roots using tannic acid or Pseudomonas protegens, which affect iron assimilation. This work revealed A.tumefaciens pathways that contribute to its competitive survival in plants and highlights a strategy to identify plant protection approaches against this pathogen.
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Affiliation(s)
- Marta Torres
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91190, France
| | - Audren Jiquel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91190, France
| | - Etienne Jeanne
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91190, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91190, France
| | - Yves Dessaux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91190, France
| | - Denis Faure
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, 91190, France
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13
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Wang Y, Xian L, Yu G, Macho AP. Tomato Stem Injection for the Precise Assessment of Ralstonia solanacearum Fitness in Planta. Bio Protoc 2021; 11:e4134. [PMID: 34541051 PMCID: PMC8413648 DOI: 10.21769/bioprotoc.4134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 11/02/2022] Open
Abstract
Ralstonia solanacearum is a soil-borne pathogen with worldwide distribution that causes bacterial wilt disease in more than 250 plant species. R. solanacearum invades plants through the roots, reaches the vascular system, and colonizes the whole plant by moving through the xylem, where it eventually replicates rapidly, causing plant death. Usual assays to measure the virulence of R. solanacearum under laboratory conditions rely on soil-drenching inoculation followed by observation and scoring of disease symptoms. Here, we describe a protocol to assess the replication of R. solanacearum following injection into tomato stems. This protocol includes four major steps: 1) growth of tomato plants; 2) R. solanacearum injection into tomato stems; 3) collection of tomato xylem samples and bacterial quantitation; and 4) data analysis and representation. This method bypasses the natural penetration process of the pathogen, thus minimizing variation associated with stochastic events during bacterial invasion, and provides a sensitive and accurate measurement of bacterial fitness inside xylem vessels.
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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
| | - Liu Xian
- 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
| | - Gang Yu
- 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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Kumar CMS, Chugh K, Dutta A, Mahamkali V, Bose T, Mande SS, Mande SC, Lund PA. Chaperonin Abundance Enhances Bacterial Fitness. Front Mol Biosci 2021; 8:669996. [PMID: 34381811 PMCID: PMC8350394 DOI: 10.3389/fmolb.2021.669996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 07/01/2021] [Indexed: 12/12/2022] Open
Abstract
The ability of chaperonins to buffer mutations that affect protein folding pathways suggests that their abundance should be evolutionarily advantageous. Here, we investigate the effect of chaperonin overproduction on cellular fitness in Escherichia coli. We demonstrate that chaperonin abundance confers 1) an ability to tolerate higher temperatures, 2) improved cellular fitness, and 3) enhanced folding of metabolic enzymes, which is expected to lead to enhanced energy harvesting potential.
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Affiliation(s)
- C M Santosh Kumar
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Kritika Chugh
- Department of Biotechnology and Bioinformatics, University of Rajasthan, Jaipur, India
| | - Anirban Dutta
- TCS Research, Tata Consultancy Services Ltd., Pune, India
| | - Vishnuvardhan Mahamkali
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
| | - Tungadri Bose
- TCS Research, Tata Consultancy Services Ltd., Pune, India
| | | | - Shekhar C Mande
- Laboratory of Structural Biology, National Centre for Cell Science (NCCS), Pune, India
| | - Peter A Lund
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
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15
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Gopalan-Nair R, Jardinaud MF, Legrand L, Landry D, Barlet X, Lopez-Roques C, Vandecasteele C, Bouchez O, Genin S, Guidot A. Convergent Rewiring of the Virulence Regulatory Network Promotes Adaptation of Ralstonia solanacearum on Resistant Tomato. Mol Biol Evol 2021; 38:1792-1808. [PMID: 33306125 PMCID: PMC8097285 DOI: 10.1093/molbev/msaa320] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The evolutionary and adaptive potential of a pathogen is a key determinant for successful host colonization and proliferation but remains poorly known for most of the pathogens. Here, we used experimental evolution combined with phenotyping, genomics, and transcriptomics to estimate the adaptive potential of the bacterial plant pathogen Ralstonia solanacearum to overcome the quantitative resistance of the tomato cultivar Hawaii 7996. After serial passaging over 300 generations, we observed pathogen adaptation to within-plant environment of the resistant cultivar but no plant resistance breakdown. Genomic sequence analysis of the adapted clones revealed few genetic alterations, but we provide evidence that all but one were gain of function mutations. Transcriptomic analyses revealed that even if different adaptive events occurred in independently evolved clones, there is convergence toward a global rewiring of the virulence regulatory network as evidenced by largely overlapping gene expression profiles. A subset of four transcription regulators, including HrpB, the activator of the type 3 secretion system regulon and EfpR, a global regulator of virulence and metabolic functions, emerged as key nodes of this regulatory network that are frequently targeted to redirect the pathogen’s physiology and improve its fitness in adverse conditions. Significant transcriptomic variations were also detected in evolved clones showing no genomic polymorphism, suggesting that epigenetic modifications regulate expression of some of the virulence network components and play a major role in adaptation as well.
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Affiliation(s)
| | | | - Ludovic Legrand
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - David Landry
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Xavier Barlet
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | | | | | - Olivier Bouchez
- GeT-PlaGe, Genotoul, INRAE, US 1426, Castanet-Tolosan, France
| | - Stéphane Genin
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Alice Guidot
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
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16
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Schreiber KJ, Chau-Ly IJ, Lewis JD. What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins. Microorganisms 2021; 9:1029. [PMID: 34064647 PMCID: PMC8150971 DOI: 10.3390/microorganisms9051029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 01/05/2023] Open
Abstract
Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.
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Affiliation(s)
- Karl J. Schreiber
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Ilea J. Chau-Ly
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Jennifer D. Lewis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
- Plant Gene Expression Center, United States Department of Agriculture, University of California, Berkeley, CA 94710, USA
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17
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Landry D, González‐Fuente M, Deslandes L, Peeters N. The large, diverse, and robust arsenal of Ralstonia solanacearum type III effectors and their in planta functions. MOLECULAR PLANT PATHOLOGY 2020; 21:1377-1388. [PMID: 32770627 PMCID: PMC7488467 DOI: 10.1111/mpp.12977] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/15/2020] [Accepted: 06/22/2020] [Indexed: 05/25/2023]
Abstract
The type III secretion system with its delivered type III effectors (T3Es) is one of the main virulence determinants of Ralstonia solanacearum, a worldwide devastating plant pathogenic bacterium affecting many crop species. The pan-effectome of the R. solanacearum species complex has been exhaustively identified and is composed of more than 100 different T3Es. Among the reported strains, their content ranges from 45 to 76 T3Es. This considerably large and varied effectome could be considered one of the factors contributing to the wide host range of R. solanacearum. In order to understand how R. solanacearum uses its T3Es to subvert the host cellular processes, many functional studies have been conducted over the last three decades. It has been shown that R. solanacearum effectors, as those from other plant pathogens, can suppress plant defence mechanisms, modulate the host metabolism, or avoid bacterial recognition through a wide variety of molecular mechanisms. R. solanacearum T3Es can also be perceived by the plant and trigger immune responses. To date, the molecular mechanisms employed by R. solanacearum T3Es to modulate these host processes have been described for a growing number of T3Es, although they remain unknown for the majority of them. In this microreview, we summarize and discuss the current knowledge on the characterized R. solanacearum species complex T3Es.
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Affiliation(s)
- David Landry
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
| | - Manuel González‐Fuente
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
| | - Laurent Deslandes
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
| | - Nemo Peeters
- Laboratoire des Interactions Plantes Micro‐organismes (LIPM)INRAE, CNRS, Université de ToulouseCastanet‐TolosanFrance
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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] [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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Zarkani AA, López-Pagán N, Grimm M, Sánchez-Romero MA, Ruiz-Albert J, Beuzón CR, Schikora A. Salmonella Heterogeneously Expresses Flagellin during Colonization of Plants. Microorganisms 2020; 8:microorganisms8060815. [PMID: 32485895 PMCID: PMC7355505 DOI: 10.3390/microorganisms8060815] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/19/2022] Open
Abstract
Minimally processed or fresh fruits and vegetables are unfortunately linked to an increasing number of food-borne diseases, such as salmonellosis. One of the relevant virulence factors during the initial phases of the infection process is the bacterial flagellum. Although its function is well studied in animal systems, contradictory results have been published regarding its role during plant colonization. In this study, we tested the hypothesis that Salmonella's flagellin plays a versatile function during the colonization of tomato plants. We have assessed the persistence in plant tissues of a Salmonella enterica wild type strain, and of a strain lacking the two flagellins, FljB and FliC. We detected no differences between these strains concerning their respective abilities to reach distal, non-inoculated parts of the plant. Analysis of flagellin expression inside the plant, at both the population and single cell levels, shows that the majority of bacteria down-regulate flagellin production, however, a small fraction of the population continues to express flagellin at a very high level inside the plant. This heterogeneous expression of flagellin might be an adaptive strategy to the plant environment. In summary, our study provides new insights on Salmonella adaption to the plant environment through the regulation of flagellin expression.
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Affiliation(s)
- Azhar A. Zarkani
- Julius Kühn-Institut Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (A.A.Z.); (M.G.)
- Department of Biotechnology, College of Science, University of Baghdad, 10071 Baghdad, Iraq
| | - Nieves López-Pagán
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Dpto. Biología Celular, Genética y Fisiología, Campus de Teatinos, 29071 Malaga, Spain; (N.L.-P.); (J.R.-A.); (C.R.B.)
| | - Maja Grimm
- Julius Kühn-Institut Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (A.A.Z.); (M.G.)
| | - María Antonia Sánchez-Romero
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Seville, Spain;
- Current address: Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, Calle Profesor García González 2, 41012 Seville, Spain
| | - Javier Ruiz-Albert
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Dpto. Biología Celular, Genética y Fisiología, Campus de Teatinos, 29071 Malaga, Spain; (N.L.-P.); (J.R.-A.); (C.R.B.)
| | - Carmen R. Beuzón
- Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Dpto. Biología Celular, Genética y Fisiología, Campus de Teatinos, 29071 Malaga, Spain; (N.L.-P.); (J.R.-A.); (C.R.B.)
| | - Adam Schikora
- Julius Kühn-Institut Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (A.A.Z.); (M.G.)
- Correspondence:
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20
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Wu D, von Roepenack-Lahaye E, Buntru M, de Lange O, Schandry N, Pérez-Quintero AL, Weinberg Z, Lowe-Power TM, Szurek B, Michael AJ, Allen C, Schillberg S, Lahaye T. A Plant Pathogen Type III Effector Protein Subverts Translational Regulation to Boost Host Polyamine Levels. Cell Host Microbe 2019; 26:638-649.e5. [DOI: 10.1016/j.chom.2019.09.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/21/2019] [Accepted: 09/23/2019] [Indexed: 01/21/2023]
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Perez-Quintero AL, Szurek B. A Decade Decoded: Spies and Hackers in the History of TAL Effectors Research. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:459-481. [PMID: 31387457 DOI: 10.1146/annurev-phyto-082718-100026] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Transcription activator-like effectors (TALEs) from the genus Xanthomonas are proteins with the remarkable ability to directly bind the promoters of genes in the plant host to induce their expression, which often helps bacterial colonization. Metaphorically, TALEs act as spies that infiltrate the plant disguised as high-ranking civilians (transcription factors) to trick the plant into activating weak points that allow an invasion. Current knowledge of how TALEs operate allows researchers to predict their activity (counterespionage) and exploit their function, engineering them to do our bidding (a Manchurian agent). This has been possible thanks particularly to the discovery of their DNA binding mechanism, which obeys specific amino acid-DNA correspondences (the TALE code). Here, we review the history of how researchers discovered the way these proteins work and what has changed in the ten years since the discovery of the code. Recommended music for reading this review can be found in the Supplemental Material.
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Affiliation(s)
- Alvaro L Perez-Quintero
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado 80523-1177, USA;
- IRD, CIRAD, Université Montpellier, IPME, 34000 Montpellier, France;
| | - Boris Szurek
- IRD, CIRAD, Université Montpellier, IPME, 34000 Montpellier, France;
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Tan X, Qiu H, Li F, Cheng D, Zheng X, Wang B, Huang M, Li W, Li Y, Sang K, Song B, Du J, Chen H, Xie C. Complete Genome Sequence of Sequevar 14M Ralstonia solanacearum Strain HA4-1 Reveals Novel Type III Effectors Acquired Through Horizontal Gene Transfer. Front Microbiol 2019; 10:1893. [PMID: 31474968 PMCID: PMC6703095 DOI: 10.3389/fmicb.2019.01893] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/31/2019] [Indexed: 01/08/2023] Open
Abstract
Ralstonia solanacearum, which causes bacterial wilt in a broad range of plants, is considered a "species complex" due to its significant genetic diversity. Recently, we have isolated a new R. solanacearum strain HA4-1 from Hong'an county in Hubei province of China and identified it being phylotype I, sequevar 14M (phylotype I-14M). Interestingly, we found that it can cause various disease symptoms among different potato genotypes and display different pathogenic behavior compared to a phylogenetically related strain, GMI1000. To dissect the pathogenic mechanisms of HA4-1, we sequenced its whole genome by combined sequencing technologies including Illumina HiSeq2000, PacBio RS II, and BAC-end sequencing. Genome assembly results revealed the presence of a conventional chromosome, a megaplasmid as well as a 143 kb plasmid in HA4-1. Comparative genome analysis between HA4-1 and GMI1000 shows high conservation of the general virulence factors such as secretion systems, motility, exopolysaccharides (EPS), and key regulatory factors, but significant variation in the repertoire and structure of type III effectors, which could be the determinants of their differential pathogenesis in certain potato species or genotypes. We have identified two novel type III effectors that were probably acquired through horizontal gene transfer (HGT). These novel R. solanacearum effectors display homology to several YopJ and XopAC family members. We named them as RipBR and RipBS. Notably, the copy of RipBR on the plasmid is a pseudogene, while the other on the megaplasmid is normal. For RipBS, there are three copies located in the megaplasmid and plasmid, respectively. Our results have not only enriched the genome information on R. solanacearum species complex by sequencing the first sequevar 14M strain and the largest plasmid reported in R. solanacearum to date but also revealed the variation in the repertoire of type III effectors. This will greatly contribute to the future studies on the pathogenic evolution, host adaptation, and interaction between R. solanacearum and potato.
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Affiliation(s)
- Xiaodan Tan
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Huishan Qiu
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Feng Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Dong Cheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Xueao Zheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Bingsen Wang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Mengshu Huang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Wenhao Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Yanping Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Kangqi Sang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
| | - Botao Song
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Juan Du
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Huilan Chen
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
| | - Conghua Xie
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
- National Center for Vegetable Improvement (Central China), Wuhan, China
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Liu L, Lu DQ, Xu J, Luo HL, Li AX. Development of attenuated erythromycin-resistant Streptococcus agalactiae vaccine for tilapia (Oreochromis niloticus) culture. JOURNAL OF FISH DISEASES 2019; 42:693-701. [PMID: 30893488 DOI: 10.1111/jfd.12977] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 06/09/2023]
Abstract
Streptococcus agalactiae is an important pathogen in fish, causing great losses of intensive tilapia farming. To develop a potential live attenuated vaccine, a re-attenuated S. agalactiae (named TFJ-ery) was developed from a natural low-virulence S. agalactiae strain TFJ0901 through selection of resistance to erythromycin. The biological characteristics, virulence, stability and the immunization protective efficacy to tilapia of TFJ-ery were determined. The results indicated that TFJ-ery grew at a slower rate than TFJ0901. The capsule thickness of TFJ-ery was significantly less (p < 0.05) than TFJ0901. When Nile tilapia were intraperitoneally (IP) injected with TFJ-ery, the mortality of fish was decreased than that injected with TFJ0901. The RPS of fish immunized with TFJ-ery at a dose of 5.0 × 107 CFU was 95.00%, 93.02% and 100.00% at 4, 8 and 16 weeks post-vaccination, respectively. ELISA results showed that the vaccinated fish produced significantly higher (p < 0.05) antibody titres compared to those of control at 2 or 4 weeks post-vaccination. Taken together, our results suggest that erythromycin could be used to attenuate S. agalactiae, and TFJ-ery is a potent attenuated vaccine candidate to protect tilapia against S. agalactiae infections.
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Affiliation(s)
- Ling Liu
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Dan-Qi Lu
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Jun Xu
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Heng-Li Luo
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - An-Xing Li
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, PR China
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24
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Zheng X, Li X, Wang B, Cheng D, Li Y, Li W, Huang M, Tan X, Zhao G, Song B, Macho AP, Chen H, Xie C. A systematic screen of conserved Ralstonia solanacearum effectors reveals the role of RipAB, a nuclear-localized effector that suppresses immune responses in potato. MOLECULAR PLANT PATHOLOGY 2019; 20:547-561. [PMID: 30499228 PMCID: PMC6637881 DOI: 10.1111/mpp.12774] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Both Solanum tuberosum and Ralstonia solanacearum phylotype IIB originated in South America and share a long-term co-evolutionary history. However, our knowledge of potato bacterial wilt pathogenesis is scarce as a result of the technical difficulties of potato plant manipulation. Thus, we established a multiple screening system (virulence screen of effector mutants in potato, growth inhibition of yeast and transient expression in Nicotiana benthamiana) of core type III effectors (T3Es) of a major potato pathovar of phylotype IIB, to provide more research perspectives and biological tools. Using this system, we identified four effectors contributing to virulence during potato infection, with two exhibiting multiple phenotypes in two other systems, including RipAB. Further study showed that RipAB is an unknown protein with a nuclear localization signal (NLS). Furthermore, we generated a ripAB complementation strain and transgenic ripAB-expressing potato plants, and subsequent virulence assays confirmed that R. solanacearum requires RipAB for full virulence. Compared with wild-type potato, transcriptomic analysis of transgenic ripAB-expressing potato plants showed a significant down-regulation of Ca2+ signalling-related genes in the enriched Plant-Pathogen Interaction (PPI) gene ontology (GO) term. We further verified that, during infection, RipAB is required for the down-regulation of four Ca2+ sensors, Stcml5, Stcml23, Stcml-cast and Stcdpk2, and a Ca2+ transporter, Stcngc1. Further evidence showed that the immune-associated reactive oxygen species (ROS) burst is attenuated in ripAB transgenic potato plants. In conclusion, a systematic screen of conserved R. solanacearum effectors revealed an important role for RipAB, which interferes with Ca2+ -dependent gene expression to promote disease development in potato.
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Affiliation(s)
- Xueao Zheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Xiaojing Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
- Key Laboratory of Plant Resources, Institute of BotanyChinese Academy of SciencesBeijing100093China
| | - Bingsen Wang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Dong Cheng
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Yanping Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Wenhao Li
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Mengshu Huang
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Xiaodan Tan
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Guozhen Zhao
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Botao Song
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
- Key Laboratory of Horticultural Plant Biology, Ministry of EducationHuazhong Agricultural UniversityWuhan430070China
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological SciencesChinese Academy of SciencesShanghai201602China
| | - Huilan Chen
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
| | - Conghua Xie
- Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China
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Gonzalez-Mula A, Lachat J, Mathias L, Naquin D, Lamouche F, Mergaert P, Faure D. The biotroph Agrobacterium tumefaciens thrives in tumors by exploiting a wide spectrum of plant host metabolites. THE NEW PHYTOLOGIST 2019; 222:455-467. [PMID: 30447163 DOI: 10.1111/nph.15598] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/03/2018] [Indexed: 05/12/2023]
Abstract
Agrobacterium tumefaciens is a niche-constructing biotroph that exploits host plant metabolites. We combined metabolomics, transposon-sequencing (Tn-seq), transcriptomics, and reverse genetics to characterize A. tumefaciens pathways involved in the exploitation of resources from the Solanum lycopersicum host plant. Metabolomics of healthy stems and plant tumors revealed the common (e.g. sucrose, glutamate) and enriched (e.g. opines, γ-aminobutyric acid (GABA), γ-hydroxybutyric acid (GHB), pyruvate) metabolites that A. tumefaciens could use as nutrients. Tn-seq and transcriptomics pinpointed the genes that are crucial and/or upregulated when the pathogen grew on either sucrose (pgi, kdgA, pycA, cisY) or GHB (blcAB, pckA, eno, gpsA) as a carbon source. While sucrose assimilation involved the Entner-Doudoroff and tricarboxylic acid (TCA) pathways, GHB degradation required the blc genes, TCA cycle, and gluconeogenesis. The tumor-enriched metabolite pyruvate is at the node connecting these pathways. Using reverse genetics, we showed that the blc, pckA, and pycA loci were important for aggressiveness (tumor weight), proliferation (bacterial charge), and/or fitness (competition between the constructed mutants and wild-type) of A. tumefaciens in plant tumors. This work highlighted how a biotroph mobilizes its central metabolism for exploiting a wide diversity of resources in a plant host. It further shows the complementarity of functional genome-wide scans by transcriptomics and Tn-seq to decipher the lifestyle of a plant pathogen.
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Affiliation(s)
- Almudena Gonzalez-Mula
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
| | - Joy Lachat
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
| | - Léo Mathias
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
| | - Delphine Naquin
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
| | - Florian Lamouche
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
| | - Peter Mergaert
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
| | - Denis Faure
- Institute for Integrative Biology of the Cell (I2BC), CNRS CEA University Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, F-91190, France
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Baldeweg F, Hoffmeister D, Nett M. A genomics perspective on natural product biosynthesis in plant pathogenic bacteria. Nat Prod Rep 2019; 36:307-325. [DOI: 10.1039/c8np00025e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review summarizes findings from genomics-inspired natural product research in plant pathogenic bacteria and discusses emerging trends in this field.
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Affiliation(s)
- Florian Baldeweg
- Department of Pharmaceutical Microbiology at the Hans Knöll Institute
- Friedrich-Schiller-University Jena
- 07745 Jena
- Germany
| | - Dirk Hoffmeister
- Department of Pharmaceutical Microbiology at the Hans Knöll Institute
- Friedrich-Schiller-University Jena
- 07745 Jena
- Germany
| | - Markus Nett
- Department of Biochemical and Chemical Engineering
- TU Dortmund University
- 44227 Dortmund
- Germany
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27
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Singh N, Kumar R, Ray SK. An Innovative Approach to Study Ralstonia solanacearum Pathogenicity in 6 to 7 Days Old Tomato Seedlings by Root Dip Inoculation. Bio Protoc 2018; 8:e3065. [PMID: 34532529 DOI: 10.21769/bioprotoc.3065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/06/2018] [Accepted: 10/22/2018] [Indexed: 11/02/2022] Open
Abstract
Ralstonia solanacearum (F1C1) is a Gram-negative plant pathogenic bacterium that causes lethal wilt disease in a wide range of plant species. This pathogen is very well known for its unpredictable behavior during infection and wilting its host. Because of its mysterious infection behavior, virulence and pathogenicity standardization are still a big challenge in the case of R. solanacearum. Here, we report an innovative pathogenicity assay of R. solanacearum (F1C1) in the early stage of tomato seedlings by root dip inoculation. In this assay, we employed 6-7days old tomato seedlings for infection grown under nutrients free and gnotobiotic condition. After that, pathogenicity assay was performed by maintaining the inoculated seedlings in 1.5 or 2 ml sterile microfuge tubes. During infection, wilting symptom starts appearing from ~48 h post inoculation and the pathogenicity assay gets completed within seven days of post inoculation. This method is rapid, consistent as well as less resource dependent in terms of labor, space and cost to screen large numbers of plants. Hence, this newly developed assay is an easy and useful approach to study pathogen virulence functions and its interaction with the host plant during wilting and disease progression at the seedling stage.
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Affiliation(s)
- Niraj Singh
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Rahul Kumar
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India.,Plant Microbe Interactions Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Suvendra Kumar Ray
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
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Khokhani D, Tran TM, Lowe-Power TM, Allen C. Plant Assays for Quantifying Ralstonia solanacearum Virulence. Bio Protoc 2018; 8:e3028. [PMID: 34395814 DOI: 10.21769/bioprotoc.3028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 12/15/2022] Open
Abstract
Virulence assays are powerful tools to study microbial pathogenesis in vivo. Good assays track disease development and, coupled with targeted mutagenesis, can identify pathogen virulence factors. Disease development in plants is extremely sensitive to environmental factors such as temperature, atmospheric humidity, and soil water level, so it can be challenging to standardize conditions to achieve consistent results. Here, we present optimized and validated experimental conditions and analysis methods for nine assays that measure specific aspects of virulence in the phytopathogenic bacterium Ralstonia solanacearum, using tomato as the model host plant.
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Affiliation(s)
- Devanshi Khokhani
- Department of Bacteriology, University of Wisconsin-Madison, Madison, USA
| | - Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore
| | | | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, USA
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29
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Wu D, Schandry N, Lahaye T. A modular toolbox for Golden-Gate-based plasmid assembly streamlines the generation of Ralstonia solanacearum species complex knockout strains and multi-cassette complementation constructs. MOLECULAR PLANT PATHOLOGY 2018; 19:1511-1522. [PMID: 29077245 PMCID: PMC6638168 DOI: 10.1111/mpp.12632] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/02/2017] [Accepted: 10/22/2017] [Indexed: 05/15/2023]
Abstract
Members of the Ralstonia solanacearum species complex (Rssc) cause bacterial wilt, a devastating plant disease that affects numerous economically important crops. Like other bacterial pests, Rssc injects a cocktail of effector proteins via the bacterial type III secretion system into host cells that collectively promote disease. Given their functional relevance in disease, the identification of Rssc effectors and the investigation of their in planta function are likely to provide clues on how to generate pest-resistant crop plants. Accordingly, molecular analysis of effector function is a focus of Rssc research. The elucidation of effector function requires corresponding gene knockout strains or strains that express the desired effector variants. The cloning of DNA constructs that facilitate the generation of such strains has hindered the investigation of Rssc effectors. To overcome these limitations, we have designed, generated and functionally validated a toolkit consisting of DNA modules that can be assembled via Golden-Gate (GG) cloning into either desired gene knockout constructs or multi-cassette expression constructs. The Ralstonia-GG-kit is compatible with a previously established toolkit that facilitates the generation of DNA constructs for in planta expression. Accordingly, cloned modules, encoding effectors of interest, can be transferred to vectors for expression in Rssc strains and plant cells. As many effector genes have been cloned in the past as GATEWAY entry vectors, we have also established a conversion vector that allows the implementation of GATEWAY entry vectors into the Ralstonia-GG-kit. In summary, the Ralstonia-GG-kit provides a valuable tool for the genetic investigation of genes encoding effectors and other Rssc genes.
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Affiliation(s)
- Dousheng Wu
- Center for Plant Molecular Biology, Eberhard‐Karls‐University TübingenTübingen 72076Germany
| | - Niklas Schandry
- Center for Plant Molecular Biology, Eberhard‐Karls‐University TübingenTübingen 72076Germany
- Present address:
Gregor‐Mendel Institute of Molecular Plant Biology, Dr. Bohr Gasse 3Vienna 1030Austria
| | - Thomas Lahaye
- Center for Plant Molecular Biology, Eberhard‐Karls‐University TübingenTübingen 72076Germany
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Singh N, Phukan T, Sharma PL, Kabyashree K, Barman A, Kumar R, Sonti RV, Genin S, Ray SK. An Innovative Root Inoculation Method to Study Ralstonia solanacearum Pathogenicity in Tomato Seedlings. PHYTOPATHOLOGY 2018; 108:436-442. [PMID: 29182472 DOI: 10.1094/phyto-08-17-0291-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, we report Ralstonia solanacearum pathogenicity in the early stages of tomato seedlings by an innovative root inoculation method. Pathogenicity assays were performed under gnotobiotic conditions in microfuge tubes by employing only 6- to 7-day-old tomato seedlings for root inoculation. Tomato seedlings inoculated by this method exhibited the wilted symptom within 48 h and the virulence assay can be completed in 2 weeks. Colonization of the wilted seedlings by R. solanacearum was confirmed by using gus staining as well as fluorescence microscopy. Using this method, mutants in different virulence genes such as hrpB, phcA, and pilT could be clearly distinguished from wild-type R. solanacearum. The method described here is economic in terms of space, labor, and cost as well as the required quantity of bacterial inoculum. Thus, the newly developed assay is an easy and useful approach for investigating virulence functions of the pathogen at the seedling stage of hosts, and infection under these conditions appears to require pathogenicity mechanisms used by the pathogen for infection of adult plants.
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Affiliation(s)
- N Singh
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - T Phukan
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - P L Sharma
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - K Kabyashree
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - A Barman
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - R Kumar
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - R V Sonti
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - S Genin
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
| | - S K Ray
- First, second, third, fourth, fifth, sixth, and ninth authors: Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India; seventh author: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, Andhra Pradesh, India; and eighth author: LIPM, Université de Toulouse, INRA, CNRS, F-31326 Castanet-Tolosan, France
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Rufián JS, Macho AP, Corry DS, Mansfield JW, Ruiz‐Albert J, Arnold DL, Beuzón CR. Confocal microscopy reveals in planta dynamic interactions between pathogenic, avirulent and non-pathogenic Pseudomonas syringae strains. MOLECULAR PLANT PATHOLOGY 2018; 19:537-551. [PMID: 28120374 PMCID: PMC6638015 DOI: 10.1111/mpp.12539] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/12/2017] [Accepted: 01/17/2017] [Indexed: 05/04/2023]
Abstract
Recent advances in genomics and single-cell analysis have demonstrated the extraordinary complexity reached by microbial populations within their hosts. Communities range from complex multispecies groups to homogeneous populations differentiating into lineages through genetic or non-genetic mechanisms. Diversity within bacterial populations is recognized as a key driver of the evolution of animal pathogens. In plants, however, little is known about how interactions between different pathogenic and non-pathogenic variants within the host impact on defence responses, or how the presence within a mixture may affect the development or the fate of each variant. Using confocal fluorescence microscopy, we analysed the colonization of the plant apoplast by individual virulence variants of Pseudomonas syringae within mixed populations. We found that non-pathogenic variants can proliferate and even spread beyond the inoculated area to neighbouring tissues when in close proximity to pathogenic bacteria. The high bacterial concentrations reached at natural entry points promote such interactions during the infection process. We also found that a diversity of interactions take place at a cellular level between virulent and avirulent variants, ranging from dominant negative effects on proliferation of virulent bacteria to in trans suppression of defences triggered by avirulent bacteria. Our results illustrate the spatial dynamics and complexity of the interactions found within mixed infections, and their potential impact on pathogen evolution.
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Affiliation(s)
- José S. Rufián
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
| | - Alberto P. Macho
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
- Present address:
Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological SciencesChinese Academy of SciencesShanghai201602China
| | - David S. Corry
- Centre for Research in Bioscience, Faculty of Health and Applied SciencesUniversity of the West of England, Frenchay CampusBristolBS16 1QYUK
| | | | - Javier Ruiz‐Albert
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
| | - Dawn L. Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied SciencesUniversity of the West of England, Frenchay CampusBristolBS16 1QYUK
| | - Carmen R. Beuzón
- Instituto de Hortofruticultura Subtropical y Mediterranea “La Mayora”Universidad de Malaga‐Consejo Superior de Investigaciones Cientificas (IHSM‐UMA‐CSIC), Departamento Biologia Celular, Genetica y Fisiologia, Campus de Teatinos, Malaga E‐29071, Spain
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Complete genome sequence of the sesame pathogen Ralstonia solanacearum strain SEPPX 05. Genes Genomics 2018; 40:657-668. [PMID: 29892946 DOI: 10.1007/s13258-018-0667-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/04/2018] [Indexed: 10/18/2022]
Abstract
Ralstonia solanacearum is a soil-borne phytopathogen associated with bacterial wilt disease of sesame. R. solanacearum is the predominant agent causing damping-off from tropical to temperate regions. Because bacterial wilt has decreased the sesame industry yield, we sequenced the SEPPX05 genome using PacBio and Illumina HiSeq 2500 systems and revealed that R. solanacearum strain SEPPX05 carries a bipartite genome consisting of a 3,930,849 bp chromosome and a 2,066,085 bp megaplasmid with 66.84% G+C content that harbors 5,427 coding sequences. Based on the whole genome, phylogenetic analysis showed that strain SEPPX05 is grouped with two phylotype I strains (EP1 and GMI1000). Pan-genomic analysis shows that R. solanacearum is a complex species with high biological diversity and was able to colonize various environments during evolution. Despite deletions, insertions, and inversions, most genes of strain SEPPX05 have relatively high levels of synteny compared with strain GMI1000. We identified 104 genes involved in virulence-related factors in the SEPPX05 genome and eight absent genes encoding T3Es of GMI1000. Comparing SEPPX05 with other species, we found highly conserved secretion systems central to modulating interactions of host bacteria. These data may provide important clues for understanding underlying pathogenic mechanisms of R. solanacearum and help in the control of sesame bacterial wilt.
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Morel A, Peeters N, Vailleau F, Barberis P, Jiang G, Berthomé R, Guidot A. Plant Pathogenicity Phenotyping of Ralstonia solanacearum Strains. Methods Mol Biol 2018; 1734:223-239. [PMID: 29288458 DOI: 10.1007/978-1-4939-7604-1_18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this chapter, we describe different methods for phenotyping strains or mutants of the bacterial wilt agent, Ralstonia solanacearum, on four different host plants: Arabidopsis thaliana, tomato (Solanum lycopersicum), tobacco (Nicotiana benthamiana), or Medicago truncatula. Methods for preparation of high volume or low volume inocula are first described. Then, we describe the procedures for inoculation of plants by soil drenching, stem injection or leaf infiltration, and scoring of the wilting symptoms development. Two methods for measurement of bacterial multiplication in planta are also proposed: (1) counting the bacterial colonies upon serial dilution plating and (2) determining the bacterial concentration using a qPCR approach. In this chapter, we also describe a competitive index assay to compare the fitness of two strains coinoculated in the same plant. Lastly, specific protocols describe in vitro and hydroponic inoculation procedures to follow disease development and bacterial multiplication in both the roots and aerial parts of the plant.
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Affiliation(s)
- Arry Morel
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France
| | - Nemo Peeters
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France
| | - Fabienne Vailleau
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France
| | - Patrick Barberis
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France
| | - Gaofei Jiang
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France
| | - Richard Berthomé
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France
| | - Alice Guidot
- LIPM, Université de Toulouse, INRA, CNRS, INPT, Castanet-Tolosan, France.
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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. MOLECULAR PLANT PATHOLOGY 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] [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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35
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Capela D, Marchetti M, Clérissi C, Perrier A, Guetta D, Gris C, Valls M, Jauneau A, Cruveiller S, Rocha EPC, Masson-Boivin C. Recruitment of a Lineage-Specific Virulence Regulatory Pathway Promotes Intracellular Infection by a Plant Pathogen Experimentally Evolved into a Legume Symbiont. Mol Biol Evol 2017; 34:2503-2521. [PMID: 28535261 DOI: 10.1093/molbev/msx165] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ecological transitions between different lifestyles, such as pathogenicity, mutualism and saprophytism, have been very frequent in the course of microbial evolution, and often driven by horizontal gene transfer. Yet, how genomes achieve the ecological transition initiated by the transfer of complex biological traits remains poorly known. Here, we used experimental evolution, genomics, transcriptomics and high-resolution phenotyping to analyze the evolution of the plant pathogen Ralstonia solanacearum into legume symbionts, following the transfer of a natural plasmid encoding the essential mutualistic genes. We show that a regulatory pathway of the recipient R. solanacearum genome involved in extracellular infection of natural hosts was reused to improve intracellular symbiosis with the Mimosa pudica legume. Optimization of intracellular infection capacity was gained through mutations affecting two components of a new regulatory pathway, the transcriptional regulator efpR and a region upstream from the RSc0965-0967 genes of unknown functions. Adaptive mutations caused the downregulation of efpR and the over-expression of a downstream regulatory module, the three unknown genes RSc3146-3148, two of which encoding proteins likely associated to the membrane. This over-expression led to important metabolic and transcriptomic changes and a drastic qualitative and quantitative improvement of nodule intracellular infection. In addition, these adaptive mutations decreased the virulence of the original pathogen. The complete efpR/RSc3146-3148 pathway could only be identified in the genomes of the pathogenic R. solanacearum species complex. Our findings illustrate how the rewiring of a genetic network regulating virulence allows a radically different type of symbiotic interaction and contributes to ecological transitions and trade-offs.
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Affiliation(s)
- Delphine Capela
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Marta Marchetti
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Camille Clérissi
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.,Microbial Evolutionary Genomics, Institut Pasteur, Paris, France.,CNRS, UMR3525, Paris, France
| | - Anthony Perrier
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Dorian Guetta
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Carine Gris
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Marc Valls
- Department of Genetics, University of Barcelona and Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Edifici CRAG, Campus UAB, Bellaterra, Spain
| | - Alain Jauneau
- Fédération de Recherches Agrobiosciences, Interactions, Biodiversity, Plateforme d'Imagerie TRI, CNRS, UPS, Castanet-Tolosan, France
| | - Stéphane Cruveiller
- CNRS-UMR8030 and Commissariat à l'Energie Atomique et aux Energies Alternatives CEA/DRF/IG/GEN LABGeM, Evry, France
| | - Eduardo P C Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, Paris, France.,CNRS, UMR3525, Paris, France
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Segonzac C, Newman TE, Choi S, Jayaraman J, Choi DS, Jung GY, Cho H, Lee YK, Sohn KH. A Conserved EAR Motif Is Required for Avirulence and Stability of the Ralstonia solanacearum Effector PopP2 In Planta. FRONTIERS IN PLANT SCIENCE 2017; 8:1330. [PMID: 28824668 PMCID: PMC5539180 DOI: 10.3389/fpls.2017.01330] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/17/2017] [Indexed: 05/20/2023]
Abstract
Ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease in many high value Solanaceae crops. R. solanacearum secretes around 70 effectors into host cells in order to promote infection. Plants have, however, evolved specialized immune receptors that recognize corresponding effectors and confer qualitative disease resistance. In the model species Arabidopsis thaliana, the paired immune receptors RRS1 (resistance to Ralstonia solanacearum 1) and RPS4 (resistance to Pseudomonas syringae 4) cooperatively recognize the R. solanacearum effector PopP2 in the nuclei of infected cells. PopP2 is an acetyltransferase that binds to and acetylates the RRS1 WRKY DNA-binding domain resulting in reduced RRS1-DNA association thereby activating plant immunity. Here, we surveyed the naturally occurring variation in PopP2 sequence among the R. solanacearum strains isolated from diseased tomato and pepper fields across the Republic of Korea. Our analysis revealed high conservation of popP2 sequence with only three polymorphic alleles present amongst 17 strains. Only one variation (a premature stop codon) caused the loss of RPS4/RRS1-dependent recognition in Arabidopsis. We also found that PopP2 harbors a putative eukaryotic transcriptional repressor motif (ethylene-responsive element binding factor-associated amphiphilic repression or EAR), which is known to be involved in the recruitment of transcriptional co-repressors. Remarkably, mutation of the EAR motif disabled PopP2 avirulence function as measured by the development of hypersensitive response, electrolyte leakage, defense marker gene expression and bacterial growth in Arabidopsis. This lack of recognition was partially but significantly reverted by the C-terminal addition of a synthetic EAR motif. We show that the EAR motif-dependent gain of avirulence correlated with the stability of the PopP2 protein. Furthermore, we demonstrated the requirement of the PopP2 EAR motif for PTI suppression. A yeast two-hybrid screen indicated that PopP2 does not interact with any well-known Arabidopsis transcriptional co-repressors. Overall, this study reveals high conservation of the PopP2 effector in Korean R. solanacearum strains isolated from commercially cultivated tomato and pepper genotypes. Importantly, our data also indicate that the PopP2 conserved repressor motif could contribute to the effector accumulation in plant cells.
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Affiliation(s)
- Cécile Segonzac
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
- Plant Science Department, Plant Genomics and Breeding Institute and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National UniversitySeoul, South Korea
- *Correspondence: Kee Hoon Sohn, Cécile Segonzac,
| | - Toby E. Newman
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
- Bioprotection Centre of Research Excellence, Institute of Agriculture and Environment, Massey UniversityPalmerston North, New Zealand
| | - Sera Choi
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
- Bioprotection Centre of Research Excellence, Institute of Agriculture and Environment, Massey UniversityPalmerston North, New Zealand
| | - Jay Jayaraman
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
- Bioprotection Centre of Research Excellence, Institute of Agriculture and Environment, Massey UniversityPalmerston North, New Zealand
| | - Du Seok Choi
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
| | - Ga Young Jung
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
| | - Heejung Cho
- National Institute of Agricultural Sciences, Rural Development AdministrationWanju, South Korea
| | - Young Kee Lee
- National Institute of Agricultural Sciences, Rural Development AdministrationWanju, South Korea
| | - Kee Hoon Sohn
- Department of Life Sciences, Pohang University of Science and TechnologyPohang, South Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and TechnologyPohang, South Korea
- *Correspondence: Kee Hoon Sohn, Cécile Segonzac,
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37
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Fitness costs restrict niche expansion by generalist niche-constructing pathogens. ISME JOURNAL 2016; 11:374-385. [PMID: 27801902 DOI: 10.1038/ismej.2016.137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/04/2016] [Accepted: 09/07/2016] [Indexed: 01/13/2023]
Abstract
We investigated the molecular and ecological mechanisms involved in niche expansion, or generalism, versus specialization in sympatric plant pathogens. Nopaline-type and octopine-type Agrobacterium tumefaciens engineer distinct niches in their plant hosts that provide different nutrients: nopaline or octopine, respectively. Previous studies revealed that nopaline-type pathogens may expand their niche to also assimilate octopine in the presence of nopaline, but consequences of this phenomenon on pathogen dynamics in planta were not known. Here, we provided molecular insight into how the transport protein NocT can bind octopine as well as nopaline, contributing to niche expansion. We further showed that despite the ability for niche expansion, nopaline-type pathogens had no competitive advantage over octopine-type pathogens in co-infected plants. We also demonstrated that a single nucleotide polymorphism in the nocR gene was sufficient to allow octopine assimilation by nopaline-type strains even in absence of nopaline. The evolved nocR bacteria had higher fitness than their ancestor in octopine-rich transgenic plants but lower fitness in tumors induced by octopine-type pathogens. Overall, this work elucidates the specialization of A. tumefaciens to particular opine niches and explains why generalists do not always spread despite the advantage associated with broader nutritional niches.
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38
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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: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [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] [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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Macho AP, Rufián JS, Ruiz-Albert J, Beuzón CR. Competitive Index: Mixed Infection-Based Virulence Assays for Genetic Analysis in Pseudomonas syringae-Plant Interactions. Methods Mol Biol 2016; 1363:209-217. [PMID: 26577792 DOI: 10.1007/978-1-4939-3115-6_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
When studying bacterial plant pathogens, the genetic analysis of the contribution of virulence factors to the infection process has traditionally been hindered by their high degree of functional redundancy. In recent years, it has become clear that the use of competitive index in mixed infections provides an accurate and sensitive manner of establishing virulence phenotypes for mutants for which other assays have failed. Such increases in sensitivity and accuracy are due to the direct comparison between the respective growths of the co-inoculated strains within the same infection, each strain replicating as they would in individual infections. Interferences between the co-inoculated strains must be therefore avoided using the appropriate experimental settings. In this chapter, we will present the optimal experimental conditions to achieve maximum sensitivity on virulence assays using the phytopathogenic bacterium Pseudomonas syringae, as well as some additional considerations to ensure the correct interpretations of the results.
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Affiliation(s)
- Alberto P Macho
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - José S Rufián
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Campus de Teatinos, Avda. Cervantes 2, Málaga, E-29071, Spain
| | - Javier Ruiz-Albert
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Campus de Teatinos, Avda. Cervantes 2, Málaga, E-29071, Spain
| | - Carmen R Beuzón
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Campus de Teatinos, Avda. Cervantes 2, Málaga, E-29071, Spain.
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Schandry N, de Lange O, Prior P, Lahaye T. TALE-Like Effectors Are an Ancestral Feature of the Ralstonia solanacearum Species Complex and Converge in DNA Targeting Specificity. FRONTIERS IN PLANT SCIENCE 2016; 7:1225. [PMID: 27582755 PMCID: PMC4987410 DOI: 10.3389/fpls.2016.01225] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/02/2016] [Indexed: 05/19/2023]
Abstract
Ralstonia solanacearum, a species complex of bacterial plant pathogens divided into four monophyletic phylotypes, causes plant diseases in tropical climates around the world. Some strains exhibit a broad host range on solanaceous hosts, while others are highly host-specific as for example some banana-pathogenic strains. Previous studies showed that transcription activator-like (TAL) effectors from Ralstonia, termed RipTALs, are capable of activating reporter genes in planta, if these are preceded by a matching effector binding element (EBE). RipTALs target DNA via their central repeat domain (CRD), where one repeat pairs with one DNA-base of the given EBE. The repeat variable diresidue dictates base repeat specificity in a predictable fashion, known as the TALE code. In this work, we analyze RipTALs across all phylotypes of the Ralstonia solanacearum species complex. We find that RipTALs are prevalent in phylotypes I and IV but absent from most phylotype III and II strains (10/12, 8/14, 1/24, and 1/5 strains contained a RipTAL, respectively). RipTALs originating from strains of the same phylotype show high levels of sequence similarity (>98%) in the N-terminal and C-terminal regions, while RipTALs isolated from different phylotypes show 47-91% sequence similarity in those regions, giving rise to four RipTAL classes. We show that, despite sequence divergence, the base preference for guanine, mediated by the N-terminal region, is conserved across RipTALs of all classes. Using the number and order of repeats found in the CRD, we functionally sub-classify RipTALs, introduce a new simple nomenclature, and predict matching EBEs for all seven distinct RipTALs identified. We experimentally study RipTAL EBEs and uncover that some RipTALs are able to target the EBEs of other RipTALs, referred to as cross-reactivity. In particular, RipTALs from strains with a broad host range on solanaceous hosts cross-react on each other's EBEs. Investigation of sequence divergence between RipTAL repeats allows for a reconstruction of repeat array biogenesis, for example through slipped strand mispairing or gene conversion. Using these studies we show how RipTALs of broad host range strains evolved convergently toward a shared target sequence. Finally, we discuss the differences between TALE-likes of plant pathogens in the context of disease ecology.
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Affiliation(s)
- Niklas Schandry
- Center for Plant Molecular Biology, University of TübingenTübingen, Germany
| | - Orlando de Lange
- Center for Plant Molecular Biology, University of TübingenTübingen, Germany
| | - Philippe Prior
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Centre de Coopération Internationale en Recherche Agronomique pour le Développement – Institut National de la Recherche AgronomiqueSaint-Pierre, France
| | - Thomas Lahaye
- Center for Plant Molecular Biology, University of TübingenTübingen, Germany
- *Correspondence: Thomas Lahaye,
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Pensec F, Lebeau A, Daunay MC, Chiroleu F, Guidot A, Wicker E. Towards the Identification of Type III Effectors Associated with Ralstonia solanacearum Virulence on Tomato and Eggplant. PHYTOPATHOLOGY 2015; 105:1529-44. [PMID: 26368514 DOI: 10.1094/phyto-06-15-0140-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
For the development of pathogen-informed breeding strategies, identifying the microbial genes involved in interactions with the plant is a critical step. To identify type III effector (T3E) repertoires associated with virulence of the bacterial wilt pathogen Ralstonia solanacearum on Solanaceous crops, we used an original association genetics approach combining DNA microarray data and pathogenicity data on resistant eggplant, pepper, and tomato accessions. From this first screen, 25 T3Es were further full-length polymerase chain reaction-amplified within a 35-strain field collection, to assess their distribution and allelic diversity. Six T3E repertoire groups were identified, within which 11 representative strains were chosen to challenge the bacterial wilt-resistant egg plants 'Dingras multiple Purple' and 'AG91-25', and tomato Hawaii 7996. The virulence or avirulence phenotypes could not be explained by specific T3E repertoires, but rather by individual T3E genes. We identified seven highly avirulence-associated genes, among which ripP2, primarily referenced as conferring avirulence to Arabidopsis thaliana. Interestingly, no T3E was associated with avirulence to both egg-plants. Highly virulence-associated genes were also identified: ripA5_2, ripU, and ripV2. This study should be regarded as a first step toward investigating both avirulence and virulence function of the highlighted genes, but also their evolutionary dynamics in natural R. solanacearum populations.
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Affiliation(s)
- Flora Pensec
- First, second, fourth, and sixth authors: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint-Pierre, La Réunion, France; third author: INRA, Centre d'Avignon, Unité de Génétique et Amélioration des Fruits et Légumes, UR1052, Montfavet, France; and fifth author: INRA, UMR 441 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Castanet-Tolosan, France. Current address of first author: Institut National de la Recherche Agronomique, UMR A 1131 Santé de la Vigne et Qualité du Vin (SVQV), Colmar, France. Université de Strasbourg, Strasbourg, France
| | - Aurore Lebeau
- First, second, fourth, and sixth authors: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint-Pierre, La Réunion, France; third author: INRA, Centre d'Avignon, Unité de Génétique et Amélioration des Fruits et Légumes, UR1052, Montfavet, France; and fifth author: INRA, UMR 441 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Castanet-Tolosan, France. Current address of first author: Institut National de la Recherche Agronomique, UMR A 1131 Santé de la Vigne et Qualité du Vin (SVQV), Colmar, France. Université de Strasbourg, Strasbourg, France
| | - M C Daunay
- First, second, fourth, and sixth authors: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint-Pierre, La Réunion, France; third author: INRA, Centre d'Avignon, Unité de Génétique et Amélioration des Fruits et Légumes, UR1052, Montfavet, France; and fifth author: INRA, UMR 441 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Castanet-Tolosan, France. Current address of first author: Institut National de la Recherche Agronomique, UMR A 1131 Santé de la Vigne et Qualité du Vin (SVQV), Colmar, France. Université de Strasbourg, Strasbourg, France
| | - Frédéric Chiroleu
- First, second, fourth, and sixth authors: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint-Pierre, La Réunion, France; third author: INRA, Centre d'Avignon, Unité de Génétique et Amélioration des Fruits et Légumes, UR1052, Montfavet, France; and fifth author: INRA, UMR 441 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Castanet-Tolosan, France. Current address of first author: Institut National de la Recherche Agronomique, UMR A 1131 Santé de la Vigne et Qualité du Vin (SVQV), Colmar, France. Université de Strasbourg, Strasbourg, France
| | - Alice Guidot
- First, second, fourth, and sixth authors: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint-Pierre, La Réunion, France; third author: INRA, Centre d'Avignon, Unité de Génétique et Amélioration des Fruits et Légumes, UR1052, Montfavet, France; and fifth author: INRA, UMR 441 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Castanet-Tolosan, France. Current address of first author: Institut National de la Recherche Agronomique, UMR A 1131 Santé de la Vigne et Qualité du Vin (SVQV), Colmar, France. Université de Strasbourg, Strasbourg, France
| | - Emmanuel Wicker
- First, second, fourth, and sixth authors: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint-Pierre, La Réunion, France; third author: INRA, Centre d'Avignon, Unité de Génétique et Amélioration des Fruits et Légumes, UR1052, Montfavet, France; and fifth author: INRA, UMR 441 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Castanet-Tolosan, France. Current address of first author: Institut National de la Recherche Agronomique, UMR A 1131 Santé de la Vigne et Qualité du Vin (SVQV), Colmar, France. Université de Strasbourg, Strasbourg, France
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Lowe TM, Ailloud F, Allen C. Hydroxycinnamic Acid Degradation, a Broadly Conserved Trait, Protects Ralstonia solanacearum from Chemical Plant Defenses and Contributes to Root Colonization and Virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:286-97. [PMID: 25423265 PMCID: PMC4329107 DOI: 10.1094/mpmi-09-14-0292-fi] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Plants produce hydroxycinnamic acid (HCA) defense compounds to combat pathogens, such as the bacterium Ralstonia solanacearum. We showed that an HCA degradation pathway is genetically and functionally conserved across diverse R. solanacearum strains. Further, a feruloyl-CoA synthetase (Δfcs) mutant that cannot degrade HCA was less virulent on tomato plants. To understand the role of HCA degradation in bacterial wilt disease, we tested the following hypotheses: HCA degradation helps the pathogen i) grow, as a carbon source; ii) spread, by reducing HCA-derived physical barriers; and iii) survive plant antimicrobial compounds. Although HCA degradation enabled R. solanacearum growth on HCA in vitro, HCA degradation was dispensable for growth in xylem sap and root exudate, suggesting that HCA are not significant carbon sources in planta. Acetyl-bromide quantification of lignin demonstrated that R. solanacearum infections did not affect the gross quantity or distribution of stem lignin. However, the Δfcs mutant was significantly more susceptible to inhibition by two HCA, namely, caffeate and p-coumarate. Finally, plant colonization assays suggested that HCA degradation facilitates early stages of infection and root colonization. Together, these results indicated that ability to degrade HCA contributes to bacterial wilt virulence by facilitating root entry and by protecting the pathogen from HCA toxicity.
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Affiliation(s)
- Tiffany M. Lowe
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Florent Ailloud
- Peuplements Végétaux et Bioagresseurs en Milieu Tropical (UMR PVBMT), INRA-CIRAD, Saint Pierre, La Réunion, France
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
- Corresponding Author: Caitilyn Allen; ; 608-262-9578
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Mesarich CH, Bowen JK, Hamiaux C, Templeton MD. Repeat-containing protein effectors of plant-associated organisms. FRONTIERS IN PLANT SCIENCE 2015; 6:872. [PMID: 26557126 PMCID: PMC4617103 DOI: 10.3389/fpls.2015.00872] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/01/2015] [Indexed: 05/10/2023]
Abstract
Many plant-associated organisms, including microbes, nematodes, and insects, deliver effector proteins into the apoplast, vascular tissue, or cell cytoplasm of their prospective hosts. These effectors function to promote colonization, typically by altering host physiology or by modulating host immune responses. The same effectors however, can also trigger host immunity in the presence of cognate host immune receptor proteins, and thus prevent colonization. To circumvent effector-triggered immunity, or to further enhance host colonization, plant-associated organisms often rely on adaptive effector evolution. In recent years, it has become increasingly apparent that several effectors of plant-associated organisms are repeat-containing proteins (RCPs) that carry tandem or non-tandem arrays of an amino acid sequence or structural motif. In this review, we highlight the diverse roles that these repeat domains play in RCP effector function. We also draw attention to the potential role of these repeat domains in adaptive evolution with regards to RCP effector function and the evasion of effector-triggered immunity. The aim of this review is to increase the profile of RCP effectors from plant-associated organisms.
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Affiliation(s)
- Carl H. Mesarich
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
- *Correspondence: Carl H. Mesarich
| | - Joanna K. Bowen
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
| | - Cyril Hamiaux
- Human Responses, The New Zealand Institute for Plant & Food Research LimitedAuckland, New Zealand
| | - Matthew D. Templeton
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
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A Ralstonia solanacearum type III effector directs the production of the plant signal metabolite trehalose-6-phosphate. mBio 2014; 5:mBio.02065-14. [PMID: 25538193 PMCID: PMC4278537 DOI: 10.1128/mbio.02065-14] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The plant pathogen Ralstonia solanacearum possesses two genes encoding a trehalose-6-phosphate synthase (TPS), an enzyme of the trehalose biosynthetic pathway. One of these genes, named ripTPS, was found to encode a protein with an additional N-terminal domain which directs its translocation into host plant cells through the type 3 secretion system. RipTPS is a conserved effector in the R. solanacearum species complex, and homologues were also detected in other bacterial plant pathogens. Functional analysis of RipTPS demonstrated that this type 3 effector synthesizes trehalose-6-phosphate and identified residues essential for this enzymatic activity. Although trehalose-6-phosphate is a key signal molecule in plants that regulates sugar status and carbon assimilation, the disruption of ripTPS did not alter the virulence of R. solanacearum on plants. However, heterologous expression assays showed that this effector specifically elicits a hypersensitive-like response on tobacco that is independent of its enzymatic activity and is triggered by the C-terminal half of the protein. Recognition of this effector by the plant immune system is suggestive of a role during the infectious process. Ralstonia solanacearum, the causal agent of bacterial wilt disease, infects more than two hundred plant species, including economically important crops. The type III secretion system plays a major role in the pathogenicity of this bacterium, and approximately 70 effector proteins have been shown to be translocated into host plant cells. This study provides the first description of a type III effector endowed with a trehalose-6-phosphate synthase enzymatic activity and illustrates a new mechanism by which the bacteria may manipulate the plant metabolism upon infection. In recent years, trehalose-6-phosphate has emerged as an essential signal molecule in plants, connecting plant metabolism and development. The finding that a bacterial pathogen could induce the production of trehalose-6-phosphate in plant cells further highlights the importance of this metabolite in multiple aspects of the molecular physiology of plants.
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Agrobacterium uses a unique ligand-binding mode for trapping opines and acquiring a competitive advantage in the niche construction on plant host. PLoS Pathog 2014; 10:e1004444. [PMID: 25299655 PMCID: PMC4192606 DOI: 10.1371/journal.ppat.1004444] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 09/02/2014] [Indexed: 11/20/2022] Open
Abstract
By modifying the nuclear genome of its host, the plant pathogen Agrobacterium tumefaciens induces the development of plant tumours in which it proliferates. The transformed plant tissues accumulate uncommon low molecular weight compounds called opines that are growth substrates for A. tumefaciens. In the pathogen-induced niche (the plant tumour), a selective advantage conferred by opine assimilation has been hypothesized, but not experimentally demonstrated. Here, using genetics and structural biology, we deciphered how the pathogen is able to bind opines and use them to efficiently compete in the plant tumour. We report high resolution X-ray structures of the periplasmic binding protein (PBP) NocT unliganded and liganded with the opine nopaline (a condensation product of arginine and α-ketoglurate) and its lactam derivative pyronopaline. NocT exhibited an affinity for pyronopaline (KD of 0.6 µM) greater than that for nopaline (KD of 3.7 µM). Although the binding-mode of the arginine part of nopaline/pyronopaline in NocT resembled that of arginine in other PBPs, affinity measurement by two different techniques showed that NocT did not bind arginine. In contrast, NocT presented specific residues such as M117 to stabilize the bound opines. NocT relatives that exhibit the nopaline/pyronopaline-binding mode were only found in genomes of the genus Agrobacterium. Transcriptomics and reverse genetics revealed that A. tumefaciens uses the same pathway for assimilating nopaline and pyronopaline. Fitness measurements showed that NocT is required for a competitive colonization of the plant tumour by A. tumefaciens. Moreover, even though the Ti-plasmid conjugal transfer was not regulated by nopaline, the competitive advantage gained by the nopaline-assimilating Ti-plasmid donors led to a preferential horizontal propagation of this Ti-plasmid amongst the agrobacteria colonizing the plant-tumour niche. This work provided structural and genetic evidences to support the niche construction paradigm in bacterial pathogens. An ecological niche is defined, in a given environment, by the availability of nutritive resources, which can be specifically assimilated by certain living organisms to promote their proliferation. The bacterial pathogen Agrobacterium tumefaciens is able to engineer an ecological niche in the infected host via the transformation of the plant genome and diversion of the plant metabolism towards production of the opine nutrients. In this work, we quantified the selective advantage conferred to a member of the phytopathogenic species A. tumefaciens which is able to assimilate the opine nopaline. This opine is a condensate of arginine and α-ketoglurate that is produced both under linear and cyclic forms in the plant tumour environment. We further determined at the molecular and atomistic levels how A. tumefaciens is able to sense the nopaline molecules, and which metabolic pathways are activated in response. Overall, this work deciphered some key molecular events in the niche construction of the pathogen A. tumefaciens that is unique among living organisms and used to develop bioengineering tools.
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Deslandes L, Genin S. Opening the Ralstonia solanacearum type III effector tool box: insights into host cell subversion mechanisms. CURRENT OPINION IN PLANT BIOLOGY 2014; 20:110-7. [PMID: 24880553 DOI: 10.1016/j.pbi.2014.05.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/23/2014] [Accepted: 05/01/2014] [Indexed: 05/19/2023]
Abstract
Effectors delivered to host cells by the Type III secretion system are essential to Ralstonia solanacearum pathogenicity, as in several other plant pathogenic bacteria. The establishment of exhaustive effector repertoires in multiple R. solanacearum strains drew a first picture of the evolutionary dynamics of the pathogen effector suites. Effector repertoires are diversified, with a core of 20-30 effectors present in most of the strains and the obtention of mutants lacking one or more effector genes revealed the functional overlap among this effector network. Recent functional studies have provided insights into the ability of single effectors to manipulate the host proteasome, elicit cell death, trigger the expression of plant genes, and/or display biochemical activities on plant protein targets.
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Affiliation(s)
- Laurent Deslandes
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan F-31326, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan F-31326, France
| | - Stephane Genin
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan F-31326, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan F-31326, France.
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48
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Guidot A, Jiang W, Ferdy JB, Thébaud C, Barberis P, Gouzy J, Genin S. Multihost experimental evolution of the pathogen Ralstonia solanacearum unveils genes involved in adaptation to plants. Mol Biol Evol 2014; 31:2913-28. [PMID: 25086002 DOI: 10.1093/molbev/msu229] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ralstonia solanacearum, the causal agent of a lethal bacterial wilt plant disease, infects an unusually wide range of hosts. These hosts can further be split into plants where R. solanacearum is known to cause disease (original hosts) and those where this bacterium can grow asymptomatically (distant hosts). Moreover, this pathogen is able to adapt to many plants as supported by field observations reporting emergence of strains with enlarged pathogenic properties. To investigate the genetic bases of host adaptation, we conducted evolution experiments by serial passages of a single clone of the pathogen on three original and two distant hosts over 300 bacterial generations and then analyzed the whole-genome of nine evolved clones. Phenotypic analysis of the evolved clones showed that the pathogen can increase its fitness on both original and distant hosts although the magnitude of fitness increase was greater on distant hosts. Only few genomic modifications were detected in evolved clones compared with the ancestor but parallel evolutionary changes in two genes were observed in independent evolved populations. Independent mutations in the regulatory gene efpR were selected for in three populations evolved on beans, a distant host. Reverse genetic approaches confirmed that these mutations were associated with fitness gain on bean plants. This work provides a first step toward understanding the within-host evolutionary dynamics of R. solanacearum during infection and identifying bacterial genes subjected to in planta selection. The discovery of EfpR as a determinant conditioning host adaptation of the pathogen illustrates how experimental evolution coupled with whole-genome sequencing is a potent tool to identify novel molecular players involved in central life-history traits.
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Affiliation(s)
- Alice Guidot
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
| | - Wei Jiang
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
| | - Jean-Baptiste Ferdy
- UPS-CNRS-ENFA, Laboratoire Évolution et Diversité Biologique (EDB), UMR5174, Université Paul Sabatier, Toulouse, France
| | - Christophe Thébaud
- UPS-CNRS-ENFA, Laboratoire Évolution et Diversité Biologique (EDB), UMR5174, Université Paul Sabatier, Toulouse, France
| | - Patrick Barberis
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
| | - Jérôme Gouzy
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
| | - Stéphane Genin
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
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Nahar K, Matsumoto I, Taguchi F, Inagaki Y, Yamamoto M, Toyoda K, Shiraishi T, Ichinose Y, Mukaihara T. Ralstonia solanacearum type III secretion system effector Rip36 induces a hypersensitive response in the nonhost wild eggplant Solanum torvum. MOLECULAR PLANT PATHOLOGY 2014; 15:297-303. [PMID: 24745046 PMCID: PMC6638889 DOI: 10.1111/mpp.12079] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Ralstonia solanacearum is a Gram-negative soil-borne bacterium that causes bacterial wilt disease in more than 200 plant species, including economically important Solanaceae species. In R. solanacearum, the hypersensitive response and pathogenicity (Hrp) type III secretion system is required for both the ability to induce the hypersensitive response (HR) in nonhost plants and pathogenicity in host plants. Recently, 72 effector genes, called rip (Ralstonia protein injected into plant cells), have been identified in R. solanacearum RS1000. RS1002, a spontaneous nalixidic acid-resistant derivative of RS1000, induced strong HR in the nonhost wild eggplant Solanum torvum in an Hrp-dependent manner. An Agrobacterium-mediated transient expression system revealed that Rip36, a putative Zn-dependent protease effector of R. solanacearum, induced HR in S. torvum. A mutation in the putative Zn-binding motif (E149A) completely abolished the ability to induce HR. In agreement with this result, the RS1002-derived Δrip36 and rip36E149A mutants lost the ability to induce HR in S. torvum. An E149A mutation had no effect on the translocation of Rip36 into plant cells. These results indicate that Rip36 is an avirulent factor that induces HR in S. torvum and that a putative Zn-dependent protease motif is essential for this activity.
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Hong JK, Kang SR, Kim YH, Yoon DJ, Kim DH, Kim HJ, Sung CH, Kang HS, Choi CW, Kim SH, Kim YS. Hydrogen Peroxide- and Nitric Oxide-mediated Disease Control of Bacterial Wilt in Tomato Plants. THE PLANT PATHOLOGY JOURNAL 2013; 29:386-96. [PMID: 25288967 PMCID: PMC4174819 DOI: 10.5423/ppj.oa.04.2013.0043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 08/21/2013] [Accepted: 08/23/2013] [Indexed: 05/10/2023]
Abstract
Reactive oxygen species (ROS) generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide (H2O2) and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion (O2 (-)) and H2O2 was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of H2O2and sodium nitroprusside (SNP) nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both H2O2and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by 10(6) and 10(7) cfu/ml of R. solanacearum. H2O2- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative 'area under the disease progressive curve (AUDPC)' was calculated to compare disease protection by H2O2 and/or SNP with untreated control. Neither H2O2 nor SNP protect the tomato seedlings from the bacterial wilt, but H2O2+ SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that H2O2 and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.
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Affiliation(s)
- Jeum Kyu Hong
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Su Ran Kang
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Yeon Hwa Kim
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Dong June Yoon
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Do Hoon Kim
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Hyeon Ji Kim
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Chang Hyun Sung
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Han Sol Kang
- Department of Horticultural Science, Gyeongnam National University of Science and Technology (GNTech), Jinju 660-758, Korea
| | - Chang Won Choi
- Department of Biology and Medical Science, Paichai University, Daejeon 302-735, Korea
| | - Seong Hwan Kim
- Department of Microbiology and Institute of Basic Sciences, Dankook University, Cheonan 330-714, Korea
| | - Young Shik Kim
- Department of Plant Science and Food Biotechnology, Sangmyung University, Cheonan 330-720, Korea
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