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Ding S, Ma Z, Yu L, Lan G, Tang Y, Li Z, He Z, She X. Comparative genomics and host range analysis of four Ralstonia pseudosolanacearum strains isolated from sunflower reveals genomic and phenotypic differences. BMC Genomics 2024; 25:191. [PMID: 38373891 PMCID: PMC10875864 DOI: 10.1186/s12864-024-10087-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 02/02/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Bacterial wilt caused by Ralstonia solanacearum species complex (RSSC) is one of the devastating diseases in crop production, seriously reducing the yield of crops. R. pseudosolanacearum, is known for its broad infrasubspecific diversity and comprises 36 sequevars that are currently known. Previous studies found that R. pseudosolanacearum contained four sequevars (13, 14, 17 and 54) isolated from sunflowers sown in the same field. RESULTS Here, we provided the complete genomes and the results of genome comparison of the four sequevars strains (RS639, RS642, RS647, and RS650). Four strains showed different pathogenicities to the same cultivars and different host ranges. Their genome sizes were about 5.84 ~ 5.94 Mb, encoding 5002 ~ 5079 genes and the average G + C content of 66.85% ~ 67%. Among the coding genes, 146 ~ 159 specific gene families (contained 150 ~ 160 genes) were found in the chromosomes and 34 ~ 77 specific gene families (contained 34 ~ 78 genes) in the megaplasmids from four strains. The average nucleotide identify (ANI) values between any two strains ranged from 99.05% ~ 99.71%, and the proportion of the total base length of collinear blocks accounts for the total gene length of corresponding genome was all more than 93.82%. Then, we performed a search for genomic islands, prophage sequences, the gene clusters macromolecular secretion systems, type III secreted effectors and other virulence factors in these strains, which provided detailed comparison results of their presence and distinctive features compared to the reference strain GMI1000. Among them, the number and types of T2SS gene clusters were different in the four strains, among which RS650 included all five types. T4SS gene cluster of RS639 and RS647 were missed. In the T6SS gene cluster, several genes were inserted in the RS639, RS647, and RS650, and gene deletion was also detected in the RS642. A total of 78 kinds of type III secreted effectors were found, which included 52 core and 9 specific effectors in four strains. CONCLUSION This study not only provided the complete genomes of multiple R. pseudosolanacearum strains isolated from a new host, but also revealed the differences in their genomic levels through comparative genomics. Furthermore, these findings expand human knowledge about the range of hosts that Ralstonia can infect, and potentially contribute to exploring rules and factors of the genetic evolution and analyzing its pathogenic mechanism.
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Affiliation(s)
- Shanwen Ding
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Zijun Ma
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Lin Yu
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Guobing Lan
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Yafei Tang
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Zhenggang Li
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Zifu He
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China.
| | - Xiaoman She
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China.
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Miao Y, Wu L, Xue Q, Zhang Q, Zou H. Ralstonia solanacearum type III effector RipAA targets chloroplastic AtpB to modulate an incompatible interaction on Nicotiana benthamiana. Front Microbiol 2023; 14:1179824. [PMID: 37275133 PMCID: PMC10232776 DOI: 10.3389/fmicb.2023.1179824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 03/30/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction The type III effector RipAA of Ralstonia solanacearum GMI1000 plays a critical role in the incompatible interaction on Nicotiana benthamiana. Methods The RipAA was transiently expressed in N. benthamiana by Agrobacterium-mediated transformation. Chemical staining with trypan blue and DAB were conducted to examine the cell death and the accumulation of hydrogen peroxide (H2O2), respectively. The expression of the marker genes for salicylic acid (SA) and jasmonic acid (JA) signaling was evaluated by quantitative reverse transcription PCR (qRT-PCR). The proteins interacted with RipAA was identified from N. benthamiana by yeast two-hybrid and pull-down assays. A TRV-mediated gene silencing was used to assess the role of host gene in response to RipAA expression and R. solanacearum infection. Results and discussion RipAA induced the accumulation of hydrogen peroxide (H2O2) and genome DNA degradation in N. benthamiana, which were accompanied by a hypersensitive reaction. Simultaneously, the marker genes for salicylic acid (SA) signaling were induced and those for jasmonic acid (JA) signaling were reduced. N. benthamiana chloroplastic AtpB, the ATPase β subunit, was identified as an interactor with RipAA. The silencing of atpB in N. benthamiana resulted in the inability of RipAA to induce a hypersensitive response, a compatible interaction with GMI1000, and an enhanced sensitivity to bacterial wilt. Our data support the concept that RipAA determines host-range specificity by targeting the host chloroplastic AtpB.
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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: 3] [Impact Index Per Article: 1.5] [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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Zhao M, Ge Y, Xu Z, Ouyang X, Jia Y, Liu J, Zhang M, An Y. A BTB/POZ domain-containing protein negatively regulates plant immunity in Nicotiana benthamiana. Biochem Biophys Res Commun 2022; 600:54-59. [PMID: 35189497 DOI: 10.1016/j.bbrc.2022.02.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 02/14/2022] [Indexed: 01/17/2023]
Abstract
Plants have evolved immune systems to fight against pathogens. However, it is still largely unknown how the plant immunity is finely regulated. Here we identified a BTB/POZ domain-containing protein, namely NbBTB, which is predicted to be a member of the ubiquitin E3 ligase complex. The NbBTB expression is downregulated upon the oomycete pathogen Phytophthora parasitica infection. Overexpression of NbBTB in Nicotiana benthamiana promoted plant susceptibility to P. parasitica infection, and silencing NbBTB increased plant resistance to P. parasitica, indicating that NbBTB negatively modulates plant basal defense. Interestingly, overexpressing or silencing NbBTB did not affect plant resistance to two bacterial pathogens Ralstonia solanacearum and Pseudomonas syringae, suggesting that NbBTB is specifically involved in basal defense against oomycete pathogen. Expression of NbBTB suppressed hypersensitive response (HR) triggered by avirulence proteins from both R. sonanacearum and P. infestans, and silencing NbBTB showed the opposite effect, indicating that NbBTB negatively regulates effector-triggered immunity (ETI). Protein accumulation of avirulence effectors in NbBTB-silenced plants was significantly enhanced, suggesting that NbBTB is likely to negatively modulate ETI by affecting effector protein accumulation. Together, our results demonstrated that NbBTB is a negative regulator in both plant basal defense and ETI.
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Affiliation(s)
- Mengwei Zhao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yu Ge
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhangyan Xu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xue Ouyang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuling Jia
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiangtao Liu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Meixiang Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Yuyan An
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, China.
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Du H, Yang J, Chen B, Zhang X, Xu X, Wen C, Geng S. Dual RNA-seq Reveals the Global Transcriptome Dynamics of Ralstonia solanacearum and Pepper ( Capsicum annuum) Hypocotyls During Bacterial Wilt Pathogenesis. PHYTOPATHOLOGY 2022; 112:630-642. [PMID: 34346759 DOI: 10.1094/phyto-01-21-0032-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bacterial wilt, caused by Ralstonia solanacearum, is a serious disease in pepper. However, the interaction between the pathogen and pepper remains largely unknown. This study aimed to gain insights into determinants of pepper susceptibility and R. solanacearum pathogenesis. We assembled the complete genome of R. solanacearum strain Rs-SY1 and identified 5,106 predicted genes, including 84 type III effectors (T3E). RNA-seq was used to identify differentially expressed genes (DEGs) in susceptible pepper CM334 at 1 and 5 days postinoculation (dpi) with R. solanacearum. Dual RNA-seq was used to simultaneously capture transcriptome changes in the host and pathogen at 3 and 7 dpi. A total of 1,400, 3,335, 2,878, and 4,484 DEGs of pepper (PDEGs) were identified in the CM334 hypocotyls at 1, 3, 5, and 7 dpi, respectively. Functional enrichment of the PDEGs suggests that inducing ethylene production, suppression of photosynthesis, downregulation of polysaccharide metabolism, and weakening of cell wall defenses may contribute to successful infection by R. solanacearum. When comparing in planta and nutrient agar growth of the R. solanacearum, 218 and 1,042 DEGs of R. solanacearum (RDEGs) were detected at 3 and 7 dpi, respectively. Additional analysis of the RDEGs suggested that enhanced starch and sucrose metabolism, and upregulation of virulence factors may promote R. solanacearum colonization. Strikingly, 26 R. solanacearum genes were found to have similar DEG patterns during a variety of host-R. solanacearum interactions. This study provides a foundation for a better understanding of the transcriptional changes during pepper-R. solanacearum interactions and will aid in the discovery of potential susceptibility and virulence factors.
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Affiliation(s)
- Heshan Du
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Jingjing Yang
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Bin Chen
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Xiaofen Zhang
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Xiulan Xu
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Changlong Wen
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Sansheng Geng
- Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, China
- National Engineering Research Center for Vegetables, Beijing 100097, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
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Laili N, Mukaihara T, Matsui H, Yamamoto M, Noutoshi Y, Toyoda K, Ichinose Y. Role of Trehalose Synthesis in Ralstonia syzygii subsp. indonesiensis PW1001 in Inducing Hypersensitive Response on Eggplant (Solanum melongena cv. Senryo-nigou). THE PLANT PATHOLOGY JOURNAL 2021; 37:566-579. [PMID: 34897249 PMCID: PMC8666247 DOI: 10.5423/ppj.oa.06.2021.0087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 06/14/2023]
Abstract
Ralstonia syzygii subsp. indonesiensis (Rsi, former name: Ralstonia solanacearum phylotype IV) PW1001, a causal agent of potato wilt disease, induces hypersensitive response (HR) on its non-host eggplant (Solanum melongena cv. Senryo-nigou). The disaccharide trehalose is involved in abiotic and biotic stress tolerance in many organisms. We found that trehalose is required for eliciting HR on eggplant by plant pathogen Rsi PW1001. In R. solanacearum, it is known that the OtsA/OtsB pathway is the dominant trehalose synthesis pathway, and otsA and otsB encode trehalose-6-phosphate (T6P) synthase and T6P phosphatase, respectively. We generated otsA and otsB mutant strains and found that these mutant strains reduced the bacterial trehalose concentration and HR induction on eggplant leaves compared to wild-type. Trehalose functions intracellularly in Rsi PW1001 because addition of exogenous trehalose did not affect the HR level and ion leakage. Requirement of trehalose in HR induction is not common in R. solanacearum species complex because mutation of otsA in Ralstonia pseudosolanacearum (former name: Ralstonia solanacearum phylotype I) RS1002 did not affect HR on the leaves of its non-host tobacco and wild eggplant Solanum torvum. Further, we also found that each otsA and otsB mutant had reduced ability to grow in a medium containing NaCl and sucrose, indicating that trehalose also has an important role in osmotic stress tolerance.
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Affiliation(s)
- Nur Laili
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
- Research Center for Biology, Research Organization for Life Sciences, National Research and Innovation Agency (BRIN), Jl. Raya Jakarta-Bogor Km. 46, Cibinong, Bogor, West Java 16911,
Indonesia
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS), 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241,
Japan
| | - Hidenori Matsui
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Mikihiro Yamamoto
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Yoshiteru Noutoshi
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Kazuhiro Toyoda
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
| | - Yuki Ichinose
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530,
Japan
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Denne NL, Hiles RR, Kyrysyuk O, Iyer-Pascuzzi AS, Mitra RM. Ralstonia solanacearum Effectors Localize to Diverse Organelles in Solanum Hosts. PHYTOPATHOLOGY 2021; 111:2213-2226. [PMID: 33720750 DOI: 10.1094/phyto-10-20-0483-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Phytopathogenic bacteria secrete type III effector (T3E) proteins directly into host plant cells. T3Es can interact with plant proteins and frequently manipulate plant host physiological or developmental processes. The proper subcellular localization of T3Es is critical for their ability to interact with plant targets, and knowledge of T3E localization can be informative for studies of effector function. Here we investigated the subcellular localization of 19 T3Es from the phytopathogenic bacteria Ralstonia pseudosolanacearum and Ralstonia solanacearum. Approximately 45% of effectors in our library localize to both the plant cell periphery and the nucleus, 15% exclusively to the cell periphery, 15% exclusively to the nucleus, and 25% to other organelles, including tonoplasts and peroxisomes. Using tomato hairy roots, we show that T3E localization is similar in both leaves and roots and is not impacted by Solanum species. We find that in silico prediction programs are frequently inaccurate, highlighting the value of in planta localization experiments. Our data suggest that Ralstonia targets a wide diversity of cellular organelles and provides a foundation for developing testable hypotheses about Ralstonia effector function.
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Affiliation(s)
- Nina L Denne
- Department of Biology, Carleton College, Northfield, MN 55057
| | - Rachel R Hiles
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, IN 47907
| | | | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, IN 47907
| | - Raka M Mitra
- Department of Biology, Carleton College, Northfield, MN 55057
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Pandey A, Moon H, Choi S, Yoon H, Prokchorchik M, Jayaraman J, Sujeevan R, Kang YM, McCann HC, Segonzac C, Kim CM, Park SJ, Sohn KH. Ralstonia solanacearum Type III Effector RipJ Triggers Bacterial Wilt Resistance in Solanum pimpinellifolium. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:962-972. [PMID: 33881922 DOI: 10.1094/mpmi-09-20-0256-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ralstonia solanacearum causes bacterial wilt disease in solanaceous crops. Identification of avirulence type III-secreted effectors recognized by specific disease resistance proteins in host plant species is an important step toward developing durable resistance in crops. In the present study, we show that R. solanacearum effector RipJ functions as an avirulence determinant in Solanum pimpinellifolium LA2093. In all, 10 candidate avirulence effectors were shortlisted based on the effector repertoire comparison between avirulent Pe_9 and virulent Pe_1 strains. Infection assays with transgenic strain Pe_1 individually carrying a candidate avirulence effector from Pe_9 revealed that only RipJ elicits strong bacterial wilt resistance in S. pimpinellifolium LA2093. Furthermore, we identified that several RipJ natural variants do not induce bacterial wilt resistance in S. pimpinellifolium LA2093. RipJ belongs to the YopJ family of acetyltransferases. Our sequence analysis indicated the presence of partially conserved putative catalytic residues. Interestingly, the conserved amino acid residues in the acetyltransferase catalytic triad are not required for effector-triggered immunity. In addition, we show that RipJ does not autoacetylate its lysine residues. Our study reports the identification of the first R. solanacearum avirulence protein that triggers bacterial wilt resistance in tomato. We expect that our discovery of RipJ as an avirulence protein will accelerate the development of bacterial wilt-resistant tomato varieties in the future.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Ankita Pandey
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hayoung Moon
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sera Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hayeon Yoon
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Maxim Prokchorchik
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Germany
| | - Jay Jayaraman
- New Zealand Institute for Plant & Food Research Limited (PFR), Mt Albert Auckland 1025, New Zealand
| | - Rajendran Sujeevan
- Division of Biological Sciences and Research Institute for Basic Science, Wonkwang University, Iksan 54538, Republic of Korea
| | - Yu Mi Kang
- Division of Horticulture Industry, Wonkwang University, Iksan 554438, Republic of Korea
| | - Honour C McCann
- Institute of Advanced Studies, Massey University, Auckland 0745, New Zealand
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Cécile Segonzac
- Department of Plant Science, Plant Genome and Breeding Institute, Agricultural Life Science Research Institute, Seoul National University, 08826, Seoul, Republic of Korea
- Plant Immunity Research Center, Seoul National University, 08826, Seoul, Republic of Korea
- Department of Agriculture, Forestry and Bioresources, Seoul National University, 08826, Seoul, Republic of Korea
| | - Chul Min Kim
- Division of Horticulture Industry, Wonkwang University, Iksan 554438, Republic of Korea
| | - Soon Ju Park
- Division of Biological Sciences and Research Institute for Basic Science, Wonkwang University, Iksan 54538, Republic of Korea
| | - Kee Hoon Sohn
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- School of Interdisciplinary Biosciences and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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Moon H, Pandey A, Yoon H, Choi S, Jeon H, Prokchorchik M, Jung G, Witek K, Valls M, McCann HC, Kim M, Jones JDG, Segonzac C, Sohn KH. Identification of RipAZ1 as an avirulence determinant of Ralstonia solanacearum in Solanum americanum. MOLECULAR PLANT PATHOLOGY 2021; 22:317-333. [PMID: 33389783 PMCID: PMC7865085 DOI: 10.1111/mpp.13030] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/07/2020] [Accepted: 11/23/2020] [Indexed: 05/08/2023]
Abstract
Ralstonia solanacearum causes bacterial wilt disease in many plant species. Type III-secreted effectors (T3Es) play crucial roles in bacterial pathogenesis. However, some T3Es are recognized by corresponding disease resistance proteins and activate plant immunity. In this study, we identified the R. solanacearum T3E protein RipAZ1 (Ralstonia injected protein AZ1) as an avirulence determinant in the black nightshade species Solanum americanum. Based on the S. americanum accession-specific avirulence phenotype of R. solanacearum strain Pe_26, 12 candidate avirulence T3Es were selected for further analysis. Among these candidates, only RipAZ1 induced a cell death response when transiently expressed in a bacterial wilt-resistant S. americanum accession. Furthermore, loss of ripAZ1 in the avirulent R. solanacearum strain Pe_26 resulted in acquired virulence. Our analysis of the natural sequence and functional variation of RipAZ1 demonstrated that the naturally occurring C-terminal truncation results in loss of RipAZ1-triggered cell death. We also show that the 213 amino acid central region of RipAZ1 is sufficient to induce cell death in S. americanum. Finally, we show that RipAZ1 may activate defence in host cell cytoplasm. Taken together, our data indicate that the nucleocytoplasmic T3E RipAZ1 confers R. solanacearum avirulence in S. americanum. Few avirulence genes are known in vascular bacterial phytopathogens and ripAZ1 is the first one in R. solanacearum that is recognized in black nightshades. This work thus opens the way for the identification of disease resistance genes responsible for the specific recognition of RipAZ1, which can be a source of resistance against the devastating bacterial wilt disease.
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Affiliation(s)
- Hayoung Moon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Ankita Pandey
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hayeon Yoon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Sera Choi
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hyelim Jeon
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Maxim Prokchorchik
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Gayoung Jung
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Kamil Witek
- The Sainsbury LaboratoryUniversity of East AngliaNorwichUK
| | - Marc Valls
- Department of GeneticsUniversity of BarcelonaBarcelonaSpain
- Centre for Research in Agricultural Genomics (CSIC‐IRTA‐UAB‐UB)BellaterraSpain
| | - Honour C. McCann
- New Zealand Institute of Advanced StudiesMassey UniversityAucklandNew Zealand
- Max Planck Institute for Developmental BiologyTübingenGermany
| | - Min‐Sung Kim
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- Division of Integrative Biosciences and BiotechnologyPohang University of Science and TechnologyRepublic of Korea
| | | | - Cécile Segonzac
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
- Department of Plant Science, Plant Genomics and Breeding InstituteAgricultural Life Science Research InstituteSeoul National UniversitySeoulRepublic of Korea
| | - Kee Hoon Sohn
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- School of Interdisciplinary Bioscience and BioengineeringPohang University of Science and TechnologyPohangRepublic of Korea
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10
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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: 57] [Impact Index Per Article: 14.3] [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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11
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Sang Y, Yu W, Zhuang H, Wei Y, Derevnina L, Yu G, Luo J, Macho AP. Intra-strain Elicitation and Suppression of Plant Immunity by Ralstonia solanacearum Type-III Effectors in Nicotiana benthamiana. PLANT COMMUNICATIONS 2020; 1:100025. [PMID: 33367244 PMCID: PMC7747989 DOI: 10.1016/j.xplc.2020.100025] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/12/2019] [Accepted: 01/16/2020] [Indexed: 05/11/2023]
Abstract
Effector proteins delivered inside plant cells are powerful weapons for bacterial pathogens, but this exposes the pathogen to potential recognition by the plant immune system. Therefore, the effector repertoire of a given pathogen must be balanced for a successful infection. Ralstonia solanacearum is an aggressive pathogen with a large repertoire of secreted effectors. One of these effectors, RipE1, is conserved in most R. solanacearum strains sequenced to date. In this work, we found that RipE1 triggers immunity in N. benthamiana, which requires the immune regulator SGT1, but not EDS1 or NRCs. Interestingly, RipE1-triggered immunity induces the accumulation of salicylic acid (SA) and the overexpression of several genes encoding phenylalanine-ammonia lyases (PALs), suggesting that the unconventional PAL-mediated pathway is responsible for the observed SA biosynthesis. Surprisingly, RipE1 recognition also induces the expression of jasmonic acid (JA)-responsive genes and JA biosynthesis, suggesting that both SA and JA may act cooperatively in response to RipE1. We further found that RipE1 expression leads to the accumulation of glutathione in plant cells, which precedes the activation of immune responses. R. solanacearum secretes another effector, RipAY, which is known to inhibit immune responses by degrading cellular glutathione. Accordingly, RipAY inhibits RipE1-triggered immune responses. This work shows a strategy employed by R. solanacearum to counteract the perception of its effector proteins by plant immune system.
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Affiliation(s)
- Yuying Sang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Wenjia Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haiyan Zhuang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Yali Wei
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lida Derevnina
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich NR4 7UH, UK
| | - Gang Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
| | - Jiamin Luo
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
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12
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Sun T, Wu W, Wu H, Rou W, Zhou Y, Zhuo T, Fan X, Hu X, Zou H. Ralstonia solanacearum elicitor RipX Induces Defense Reaction by Suppressing the Mitochondrial atpA Gene in Host Plant. Int J Mol Sci 2020; 21:E2000. [PMID: 32183439 PMCID: PMC7139787 DOI: 10.3390/ijms21062000] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 11/16/2022] Open
Abstract
RipX of Ralstonia solanacearum is translocated into host cells by a type III secretion system and acts as a harpin-like protein to induce a hypersensitive response in tobacco plants. The molecular events in association with RipX-induced signaling transduction have not been fully elucidated. This work reports that transient expression of RipX induced a yellowing phenotype in Nicotiana benthamiana, coupled with activation of the defense reaction. Using yeast two-hybrid and split-luciferase complementation assays, mitochondrial ATP synthase F1 subunit α (ATPA) was identified as an interaction partner of RipX from N. benthamiana. Although a certain proportion was found in mitochondria, the YFP-ATPA fusion was able to localize to the cell membrane, cytoplasm, and nucleus. RFP-RipX fusion was found from the cell membrane and cytoplasm. Moreover, ATPA interacted with RipX at both the cell membrane and cytoplasm in vivo. Silencing of the atpA gene had no effect on the appearance of yellowing phenotype induced by RipX. However, the silenced plants improved the resistance to R. solanacearum. Moreover, qRT-PCR and promoter GUS fusion experiments revealed that the transcript levels of atpA were evidently reduced in response to expression of RipX. These data demonstrated that RipX exerts a suppressive effect on the transcription of atpA gene, to induce defense reaction in N. benthamiana.
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Affiliation(s)
- Tingyan Sun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Wei Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Haoxiang Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Wei Rou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Yinghui Zhou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Tao Zhuo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Xiaojing Fan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Xun Hu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
| | - Huasong Zou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (T.S.); (W.W.); (H.W.); (W.R.); (Y.Z.); (T.Z.); (X.F.); (X.H.)
- Fujian University Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
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13
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Lonjon F, Rengel D, Roux F, Henry C, Turner M, Le Ru A, Razavi N, Sabbagh CRR, Genin S, Vailleau F. HpaP Sequesters HrpJ, an Essential Component of Ralstonia solanacearum Virulence That Triggers Necrosis in Arabidopsis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:200-211. [PMID: 31567040 DOI: 10.1094/mpmi-05-19-0139-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The Gram-negative bacterium Ralstonia solanacearum, the causal agent of bacterial wilt, is a worldwide major crop pathogen whose virulence strongly relies on a type III secretion system (T3SS). This extracellular apparatus allows the translocation of proteins, called type III effectors (T3Es), directly into the host cells. To date, very few data are available in plant-pathogenic bacteria concerning the role played by type III secretion (T3S) regulators at the posttranslational level. We have demonstrated that HpaP, a putative T3S substrate specificity switch protein of R. solanacearum, controls T3E secretion. To better understand the role of HpaP on T3S control, we analyzed the secretomes of the GMI1000 wild-type strain as well as the hpaP mutant using a mass spectrometry experiment (liquid chromatography tandem mass spectrometry). The secretomes of both strains appeared to be very similar and highlighted the modulation of the secretion of few type III substrates. Interestingly, only one type III-associated protein, HrpJ, was identified as specifically secreted by the hpaP mutant. HrpJ appeared to be an essential component of the T3SS, essential for T3S and pathogenicity. We further showed that HrpJ is specifically translocated in planta by the hpaP mutant and that HrpJ can physically interact with HpaP. Moreover, confocal microscopy experiments demonstrated a cytoplasmic localization for HrpJ once in planta. When injected into Arabidopsis thaliana leaves, HrpJ is able to trigger a necrosis on 16 natural accessions. A genome-wide association mapping revealed a major association peak with 12 highly significant single-nucleotide polymorphisms located on a plant acyl-transferase.
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Affiliation(s)
- Fabien Lonjon
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - David Rengel
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Fabrice Roux
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Céline Henry
- Micalis Institute, PAPPSO, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Marie Turner
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | - Aurélie Le Ru
- Research Federation "Agrobiosciences, Interactions et Biodiversité" Castanet-Tolosan, France
| | - Narjes Razavi
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
| | | | - Stéphane Genin
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
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14
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Nakano M, Mukaihara T. The type III effector RipB from Ralstonia solanacearum RS1000 acts as a major avirulence factor in Nicotiana benthamiana and other Nicotiana species. MOLECULAR PLANT PATHOLOGY 2019; 20:1237-1251. [PMID: 31218811 PMCID: PMC6715614 DOI: 10.1111/mpp.12824] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Ralstonia solanacearum is the causal agent of bacterial wilt in solanaceous crops. This pathogen injects approximately 70 effector proteins into plant cells via the Hrp type III secretion system in an early stage of infection. To identify an as-yet-unidentified avirulence factor possessed by the Japanese tobacco-avirulent strain RS1000, we transiently expressed RS1000 effectors in Nicotiana benthamiana leaves and monitored their ability to induce effector-triggered immunity (ETI). The expression of RipB strongly induced the production of reactive oxygen species and the expressions of defence-related genes in N. benthamiana. The ripB mutant of RS1002, a nalixidic acid-resistant derivative of RS1000, caused wilting symptoms in N. benthamiana. A pathogenicity test using R. solanacearum mutants revealed that the two already known avirulence factors RipP1 and RipAA contribute in part to the avirulence of RS1002 in N. benthamiana. The Japanese tobacco-virulent strain BK1002 contains mutations in ripB and expresses a C-terminal-truncated RipB that lost the ability to induce ETI in N. benthamiana, indicating a fine-tuning of the pathogen effector repertoire to evade plant recognition. RipB shares homology with Xanthomonas XopQ, which is recognized by the resistance protein Roq1. The RipB-induced resistance against R. solanacearum was abolished in Roq1-silenced plants. These findings indicate that RipB acts as a major avirulence factor in N. benthamiana and that Roq1 is involved in the recognition of RipB.
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Affiliation(s)
- Masahito Nakano
- Research Institute for Biological Sciences, Okayama (RIBS)Yoshikawa, Kibichuo‐choOkayama716‐1241Japan
| | - Takafumi Mukaihara
- Research Institute for Biological Sciences, Okayama (RIBS)Yoshikawa, Kibichuo‐choOkayama716‐1241Japan
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15
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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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16
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Bastedo DP, Lo T, Laflamme B, Desveaux D, Guttman DS. Diversity and Evolution of Type III Secreted Effectors: A Case Study of Three Families. Curr Top Microbiol Immunol 2019; 427:201-230. [DOI: 10.1007/82_2019_165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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17
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Where are we going with genomics in plant pathogenic bacteria? Genomics 2018; 111:729-736. [PMID: 29678682 DOI: 10.1016/j.ygeno.2018.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022]
Abstract
Genome sequencing is commonly used in research laboratories right now thanks to the rise of high-throughput sequencing with higher speed and output-to-cost ratios. Here, we summarized the application of genomics in different aspects of plant bacterial pathosystems. Genomics has been used in studying the mechanisms of plant-bacteria interactions, and host specificity. It also helps with taxonomy, study of non-cultured bacteria, identification of causal agent, single cell sequencing, population genetics, and meta-transcriptomic. Overall, genomics has significantly improved our understanding of plant-microbe interaction.
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18
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Zhang Y, Li J, Zhang W, Shi H, Luo F, Hikichi Y, Shi X, Ohnishi K. A putative LysR-type transcriptional regulator PrhO positively regulates the type III secretion system and contributes to the virulence of Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2018; 19:1808-1819. [PMID: 29363870 PMCID: PMC6638147 DOI: 10.1111/mpp.12660] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/21/2017] [Accepted: 01/20/2018] [Indexed: 06/01/2023]
Abstract
LysR-type transcriptional regulators (LTTRs) are ubiquitous and abundant amongst bacteria and control a variety of cellular processes. Here, we investigated the effect of Rsc1880 (a putative LTTR, hereafter designated as PrhO) on the pathogenicity of Ralstonia solanacearum. Deletion of prhO substantially reduced the expression of the type III secretion system (T3SS) both in vitro and in planta, and resulted in significantly impaired virulence in tomato and tobacco plants. Complementary prhO completely restored the reduced virulence and T3SS expression to that of the wild-type. Moreover, PrhO-dependent T3SS and virulence were conserved amongst R. solanacearum species. However, deletion of prhO did not alter biofilm formation, swimming mobility and in planta growth. The expression of some type III effectors was significantly reduced in prhO mutants, but the hypersensitive response was not affected in tobacco leaves. Consistent with the key regulatory role of HrpB on T3SS, PrhO positively regulated the T3SS through HrpB. Furthermore, PrhO regulated hrpB expression via two close paralogues, HrpG and PrhG, which are two-component response regulators and positively regulate hrpB expression in a parallel manner. However, deletion of prhO did not alter the expression of phcA, prhJ and prhN, which are also involved in hrpB regulation. In addition, PrhO was expressed in a cell density-dependent manner, but negatively repressed by itself. No regulation was observed for HrpB, PhcA and PrhN on prhO expression. Taken together, we genetically demonstrated that PrhO is a novel virulence regulator of R. solanacearum, which positively regulates T3SS expression through HrpG, PrhG and HrpB and contributes to virulence.
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Affiliation(s)
- Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Jiaman Li
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Weiqi Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Hualei Shi
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Feng Luo
- Research Center of Bioenergy and Bioremediation, College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and BiotechnologyKochi UniversityKochi783‐8502Japan
| | - Xiaojun Shi
- College of Resources and EnvironmentSouthwest UniversityChongqing400715China
| | - Kouhei Ohnishi
- Research Institute of Molecular GeneticsKochi UniversityKochi783‐8502Japan
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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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HpaB-Dependent Secretion of Type III Effectors in the Plant Pathogens Ralstonia solanacearum and Xanthomonas campestris pv. vesicatoria. Sci Rep 2017; 7:4879. [PMID: 28687734 PMCID: PMC5501821 DOI: 10.1038/s41598-017-04853-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/10/2017] [Indexed: 01/16/2023] Open
Abstract
Plant pathogenic bacteria exerts their pathogenicity through the injection of large repertoires of type III effectors (T3Es) into plant cells, a mechanism controlled in part by type III chaperones (T3Cs). In Ralstonia solanacearum, the causal agent of bacterial wilt, little is known about the control of type III secretion at the post-translational level. Here, we provide evidence that the HpaB and HpaD proteins do act as bona fide R. solanacearum class IB chaperones that associate with several T3Es. Both proteins can dimerize but do not interact with each other. After screening 38 T3Es for direct interactions, we highlighted specific and common interacting partners, thus revealing the first picture of the R. solanacearum T3C-T3E network. We demonstrated that the function of HpaB is conserved in two phytopathogenic bacteria, R. solanacearum and Xanthomonas campestris pv. vesicatoria (Xcv). HpaB from Xcv is able to functionally complement a R. solanacearum hpaB mutant for hypersensitive response elicitation on tobacco plants. Likewise, Xcv is able to translocate a heterologous T3E from R. solanacearum in an HpaB-dependent manner. This study underlines the central role of the HpaB class IB chaperone family and its potential contribution to the bacterial plasticity to acquire and deliver new virulence factors.
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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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YopJ Family Effectors Promote Bacterial Infection through a Unique Acetyltransferase Activity. Microbiol Mol Biol Rev 2016; 80:1011-1027. [PMID: 27784797 DOI: 10.1128/mmbr.00032-16] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Gram-negative bacterial pathogens rely on the type III secretion system to inject virulence proteins into host cells. These type III secreted "effector" proteins directly manipulate cellular processes to cause disease. Although the effector repertoires in different bacterial species are highly variable, the Yersinia outer protein J (YopJ) effector family is unique in that its members are produced by diverse animal and plant pathogens as well as a nonpathogenic microsymbiont. All YopJ family effectors share a conserved catalytic triad that is identical to that of the C55 family of cysteine proteases. However, an accumulating body of evidence demonstrates that many YopJ effectors modify their target proteins in hosts by acetylating specific serine, threonine, and/or lysine residues. This unique acetyltransferase activity allows the YopJ family effectors to affect the function and/or stability of their targets, thereby dampening innate immunity. Here, we summarize the current understanding of this prevalent and evolutionarily conserved type III effector family by describing their enzymatic activities and virulence functions in animals and plants. In particular, the molecular mechanisms by which representative YopJ family effectors subvert host immunity through posttranslational modification of their target proteins are discussed.
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Deng MY, Sun YH, Li P, Fu B, Shen D, Lu YJ. The phytopathogenic virulent effector protein RipI induces apoptosis in budding yeast Saccharomyces cerevisiae. Toxicon 2016; 121:109-118. [DOI: 10.1016/j.toxicon.2016.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/01/2016] [Accepted: 09/06/2016] [Indexed: 11/28/2022]
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Ailloud F, Lowe TM, Robène I, Cruveiller S, Allen C, Prior P. In planta comparative transcriptomics of host-adapted strains of Ralstonia solanacearum. PeerJ 2016; 4:e1549. [PMID: 26788428 PMCID: PMC4715432 DOI: 10.7717/peerj.1549] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/09/2015] [Indexed: 01/01/2023] Open
Abstract
Background. Ralstonia solanacearum is an economically important plant pathogen with an unusually large host range. The Moko (banana) and NPB (not pathogenic to banana) strain groups are closely related but are adapted to distinct hosts. Previous comparative genomics studies uncovered very few differences that could account for the host range difference between these pathotypes. To better understand the basis of this host specificity, we used RNAseq to profile the transcriptomes of an R. solanacearum Moko strain and an NPB strain under in vitro and in planta conditions. Results. RNAs were sequenced from bacteria grown in rich and minimal media, and from bacteria extracted from mid-stage infected tomato, banana and melon plants. We computed differential expression between each pair of conditions to identify constitutive and host-specific gene expression differences between Moko and NPB. We found that type III secreted effectors were globally up-regulated upon plant cell contact in the NPB strain compared with the Moko strain. Genes encoding siderophore biosynthesis and nitrogen assimilation genes were highly up-regulated in the NPB strain during melon pathogenesis, while denitrification genes were up-regulated in the Moko strain during banana pathogenesis. The relatively lower expression of oxidases and the denitrification pathway during banana pathogenesis suggests that R. solanacearum experiences higher oxygen levels in banana pseudostems than in tomato or melon xylem. Conclusions. This study provides the first report of differential gene expression associated with host range variation. Despite minimal genomic divergence, the pathogenesis of Moko and NPB strains is characterized by striking differences in expression of virulence- and metabolism-related genes.
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Affiliation(s)
- Florent Ailloud
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Centre de coopération International en Recherche Agronomique pour le Développement, Saint-Pierre, France; Laboratoire de la Santé des Végétaux, Agence Nationale Sécurité Sanitaire Alimentaire Nationale, Saint-Pierre, France
| | - Tiffany M Lowe
- Department of Plant Pathology, University of Wisconsin-Madison , Madison, WI , United States
| | - Isabelle Robène
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Centre de coopération International en Recherche Agronomique pour le Développement , Saint-Pierre , France
| | - Stéphane Cruveiller
- Laboratoire d'Analyses Bioinformatiques pour la Genomique et le Metabolisme, Commissariat à l'Energie Atomique et aux Energies Alternatives, Evry, France; UMR CNRS 8030 - Génomique Métabolique, Centre National de la Recherche Scientifique, Evry, France
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison , Madison, WI , United States
| | - Philippe Prior
- UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Centre de coopération International en Recherche Agronomique pour le Développement, Saint-Pierre, France; Département de Santé des Plantes et Environnement, Institut National de la Recherche Agronomique, Sophia Antipolis, France
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Lonjon F, Turner M, Henry C, Rengel D, Lohou D, van de Kerkhove Q, Cazalé AC, Peeters N, Genin S, Vailleau F. Comparative Secretome Analysis of Ralstonia solanacearum Type 3 Secretion-Associated Mutants Reveals a Fine Control of Effector Delivery, Essential for Bacterial Pathogenicity. Mol Cell Proteomics 2015; 15:598-613. [PMID: 26637540 DOI: 10.1074/mcp.m115.051078] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Indexed: 12/21/2022] Open
Abstract
Ralstonia solanacearum, the causal agent of bacterial wilt, exerts its pathogenicity through more than a hundred secreted proteins, many of them depending directly on the functionality of a type 3 secretion system. To date, only few type 3 effectors have been identified as required for bacterial pathogenicity, notably because of redundancy among the large R. solanacearum effector repertoire. In order to identify groups of effectors collectively promoting disease on susceptible hosts, we investigated the role of putative post-translational regulators in the control of type 3 secretion. A shotgun secretome analysis with label-free quantification using tandem mass spectrometry was performed on the R. solanacearum GMI1000 strain. There were 228 proteins identified, among which a large proportion of type 3 effectors, called Rip (Ralstonia injected proteins). Thanks to this proteomic approach, RipBJ was identified as a new effector specifically secreted through type 3 secretion system and translocated into plant cells. A focused Rip secretome analysis using hpa (hypersensitive response and pathogenicity associated) mutants revealed a fine secretion regulation and specific subsets of Rips with different secretion patterns. We showed that a set of Rips (RipF1, RipW, RipX, RipAB, and RipAM) are secreted in an Hpa-independent manner. We hypothesize that these Rips could be preferentially involved in the first stages of type 3 secretion. In addition, the secretion of about thirty other Rips is controlled by HpaB and HpaG. HpaB, a candidate chaperone was shown to positively control secretion of numerous Rips, whereas HpaG was shown to act as a negative regulator of secretion. To evaluate the impact of altered type 3 effectors secretion on plant pathogenesis, the hpa mutants were assayed on several host plants. HpaB was required for bacterial pathogenicity on multiple hosts whereas HpaG was found to be specifically required for full R. solanacearum pathogenicity on the legume plant Medicago truncatula.
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Affiliation(s)
- Fabien Lonjon
- From the ‡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
| | - Marie Turner
- From the ‡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
| | - Céline Henry
- ¶PAPPSO, Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - David Rengel
- From the ‡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
| | - David Lohou
- From the ‡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
| | - Quitterie van de Kerkhove
- From the ‡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
| | - Anne-Claire Cazalé
- From the ‡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
| | - Nemo Peeters
- From the ‡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
| | - Stéphane Genin
- From the ‡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
| | - Fabienne Vailleau
- From the ‡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; ‖Université de Toulouse; INP; ENSAT; 18 chemin de Borde Rouge, Castanet Tolosan, 31326, France
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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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27
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Bae C, Han SW, Song YR, Kim BY, Lee HJ, Lee JM, Yeam I, Heu S, Oh CS. Infection processes of xylem-colonizing pathogenic bacteria: possible explanations for the scarcity of qualitative disease resistance genes against them in crops. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:1219-29. [PMID: 25917599 DOI: 10.1007/s00122-015-2521-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/17/2015] [Indexed: 05/22/2023]
Abstract
Disease resistance against xylem-colonizing pathogenic bacteria in crops. Plant pathogenic bacteria cause destructive diseases in many commercially important crops. Among these bacteria, eight pathogens, Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, Erwinia amylovora, Pantoea stewartii subsp. stewartii, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. actinidiae, and Xylella fastidiosa, infect their host plants through different infection sites and paths and eventually colonize the xylem tissues of their host plants, resulting in wilting symptoms by blocking water flow or necrosis of xylem tissues. Noticeably, only a relatively small number of resistant cultivars in major crops against these vascular bacterial pathogens except X. oryzae pv. oryzae have been found or generated so far, although these pathogens threaten productivity of major crops. In this review, we summarize the lifestyles of major xylem-colonizing bacterial pathogens and then discuss the progress of current research on disease resistance controlled by qualitative disease resistance genes or quantitative trait loci against them. Finally, we propose infection processes of xylem-colonizing bacterial pathogens as one of possible reasons for why so few qualitative disease resistance genes against these pathogens have been developed or identified so far in crops.
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Affiliation(s)
- Chungyun Bae
- Department of Horticultural Biotechnology and Institute of Life Science and Resources, College of Life Science, Kyung Hee University, Yongin, 446-701, Korea
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28
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Ailloud F, Lowe T, Cellier G, Roche D, Allen C, Prior P. Comparative genomic analysis of Ralstonia solanacearum reveals candidate genes for host specificity. BMC Genomics 2015; 16:270. [PMID: 25888333 PMCID: PMC4396162 DOI: 10.1186/s12864-015-1474-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/20/2015] [Indexed: 12/02/2022] Open
Abstract
Background Ralstonia solanacearum is a vascular soil-borne plant pathogen with an unusually broad host range. This economically destructive and globally distributed bacterium has thousands of distinct lineages within a heterogeneous and taxonomically disputed species complex. Some lineages include highly host-adapted strains (ecotypes), such as the banana Moko disease-causing strains, the cold-tolerant potato brown rot strains (also known as R3bv2) and the recently emerged Not Pathogenic to Banana (NPB) strains. Results These distinct ecotypes offer a robust model to study host adaptation and the emergence of ecotypes because the polyphyletic Moko strains include lineages that are phylogenetically close to the monophyletic brown rot and NPB strains. Draft genomes of eight new strains belonging to these three model ecotypes were produced to complement the eleven publicly available R. solanacearum genomes. Using a suite of bioinformatics methods, we searched for genetic and evolutionary features that distinguish ecotypes and propose specific hypotheses concerning mechanisms of host adaptation in the R. solanacearum species complex. Genome-wide, few differences were identified, but gene loss events, non-synonymous polymorphisms, and horizontal gene transfer were identified among type III effectors and were associated with host range differences. Conclusions This extensive comparative genomics analysis uncovered relatively few divergent features among closely related strains with contrasting biological characteristics; however, several virulence factors were associated with the emergence of Moko, NPB and brown rot and could explain host adaptation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1474-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Florent Ailloud
- CIRAD, UMR PVBMT, F-97410, Saint-Pierre, La Réunion, France. .,Anses - Plant Health Laboratory, F-97410, Saint-Pierre, La Réunion, France.
| | - Tiffany Lowe
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Gilles Cellier
- Anses - Plant Health Laboratory, F-97410, Saint-Pierre, La Réunion, France.
| | - David Roche
- Institut de Génomique, Genoscope, Commissariat à l'Energie Atomique (CEA), Evry, Paris, France.
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Philippe Prior
- CIRAD, UMR PVBMT, F-97410, Saint-Pierre, La Réunion, France. .,Département de Santé des Plantes et Environnement, (SPE) Inra, Paris, France.
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Ailloud F, Lowe T, Cellier G, Roche D, Allen C, Prior P. Comparative genomic analysis of Ralstonia solanacearum reveals candidate genes for host specificity. BMC Genomics 2015. [PMID: 25888333 DOI: 10.1186/s12864-015-1474-1478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND Ralstonia solanacearum is a vascular soil-borne plant pathogen with an unusually broad host range. This economically destructive and globally distributed bacterium has thousands of distinct lineages within a heterogeneous and taxonomically disputed species complex. Some lineages include highly host-adapted strains (ecotypes), such as the banana Moko disease-causing strains, the cold-tolerant potato brown rot strains (also known as R3bv2) and the recently emerged Not Pathogenic to Banana (NPB) strains. RESULTS These distinct ecotypes offer a robust model to study host adaptation and the emergence of ecotypes because the polyphyletic Moko strains include lineages that are phylogenetically close to the monophyletic brown rot and NPB strains. Draft genomes of eight new strains belonging to these three model ecotypes were produced to complement the eleven publicly available R. solanacearum genomes. Using a suite of bioinformatics methods, we searched for genetic and evolutionary features that distinguish ecotypes and propose specific hypotheses concerning mechanisms of host adaptation in the R. solanacearum species complex. Genome-wide, few differences were identified, but gene loss events, non-synonymous polymorphisms, and horizontal gene transfer were identified among type III effectors and were associated with host range differences. CONCLUSIONS This extensive comparative genomics analysis uncovered relatively few divergent features among closely related strains with contrasting biological characteristics; however, several virulence factors were associated with the emergence of Moko, NPB and brown rot and could explain host adaptation.
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Affiliation(s)
- Florent Ailloud
- CIRAD, UMR PVBMT, F-97410, Saint-Pierre, La Réunion, France.
- Anses - Plant Health Laboratory, F-97410, Saint-Pierre, La Réunion, France.
| | - Tiffany Lowe
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Gilles Cellier
- Anses - Plant Health Laboratory, F-97410, Saint-Pierre, La Réunion, France.
| | - David Roche
- Institut de Génomique, Genoscope, Commissariat à l'Energie Atomique (CEA), Evry, Paris, France.
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Philippe Prior
- CIRAD, UMR PVBMT, F-97410, Saint-Pierre, La Réunion, France.
- Département de Santé des Plantes et Environnement, (SPE) Inra, Paris, France.
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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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Lohou D, Turner M, Lonjon F, Cazalé AC, Peeters N, Genin S, Vailleau F. HpaP modulates type III effector secretion in Ralstonia solanacearum and harbours a substrate specificity switch domain essential for virulence. MOLECULAR PLANT PATHOLOGY 2014; 15:601-14. [PMID: 24405562 PMCID: PMC6638691 DOI: 10.1111/mpp.12119] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Many pathogenic bacteria have evolved a type III secretion system (T3SS) to successfully invade their host. This extracellular apparatus allows the translocation of proteins, called type III effectors (T3Es), directly into the host cells. T3Es are virulence factors that have been shown to interfere with the host's immunity or to provide nutrients from the host to the bacteria. The Gram-negative bacterium Ralstonia solanacearum is a worldwide major crop pest whose virulence strongly relies on the T3SS. In R. solanacearum, transcriptional regulation has been extensively studied. However, very few data are available concerning the role played by type III-associated regulators, such as type III chaperones and T3SS control proteins. Here, we characterized HpaP, a putative type III secretion substrate specificity switch (T3S4) protein of R. solanacearum which is not secreted by the bacterium or translocated in the plant cells. HpaP self-interacts and interacts with the PopP1 T3E. HpaP modulates the secretion of early (HrpY pilin) and late (AvrA and PopP1 T3Es) type III substrates. HpaP is dispensable for the translocation of T3Es into the host cells. Finally, we identified two regions of five amino acids in the T3S4 domain that are essential for efficient PopP1 secretion and for HpaP's role in virulence on tomato and Arabidopsis thaliana, but not required for HpaP-HpaP and HpaP-PopP1 interactions. Taken together, our results indicate that HpaP is a putative R. solanacearum T3S4 protein important for full pathogenicity on several hosts, acting as a helper for PopP1 secretion, and repressing AvrA and HrpY secretion.
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Affiliation(s)
- David Lohou
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), INRA, UMR441, F-31326, Castanet-Tolosan, France; Laboratoire des Interactions Plantes-Microorganismes (LIPM), CNRS, UMR2594, F-31326, 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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Peeters N, Carrère S, Anisimova M, Plener L, Cazalé AC, Genin S. Repertoire, unified nomenclature and evolution of the Type III effector gene set in the Ralstonia solanacearum species complex. BMC Genomics 2013; 14:859. [PMID: 24314259 PMCID: PMC3878972 DOI: 10.1186/1471-2164-14-859] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 11/29/2013] [Indexed: 12/21/2022] Open
Abstract
Background Ralstonia solanacearum is a soil-borne beta-proteobacterium that causes bacterial wilt disease in many food crops and is a major problem for agriculture in intertropical regions. R. solanacearum is a heterogeneous species, both phenotypically and genetically, and is considered as a species complex. Pathogenicity of R. solanacearum relies on the Type III secretion system that injects Type III effector (T3E) proteins into plant cells. T3E collectively perturb host cell processes and modulate plant immunity to enable bacterial infection. Results We provide the catalogue of T3E in the R. solanacearum species complex, as well as candidates in newly sequenced strains. 94 T3E orthologous groups were defined on phylogenetic bases and ordered using a uniform nomenclature. This curated T3E catalog is available on a public website and a bioinformatic pipeline has been designed to rapidly predict T3E genes in newly sequenced strains. Systematical analyses were performed to detect lateral T3E gene transfer events and identify T3E genes under positive selection. Our analyses also pinpoint the RipF translocon proteins as major discriminating determinants among the phylogenetic lineages. Conclusions Establishment of T3E repertoires in strains representatives of the R. solanacearum biodiversity allowed determining a set of 22 T3E present in all the strains but provided no clues on host specificity determinants. The definition of a standardized nomenclature and the optimization of predictive tools will pave the way to understanding how variation of these repertoires is correlated to the diversification of this species complex and how they contribute to the different strain pathotypes.
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Affiliation(s)
- Nemo Peeters
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France.
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Yamada T. Filamentous phages of Ralstonia solanacearum: double-edged swords for pathogenic bacteria. Front Microbiol 2013; 4:325. [PMID: 24204365 PMCID: PMC3816273 DOI: 10.3389/fmicb.2013.00325] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/14/2013] [Indexed: 12/20/2022] Open
Abstract
Some phages from genus Inovirus use host or bacteriophage-encoded site-specific integrases or recombinases establish a prophage state. During integration or excision, a superinfective form can be produced. The three states (free, prophage, and superinfective) of such phages exert different effects on host bacterial phenotypes. In Ralstonia solanacearum, the causative agent of bacterial wilt disease of crops, the bacterial virulence can be positively or negatively affected by filamentous phages, depending on their state. The presence or absence of a repressor gene in the phage genome may be responsible for the host phenotypic differences (virulent or avirulent) caused by phage infection. This strategy of virulence control may be widespread among filamentous phages that infect pathogenic bacteria of plants.
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Affiliation(s)
- Takashi Yamada
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University Higashi-Hiroshima, Japan
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Peeters N, Guidot A, Vailleau F, Valls M. Ralstonia solanacearum, a widespread bacterial plant pathogen in the post-genomic era. MOLECULAR PLANT PATHOLOGY 2013; 14:651-62. [PMID: 23718203 PMCID: PMC6638647 DOI: 10.1111/mpp.12038] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
UNLABELLED Ralstonia solanacearum is a soil-borne bacterium causing the widespread disease known as bacterial wilt. Ralstonia solanacearum is also the causal agent of Moko disease of banana and brown rot of potato. Since the last R. solanacearum pathogen profile was published 10 years ago, studies concerning this plant pathogen have taken a genomic and post-genomic direction. This was pioneered by the first sequenced and annotated genome for a major plant bacterial pathogen and followed by many more genomes in subsequent years. All molecular features studied now have a genomic flavour. In the future, this will help in connecting the classical field of pathology and diversity studies with the gene content of specific strains. In this review, we summarize the recent research on this bacterial pathogen, including strain classification, host range, pathogenicity determinants, regulation of virulence genes, type III effector repertoire, effector-triggered immunity, plant signalling in response to R. solanacearum, as well as a review of different new pathosystems. TAXONOMY Bacteria; Proteobacteria; β subdivision; Ralstonia group; genus Ralstonia. DISEASE SYMPTOMS Ralstonia solanacearum is the agent of bacterial wilt of plants, characterized by a sudden wilt of the whole plant. Typically, stem cross-sections will ooze a slimy bacterial exudate. In the case of Moko disease of banana and brown rot of potato, there is also visible bacterial colonization of banana fruit and potato tuber. DISEASE CONTROL As a soil-borne pathogen, infected fields can rarely be reused, even after rotation with nonhost plants. The disease is controlled by the use of resistant and tolerant plant cultivars. The prevention of spread of the disease has been achieved, in some instances, by the application of strict prophylactic sanitation practices. USEFUL WEBSITES Stock centre: International Centre for Microbial Resources-French Collection for Plant-associated Bacteria CIRM-CFBP, IRHS UMR 1345 INRA-ACO-UA, 42 rue Georges Morel, 49070 Beaucouzé Cedex, France, http://www.angers-nantes.inra.fr/cfbp/. Ralstonia Genome browser: https://iant.toulouse.inra.fr/R.solanacearum. GMI1000 insertion mutant library: https://iant.toulouse.inra.fr/R.solanacearumGMI1000/GenomicResources. MaGe Genome Browser: https://www.genoscope.cns.fr/agc/microscope/mage/viewer.php?
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Affiliation(s)
- Nemo Peeters
- INRA UMR441 Laboratoire des Interactions Plantes Micro-organismes (LIPM), 24 chemin de Borde Rouge-Auzeville CS 52627, 31326, Castanet Tolosan Cedex, France
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Coll NS, Valls M. Current knowledge on the Ralstonia solanacearum type III secretion system. Microb Biotechnol 2013; 6:614-20. [PMID: 23617636 PMCID: PMC3815929 DOI: 10.1111/1751-7915.12056] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- Núria S Coll
- Centre for Research in Agricultural Genomics (CRAG).Edifici CRAG, Campus UAB, 08193, Bellaterra, Catalonia, Spain
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Van der Linden L, Bredenkamp J, Naidoo S, Fouché-Weich J, Denby KJ, Genin S, Marco Y, Berger DK. Gene-for-gene tolerance to bacterial wilt in Arabidopsis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:398-406. [PMID: 23234403 DOI: 10.1094/mpmi-07-12-0188-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Bacterial wilt caused by Ralstonia solanacearum is a disease of widespread economic importance that affects numerous plant species, including Arabidopsis thaliana. We describe a pathosystem between A. thaliana and biovar 3 phylotype I strain BCCF402 of R. solanacearum isolated from Eucalyptus trees. A. thaliana accession Be-0 was susceptible and accession Kil-0 was tolerant. Kil-0 exhibited no wilting symptoms and no significant reduction in fitness (biomass, seed yield, and germination efficiency) after inoculation with R. solanacearum BCCF402, despite high bacterial numbers in planta. This was in contrast to the well-characterized resistance response in the accession Nd-1, which limits bacterial multiplication at early stages of infection and does not wilt. R. solanacearum BCCF402 was highly virulent because the susceptible accession Be-0 was completely wilted after inoculation. Genetic analyses, allelism studies with Nd-1, and RRS1 cleaved amplified polymorphic sequence marker analysis showed that the tolerance phenotype in Kil-0 was dependent upon the resistance gene RRS1. Knockout and complementation studies of the R. solanacearum BCCF402 effector PopP2 confirmed that the tolerance response in Kil-0 was dependent upon the RRS1-PopP2 interaction. Our data indicate that the gene-for-gene interaction between RRS1 and PopP2 can contribute to tolerance, as well as resistance, which makes it a useful model system for evolutionary studies of the arms race between plants and bacterial pathogens. In addition, the results alert biotechnologists to the risk that deployment of RRS1 in transgenic crops may result in persistence of the pathogen in the field.
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Affiliation(s)
- Liesl Van der Linden
- Department of Plant Science, Forestry and Agricultural Research Institute, South Africa
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Solé M, Popa C, Mith O, Sohn KH, Jones JDG, Deslandes L, Valls M. The awr gene family encodes a novel class of Ralstonia solanacearum type III effectors displaying virulence and avirulence activities. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:941-53. [PMID: 22414437 DOI: 10.1094/mpmi-12-11-0321] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present here the characterization of a new gene family, awr, found in all sequenced Ralstonia solanacearum strains and in other bacterial pathogens. We demonstrate that the five paralogues in strain GMI1000 encode type III-secreted effectors and that deletion of all awr genes severely impairs its capacity to multiply in natural host plants. Complementation studies show that the AWR (alanine-tryptophan-arginine tryad) effectors display some functional redundancy, although AWR2 is the major contributor to virulence. In contrast, the strain devoid of all awr genes (Δawr1-5) exhibits enhanced pathogenicity on Arabidopsis plants. A gain-of-function approach expressing AWR in Pseudomonas syringae pv. tomato DC3000 proves that this is likely due to effector recognition, because AWR5 and AWR4 restrict growth of this bacterium in Arabidopsis. Transient overexpression of AWR in nonhost tobacco species caused macroscopic cell death to varying extents, which, in the case of AWR5, shows characteristics of a typical hypersensitive response. Our work demonstrates that AWR, which show no similarity to any protein with known function, can specify either virulence or avirulence in the interaction of R. solanacearum with its plant hosts.
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Affiliation(s)
- Montserrat Solé
- Department of Genètica, Universitat de Barcelona, Barcelona, Spain
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Metabolic adaptation of Ralstonia solanacearum during plant infection: a methionine biosynthesis case study. PLoS One 2012; 7:e36877. [PMID: 22615832 PMCID: PMC3353975 DOI: 10.1371/journal.pone.0036877] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/13/2012] [Indexed: 11/19/2022] Open
Abstract
MetE and MetH are two distinct enzymes that catalyze a similar biochemical reaction during the last step of methionine biosynthesis, MetH being a cobalamin-dependent enzyme whereas MetE activity is cobalamin-independent. In this work, we show that the last step of methionine synthesis in the plant pathogen Ralstonia solanacearum is under the transcriptional control of the master pathogenicity regulator HrpG. This control is exerted essentially on metE expression through the intermediate regulator MetR. Expression of metE is strongly and specifically induced in the presence of plant cells in a hrpG- and metR-dependent manner. metE and metR mutants are not auxotrophic for methionine and not affected for growth inside the plant but produce significantly reduced disease symptoms on tomato whereas disruption of metH has no impact on pathogenicity. The finding that the pathogen preferentially induces metE expression rather than metH in the presence of plant cells is indicative of a probable metabolic adaptation to physiological host conditions since this induction of metE occurs in an environment in which cobalamin, the required co-factor for MetH, is absent. It also shows that MetE and MetH are not functionally redundant and are deployed during specific stages of the bacteria lifecycle, the expression of metE and metH being controlled by multiple and distinct signals.
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Addy HS, Askora A, Kawasaki T, Fujie M, Yamada T. The filamentous phage ϕRSS1 enhances virulence of phytopathogenic Ralstonia solanacearum on tomato. PHYTOPATHOLOGY 2012; 102:244-51. [PMID: 22085298 DOI: 10.1094/phyto-10-11-0277] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Ralstonia solanacearum is the causative agent of bacterial wilt in many important crops. ϕRSS1 is a filamentous phage that infects R. solanacearum strains. Upon infection, it alters the physiological state and the behavior of host cells. Here, we show that R. solanacearum infected by ϕRSS1 becomes more virulent on host plants. Some virulence and pathogenicity factors, such as extracellular polysaccharide (EPS) synthesis and twitching motility, increased in the bacterial host cells infected with ϕRSS1, resulting in early wilting. Tomato plants inoculated with ϕRSS1-infected bacteria wilted 2 to 3 days earlier than those inoculated with wild-type bacteria. Infection with ϕRSS1 induced early expression of phcA, the global virulence regulator. phcA expression was detected in ϕRSS1-infected cells at cell density as low as 10(4) CFU/ml. Filamentous phages are assembled on the host cell surface and many phage particles accumulate on the cell surface. These surface-associated phage particles (phage proteins) may change the cell surface nature (hydrophobicity) to give high local cell densities. ϕRSS1 infection also enhanced PilA and type IV pilin production, resulting in increased twitching motility.
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Affiliation(s)
- Hardian S Addy
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8530, Japan
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Genin S, Denny TP. Pathogenomics of the Ralstonia solanacearum species complex. ANNUAL REVIEW OF PHYTOPATHOLOGY 2012; 50:67-89. [PMID: 22559068 DOI: 10.1146/annurev-phyto-081211-173000] [Citation(s) in RCA: 332] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Ralstonia solanacearum is a major phytopathogen that attacks many crops and other plants over a broad geographical range. The extensive genetic diversity of strains responsible for the various bacterial wilt diseases has in recent years led to the concept of an R. solanacearum species complex. Genome sequencing of more than 10 strains representative of the main phylogenetic groups has broadened our knowledge of the evolution and speciation of this pathogen and led to the identification of novel virulence-associated functions. Comparative genomic analyses are now opening the way for refined functional studies. The many molecular determinants involved in pathogenicity and host-range specificity are described, and we also summarize current understanding of their roles in pathogenesis and how their expression is tightly controlled by an intricate virulence regulatory network.
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Affiliation(s)
- Stéphane Genin
- INRA, Laboratoire des Interactions Plantes-Microorganismes, UMR441, F-31326 Castanet-Tolosan, France.
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Lewis JD, Lee A, Ma W, Zhou H, Guttman DS, Desveaux D. The YopJ superfamily in plant-associated bacteria. MOLECULAR PLANT PATHOLOGY 2011; 12:928-37. [PMID: 21726386 PMCID: PMC6640427 DOI: 10.1111/j.1364-3703.2011.00719.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Bacterial pathogens employ the type III secretion system to secrete and translocate effector proteins into their hosts. The primary function of these effector proteins is believed to be the suppression of host defence responses or innate immunity. However, some effector proteins may be recognized by the host and consequently trigger a targeted immune response. The YopJ/HopZ/AvrRxv family of bacterial effector proteins is a widely distributed and evolutionarily diverse family, found in both animal and plant pathogens, as well as plant symbionts. How can an effector family effectively promote the virulence of pathogens on hosts from two separate kingdoms? Our understanding of the evolutionary relationships among the YopJ superfamily members provides an excellent opportunity to address this question and to investigate the functions and virulence strategies of a diverse type III effector family in animal and plant hosts. In this work, we briefly review the literature on YopJ, the archetypal member from Yersinia pestis, and discuss members of the superfamily in species of Pseudomonas, Xanthomonas, Ralstonia and Rhizobium. We review the molecular and cellular functions, if known, of the YopJ homologues in plants, and highlight the diversity of responses in different plant species, with a particular focus on the Pseudomonas syringae HopZ family. The YopJ superfamily provides an excellent foundation for the study of effector diversification in the context of wide-ranging, co-evolutionary interactions.
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Affiliation(s)
- Jennifer D Lewis
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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Asselin JE, Bonasera JM, Kim JF, Oh CS, Beer SV. Eop1 from a Rubus strain of Erwinia amylovora functions as a host-range limiting factor. PHYTOPATHOLOGY 2011; 101:935-944. [PMID: 21469934 DOI: 10.1094/phyto-12-10-0339] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Strains of Erwinia amylovora, the bacterium causing the disease fire blight of rosaceous plants, are separated into two groups based on host range: Spiraeoideae and Rubus strains. Spiraeoideae strains have wide host ranges, infecting plants in many rosaceous genera, including apple and pear. In the field, Rubus strains infect the genus Rubus exclusively, which includes raspberry and blackberry. Based on comparisons of limited sequence data from a Rubus and a Spiraeoideae strain, the gene eop1 was identified as unusually divergent, and it was selected as a possible host specificity factor. To test this, eop1 genes from a Rubus strain and a Spiraeoideae strain were cloned and mutated. Expression of the Rubus-strain eop1 reduced the virulence of E. amylovora in immature pear fruit and in apple shoots. Sequencing the orfA-eop1 regions of several strains of E. amylovora confirmed that forms of eop1 are conserved among strains with similar host ranges. This work provides evidence that eop1 from a Rubus-specific strain can function as a determinant of host specificity in E. amylovora.
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Affiliation(s)
- J E Asselin
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
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Perrett CA, Lin DYW, Zhou D. Interactions of bacterial proteins with host eukaryotic ubiquitin pathways. Front Microbiol 2011; 2:143. [PMID: 21772834 PMCID: PMC3131157 DOI: 10.3389/fmicb.2011.00143] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 06/16/2011] [Indexed: 12/20/2022] Open
Abstract
Ubiquitination is a post-translational modification in which one or more 76 amino acid polypeptide ubiquitin molecules are covalently linked to the lysine residues of target proteins. Ubiquitination is the main pathway for protein degradation that governs a variety of eukaryotic cellular processes, including the cell-cycle, vesicle trafficking, antigen presentation, and signal transduction. Not surprisingly, aberrations in the system have been implicated in the pathogenesis of many diseases including inflammatory and neurodegenerative disorders. Recent studies have revealed that viruses and bacterial pathogens exploit the host ubiquitination pathways to gain entry and to aid their survival/replication inside host cells. This review will summarize recent developments in understanding the biochemical and structural mechanisms utilized by bacterial pathogens to interact with the host ubiquitination pathways.
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Affiliation(s)
| | - David Yin-Wei Lin
- Department of Biological Sciences, Purdue UniversityWest Lafayette, IN, USA
| | - Daoguo Zhou
- Department of Biological Sciences, Purdue UniversityWest Lafayette, IN, USA
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Jeong Y, Cheong H, Choi O, Kim JK, Kang Y, Kim J, Lee S, Koh S, Moon JS, Hwang I. An HrpB-dependent but type III-independent extracellular aspartic protease is a virulence factor of Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2011; 12:373-80. [PMID: 21453432 PMCID: PMC6640462 DOI: 10.1111/j.1364-3703.2010.00679.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The host specificity of Ralstonia solanacearum, the causal organism of bacterial wilt on many solanaceous crops, is poorly understood. To identify a gene conferring host specificity of the bacterium, SL341 (virulent to hot pepper but avirulent to potato) and SL2029 (virulent to potato but avirulent to hot pepper) were chosen as representative strains. We identified a gene, rsa1, from SL2029 that confers avirulence to SL341 in hot pepper. The rsa1 gene encoding an 11.8-kDa protein possessed the perfect consensus hrp(II) box motif upstream of the gene. Although the expression of rsa1 was activated by HrpB, a transcriptional activator for hrp gene expression, Rsa1 protein was secreted in an Hrp type III secretion-independent manner. Rsa1 exhibited weak homology with an aspartic protease, cathepsin D, and possessed protease activity. Two specific aspartic protease inhibitors, pepstatin A and diazoacetyl-d,l-norleucine methyl ester, inhibited the protease activity of Rsa1. Substitution of two aspartic acid residues with alanine at positions 54 and 59 abolished protease activity. The SL2029 rsa1 mutant was much less virulent than the wild-type strain, but did not induce disease symptoms in hot pepper. These data indicate that Rsa1 is an extracellular aspartic protease and plays an important role for the virulence of SL2029 in potato.
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Affiliation(s)
- Yeonhwa Jeong
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
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Mukaihara T, Tamura N, Iwabuchi M. Genome-wide identification of a large repertoire of Ralstonia solanacearum type III effector proteins by a new functional screen. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:251-62. [PMID: 20121447 DOI: 10.1094/mpmi-23-3-0251] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The gram-negative plant-pathogenic bacterium Ralstonia solanacearum utilizes the hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS) to cause disease in plants. To determine the entire repertoire of effector proteins possessed by R. solanacearum RS1000, we constructed a transposon carrying a calmodulin-dependent adenylate cyclase reporter that can be used to specifically detect rip (Ralstonia protein injected into plant cells) genes by monitoring the cAMP level in plant leaves inoculated with insertion mutants. From the new functional screen using this transposon, we identified 38 new Rip proteins translocated into plant cells via the Hrp T3SS. In addition, most of the 34 known effectors of RS1000 could be detected by the screen, except for three effectors that appear to be small in size or only weakly expressed. Finally, we identified 72 Rips in RS1000, which include 68 effector proteins classified into over 50 families and four extracellular components of the Hrp T3SS. Interestingly, one-third of the effectors are specific to R. solanacearum. Many effector proteins contain various repeated amino acid sequences or known enzyme motifs. We also show that most of the R. solanacearum effector proteins, but not Hrp extracellular components, require an Hrp-associated protein, HpaB, for their effective translocation into plant cells.
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Affiliation(s)
- Takafumi Mukaihara
- Agricultural Experimental Station, Okayama Prefectural General Agriculture Center, 1174-1 Koda-Oki, Akaiwa 709-0801, Japan.
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Turner M, Jauneau A, Genin S, Tavella MJ, Vailleau F, Gentzbittel L, Jardinaud MF. Dissection of bacterial Wilt on Medicago truncatula revealed two type III secretion system effectors acting on root infection process and disease development. PLANT PHYSIOLOGY 2009; 150:1713-22. [PMID: 19493968 PMCID: PMC2719136 DOI: 10.1104/pp.109.141523] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 05/28/2009] [Indexed: 05/20/2023]
Abstract
Ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease, which colonizes susceptible Medicago truncatula via the intact root tip. Infection involves four steps: appearance of root tip symptoms, root tip cortical cell invasion, vessel colonization, and foliar wilting. We examined this pathosystem by in vitro inoculation of intact roots of susceptible or resistant M. truncatula with the pathogenic strain GMI1000. The infection process was type III secretion system dependent and required two type III effectors, Gala7 and AvrA, which were shown to be involved at different stages of infection. Both effectors were involved in development of root tip symptoms, and Gala7 was the main determinant for bacterial invasion of cortical cells. Vessel invasion depended on the host genetic background and was never observed in the resistant line. The invasion of the root tip vasculature in the susceptible line caused foliar wilting. The avrA mutant showed reduced aggressiveness in all steps of the infection process, suggesting a global role in R. solanacearum pathogenicity. The roles of these two effectors in subsequent stages were studied using an assay that bypassed the penetration step; with this assay, the avrA mutant showed no effect compared with the GMI1000 strain, indicating that AvrA is important in early stages of infection. However, later disease symptoms were reduced in the gala7 mutant, indicating a key role in later stages of infection.
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Affiliation(s)
- Marie Turner
- Université de Toulouse, INPT, Laboratoire Symbiose et Pathologie des Plantes, ENSAT, BP 31607 Auzeville-Tolosane, 31326 Castanet-Tolosan, France
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Poueymiro M, Cunnac S, Barberis P, Deslandes L, Peeters N, Cazale-Noel AC, Boucher C, Genin S. Two type III secretion system effectors from Ralstonia solanacearum GMI1000 determine host-range specificity on tobacco. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:538-50. [PMID: 19348572 DOI: 10.1094/mpmi-22-5-0538] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The model pathogen Ralstonia solanacearum GMI1000 is the causal agent of the bacterial wilt disease that attacks many solanaceous plants and other hosts but not tobacco (Nicotiana spp.). We found that two type III secretion system effector genes, avrA and popP1, are limiting the host range of strain GMI1000 on at least three tobacco species (N. tabacum, N. benthamiana, and N. glutinosa). Both effectors elicit the hypersensitive response (HR) on these tobacco species, although in different manners; AvrA is the major determinant recognized by N. tabacum and N. benthamiana, while PopP1 appears to be the major HR elicitor on N. glutinosa. Only the double inactivation of the avrA and popP1 genes allowed GMI1000 to wilt tobacco plants, thus showing that GMI1000 intrinsically possesses the functions necessary to wilt tobacco plants. A focused analysis on AvrA revealed that the first 58 N-terminal amino acids are sufficient to direct its injection into plant cells. We identified a hypervariable region in avrA, which contains variable numbers of tandem repeats (VNTR), each composed of 12 base pairs. We show that an 18-amino acid region in which the VNTR insertion occurs is an important domain involved in HR elicitation on N. benthamiana. avrA appears to be the target of various DNA insertions or mobile elements that probably allow R. solanacearum to evade the recognition and defense responses of tobacco.
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Affiliation(s)
- Marie Poueymiro
- Laboratoire des Interactions Plantes Micro-organismes, UMR CNRS-INRA 2594/441, Castanet Tolosan, France
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Secreted proteins from Ralstonia solanacearum: a hundred tricks to kill a plant. Curr Opin Microbiol 2009; 12:44-52. [DOI: 10.1016/j.mib.2008.11.008] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 11/26/2008] [Accepted: 11/27/2008] [Indexed: 12/31/2022]
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Y4lO of Rhizobium sp. strain NGR234 is a symbiotic determinant required for symbiosome differentiation. J Bacteriol 2008; 191:735-46. [PMID: 19060155 DOI: 10.1128/jb.01404-08] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Type 3 (T3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial T3 secretion system, affect the nodulation of certain host legumes. The open reading frame y4lO of Rhizobium sp. strain NGR234 encodes a protein with sequence similarities to T3 effectors from pathogenic bacteria (the YopJ effector family). Transcription studies showed that the promoter activity of y4lO depended on the transcriptional activator TtsI. Recombinant Y4lO protein expressed in Escherichia coli did not acetylate two representative mitogen-activated protein kinase kinases (human MKK6 and MKK1 from Medicago truncatula), indicating that YopJ-like proteins differ with respect to their substrate specificities. The y4lO gene was mutated in NGR234 (strain NGROmegay4lO) and in NGR Omega nopL, a mutant that does not produce the T3 effector NopL (strain NGR Omega nopLOmegay4lO). When used as inoculants, the symbiotic properties of the mutants differed. Tephrosia vogelii, Phaseolus vulgaris cv. Yudou No. 1, and Vigna unguiculata cv. Sui Qing Dou Jiao formed pink effective nodules with NGR234 and NGR Omega nopL Omega y4lO. Nodules induced by NGR Omega y4lO were first pink but rapidly turned greenish (ineffective nodules), indicating premature senescence. An ultrastructural analysis of the nodules induced by NGR Omega y4lO revealed abnormal formation of enlarged infection droplets in ineffective nodules, whereas symbiosomes harboring a single bacteroid were frequently observed in effective nodules induced by NGR234 or NGR Omega nopL Omega y4lO. It is concluded that Y4lO is a symbiotic determinant involved in the differentiation of symbiosomes. Y4lO mitigated senescence-inducing effects caused by the T3 effector NopL, suggesting synergistic effects for Y4lO and NopL in nitrogen-fixing nodules.
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