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Geraffi N, Gupta P, Wagner N, Barash I, Pupko T, Sessa G. Comparative sequence analysis of pPATH pathogenicity plasmids in Pantoea agglomerans gall-forming bacteria. FRONTIERS IN PLANT SCIENCE 2023; 14:1198160. [PMID: 37583594 PMCID: PMC10425158 DOI: 10.3389/fpls.2023.1198160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/10/2023] [Indexed: 08/17/2023]
Abstract
Acquisition of the pathogenicity plasmid pPATH that encodes a type III secretion system (T3SS) and effectors (T3Es) has likely led to the transition of a non-pathogenic bacterium into the tumorigenic pathogen Pantoea agglomerans. P. agglomerans pv. gypsophilae (Pag) forms galls on gypsophila (Gypsophila paniculata) and triggers immunity on sugar beet (Beta vulgaris), while P. agglomerans pv. betae (Pab) causes galls on both gypsophila and sugar beet. Draft sequences of the Pag and Pab genomes were previously generated using the MiSeq Illumina technology and used to determine partial T3E inventories of Pab and Pag. Here, we fully assembled the Pab and Pag genomes following sequencing with PacBio technology and carried out a comparative sequence analysis of the Pab and Pag pathogenicity plasmids pPATHpag and pPATHpab. Assembly of Pab and Pag genomes revealed a ~4 Mbp chromosome with a 55% GC content, and three and four plasmids in Pab and Pag, respectively. pPATHpag and pPATHpab share 97% identity within a 74% coverage, and a similar GC content (51%); they are ~156 kb and ~131 kb in size and consist of 198 and 155 coding sequences (CDSs), respectively. In both plasmids, we confirmed the presence of highly similar gene clusters encoding a T3SS, as well as auxin and cytokinins biosynthetic enzymes. Three putative novel T3Es were identified in Pab and one in Pag. Among T3SS-associated proteins encoded by Pag and Pab, we identified two novel chaperons of the ShcV and CesT families that are present in both pathovars with high similarity. We also identified insertion sequences (ISs) and transposons (Tns) that may have contributed to the evolution of the two pathovars. These include seven shared IS elements, and three ISs and two transposons unique to Pab. Finally, comparative sequence analysis revealed plasmid regions and CDSs that are present only in pPATHpab or in pPATHpag. The high similarity and common features of the pPATH plasmids support the hypothesis that the two strains recently evolved into host-specific pathogens.
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Affiliation(s)
- Naama Geraffi
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Priya Gupta
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Isaac Barash
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Guido Sessa
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Jin Y, Zhang W, Cong S, Zhuang QG, Gu YL, Ma YN, Filiatrault MJ, Li JZ, Wei HL. Pseudomonas syringae Type III Secretion Protein HrpP Manipulates Plant Immunity To Promote Infection. Microbiol Spectr 2023; 11:e0514822. [PMID: 37067445 PMCID: PMC10269811 DOI: 10.1128/spectrum.05148-22] [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: 12/14/2022] [Accepted: 03/22/2023] [Indexed: 04/18/2023] Open
Abstract
The bacterial plant pathogen Pseudomonas syringae deploys a type III secretion system (T3SS) to deliver effector proteins into plant cells to facilitate infection, for which many effectors have been characterized for their interactions. However, few T3SS Hrp (hypersensitive response and pathogenicity) proteins from the T3SS secretion apparatus have been studied for their direct interactions with plants. Here, we show that the P. syringae pv. tomato DC3000 T3SS protein HrpP induces host cell death, suppresses pattern-triggered immunity (PTI), and restores the effector translocation ability of the hrpP mutant. The hrpP-transgenic Arabidopsis lines exhibited decreased PTI responses to flg22 and elf18 and enhanced disease susceptibility to P. syringae pv. tomato DC3000. Transcriptome analysis reveals that HrpP sensing activates salicylic acid (SA) signaling while suppressing jasmonic acid (JA) signaling, which correlates with increased SA accumulation and decreased JA biosynthesis. Both yeast two-hybrid and bimolecular fluorescence complementation assays show that HrpP interacts with mitogen-activated protein kinase kinase 2 (MKK2) on the plant membrane and in the nucleus. The HrpP truncation HrpP1-119, rather than HrpP1-101, retains the ability to interact with MKK2 and suppress PTI in plants. In contrast, HrpP1-101 continues to cause cell death and electrolyte leakage. MKK2 silencing compromises SA signaling but has no effect on cell death caused by HrpP. Overall, our work highlights that the P. syringae T3SS protein HrpP facilitates effector translocation and manipulates plant immunity to facilitate bacterial infection. IMPORTANCE The T3SS is required for the virulence of many Gram-negative bacterial pathogens of plants and animals. This study focuses on the sensing and function of the T3SS protein HrpP during plant interactions. Our findings show that HrpP and its N-terminal truncation HrpP1-119 can interact with MKK2, promote effector translocation, and manipulate plant immunity to facilitate bacterial infection, highlighting the P. syringae T3SS component involved in the fine-tuning of plant immunity.
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Affiliation(s)
- Ya Jin
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wei Zhang
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Shen Cong
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qi-Guo Zhuang
- China-New Zealand Belt and Road Joint Laboratory on Kiwifruit, Kiwifruit Breeding and Utilization Key Laboratory of Sichuan Province, Sichuan Provincial Academy of Natural Resource Sciences, Chengdu, China
| | - Yi-Lin Gu
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yi-Nan Ma
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Melanie J. Filiatrault
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
- Emerging Pests and Pathogens Research Unit, Agricultural Research Service, United States Department of Agriculture, Robert W. Holley Center for Agriculture and Health, Ithaca, New York, USA
| | - Jun-Zhou Li
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hai-Lei Wei
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
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Cong S, Li JZ, Xiong ZZ, Wei HL. Diverse interactions of five core type III effectors from Ralstonia solanacearum with plants. J Genet Genomics 2023; 50:341-352. [PMID: 35597445 DOI: 10.1016/j.jgg.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 11/24/2022]
Abstract
Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type III effectors (T3Es) to cause disease. In this study, we isolate a pathogenic R. solanacearum strain named P380 from tomato rhizosphere. Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants. DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression, ROS burst, and callose deposition. RipAE, RipU, and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana. The derivatives RipC1ΔDXDX(T/V) and RipWΔDKXXQ but not RipAEK310R fail to suppress ROS burst. Moreover, RipAEK310R and RipWΔDKXXQ retain the cell death elicitation ability. RipAE and RipW are associated with salicylic acid and jasmonic acid pathways, respectively. RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants. The five core T3Es localize in diverse subcellular organelles of nucleus, plasma membrane, endoplasmic reticulum, and Golgi network. The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N. benthamiana. These results indicate that the core T3Es in R. solanacearum play diverse roles in plant-pathogen interactions.
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Affiliation(s)
- Shen Cong
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jun-Zhou Li
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zheng-Zhong Xiong
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Hai-Lei Wei
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Kvitko BH, Collmer A. Discovery of the Hrp Type III Secretion System in Phytopathogenic Bacteria: How Investigation of Hypersensitive Cell Death in Plants Led to a Novel Protein Injector System and a World of Inter-Organismal Molecular Interactions Within Plant Cells. PHYTOPATHOLOGY 2023; 113:626-636. [PMID: 37099273 DOI: 10.1094/phyto-08-22-0292-kd] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In the early 1960s, Pseudomonas syringae and other host-specific phytopathogenic proteobacteria were discovered to elicit a rapid, resistance-associated death when infiltrated at high inoculum levels into nonhost tobacco leaves. This hypersensitive reaction (or response; HR) was a useful indicator of basic pathogenic ability. Research over the next 20 years failed to identify an elicitor of the HR but revealed that its elicitation required contact between metabolically active bacterial and plant cells. Beginning in the early 1980s, molecular genetic tools were applied to the HR puzzle, revealing the presence in P. syringae of clusters of hrp genes, so named because they are required for the HR and pathogenicity, and of avr genes, so named because their presence confers HR-associated avirulence in resistant cultivars of a host plant species. A series of breakthroughs over the next two decades revealed that (i) hrp gene clusters encode a type III secretion system (T3SS), which injects Avr (now "effector") proteins into plant cells, where their recognition triggers the HR; (ii) T3SSs, which are typically present in pathogenicity islands acquired by horizontal gene transfers, are found in many bacterial pathogens of plants and animals and inject many effector proteins, which are collectively essential for pathogenicity; and (iii) a primary function of phytopathogen effectors is to subvert non-HR defenses resulting from recognition of conserved microbial features presented outside of plant cells. In the 2000s, Hrp system research shifted to extracellular components enabling effector delivery across plant cell walls and plasma membranes, regulation, and tools for studying effectors. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Brian H Kvitko
- Department of Plant Pathology, University of Georgia, 120 Carlton St., Athens, GA 30602
| | - Alan Collmer
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, 334 Plant Science Bldg., Ithaca, NY 14853
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Ishiga T, Sakata N, Usuki G, Nguyen VT, Gomi K, Ishiga Y. Large-Scale Transposon Mutagenesis Reveals Type III Secretion Effector HopR1 Is a Major Virulence Factor in Pseudomonas syringae pv. actinidiae. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010141. [PMID: 36616271 PMCID: PMC9823363 DOI: 10.3390/plants12010141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/11/2022] [Accepted: 12/16/2022] [Indexed: 05/27/2023]
Abstract
Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a serious threat to kiwifruit production worldwide. Four biovars (Psa biovar 1; Psa1, Psa biovar 3; Psa3, Psa biovar 5; Psa5, and Psa biovar 6; Psa6) were reported in Japan, and virulent Psa3 strains spread rapidly to kiwifruit production areas worldwide. Therefore, there is an urgent need to develop critical management strategies for bacterial canker based on dissecting the dynamic interactions between Psa and kiwifruit. To investigate the molecular mechanism of Psa3 infection, we developed a rapid and reliable high-throughput flood-inoculation method using kiwifruit seedlings. Using this inoculation method, we screened 3000 Psa3 transposon insertion mutants and identified 91 reduced virulence mutants and characterized the transposon insertion sites in these mutants. We identified seven type III secretion system mutants, and four type III secretion effectors mutants including hopR1. Mature kiwifruit leaves spray-inoculated with the hopR1 mutant showed significantly reduced virulence compared to Psa3 wild-type, indicating that HopR1 has a critical role in Psa3 virulence. Deletion mutants of hopR1 in Psa1, Psa3, Psa5, and Psa6 revealed that the type III secretion effector HopR1 is a major virulence factor in these biovars. Moreover, hopR1 mutants of Psa3 failed to reopen stomata on kiwifruit leaves, suggesting that HopR1 facilitates Psa entry through stomata into plants. Furthermore, defense related genes were highly expressed in kiwifruit plants inoculated with hopR1 mutant compared to Psa wild-type, indicating that HopR1 suppresses defense-related genes of kiwifruit. These results suggest that HopR1 universally contributes to virulence in all Psa biovars by overcoming not only stomatal-based defense, but also apoplastic defense.
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Affiliation(s)
- Takako Ishiga
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
| | - Nanami Sakata
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
| | - Giyu Usuki
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
| | - Viet Tru Nguyen
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
- Western Highlands Agriculture and Forestry Science Institute, 53 Nguyen Luong Bang Street, Buon Ma Thuot City 630000, Vietnam
| | - Kenji Gomi
- Faculty of Agriculture, Kagawa University, Miki 761-0795, Kagawa, Japan
| | - Yasuhiro Ishiga
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Ibaraki, Japan
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Olawole OI, Gleason ML, Beattie GA. Expression and Functional Analysis of the Type III Secretion System Effector Repertoire of the Xylem Pathogen Erwinia tracheiphila on Cucurbits. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:768-778. [PMID: 35471035 DOI: 10.1094/mpmi-01-22-0002-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The predicted repertoire of type III secretion system effectors (T3SEs) in Erwinia tracheiphila, causal agent of cucurbit bacterial wilt, is much larger than in xylem pathogens in the closely related genera Erwinia and Pantoea. The genomes of strains BHKY and SCR3, which represent distinct E. tracheiphila clades, encode at least 6 clade-specific and 12 shared T3SEs. The strains expressed the majority of the T3SE genes examined in planta. Among the shared T3SE genes, eop1 was expressed most highly in both strains in squash (Cucurbita pepo) and muskmelon (Cucumis melo) but the clade-specific gene avrRpm2 was expressed 40- to 900-fold more than eop1 in BHKY. The T3SEs AvrRpm2, Eop1, SrfC, and DspE contributed to BHKY virulence on squash and muskmelon, as shown using combinatorial mutants involving six T3SEs, whereas OspG and AvrB4 contributed to BHKY virulence only on muskmelon, demonstrating host-specific virulence functions. Moreover, Eop1 was functionally redundant with AvrRpm2, SrfC, OspG, and AvrB4 in BHKY, and BHKY mutants lacking up to five effector genes showed similar virulence to mutants lacking only two genes. The T3SEs OspG, AvrB4, and DspE contributed additively to SCR3 virulence on muskmelon and were not functionally redundant with Eop1. Rather, loss of eop1 and avrB4 restored wild-type virulence to the avrB4 mutant, suggesting that Eop1 suppresses a functionally redundant effector in SCR3. These results highlight functional differences in effector inventories between two E. tracheiphila clades, provide the first evidence of OspG as a phytopathogen effector, and suggest that Eop1 may be a metaeffector influencing virulence. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Olakunle I Olawole
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011-1101, U.S.A
| | - Mark L Gleason
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011-1101, U.S.A
| | - Gwyn A Beattie
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011-1101, U.S.A
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Song GC, Jeon J, Choi HK, Sim H, Kim S, Ryu C. Bacterial type III effector-induced plant C8 volatiles elicit antibacterial immunity in heterospecific neighbouring plants via airborne signalling. PLANT, CELL & ENVIRONMENT 2022; 45:236-247. [PMID: 34708407 PMCID: PMC9298316 DOI: 10.1111/pce.14209] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/08/2021] [Accepted: 10/15/2021] [Indexed: 05/10/2023]
Abstract
Upon sensing attack by pathogens and insect herbivores, plants release complex mixtures of volatile compounds. Here, we show that the infection of lima bean (Phaseolus lunatus L.) plants with the non-host bacterial pathogen Pseudomonas syringae pv. tomato led to the production of microbe-induced plant volatiles (MIPVs). Surprisingly, the bacterial type III secretion system, which injects effector proteins directly into the plant cytosol to subvert host functions, was found to prime both intra- and inter-specific defense responses in neighbouring wild tobacco (Nicotiana benthamiana) plants. Screening of each of 16 effectors using the Pseudomonas fluorescens effector-to-host analyser revealed that an effector, HopP1, was responsible for immune activation in receiver tobacco plants. Further study demonstrated that 1-octen-3-ol, 3-octanone and 3-octanol are novel MIPVs emitted by the lima bean plant in a HopP1-dependent manner. Exposure to synthetic 1-octen-3-ol activated immunity in tobacco plants against a virulent pathogen Pseudomonas syringae pv. tabaci. Our results show for the first time that a bacterial type III effector can trigger the emission of C8 plant volatiles that mediate defense priming via plant-plant interactions. These results provide novel insights into the role of airborne chemicals in bacterial pathogen-induced inter-specific plant-plant interactions.
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Affiliation(s)
- Geun Cheol Song
- Molecular Phytobacteriology LaboratoryInfectious Disease Research Center, KRIBBDaejeonSouth Korea
| | - Je‐Seung Jeon
- Molecular Phytobacteriology LaboratoryInfectious Disease Research Center, KRIBBDaejeonSouth Korea
| | - Hye Kyung Choi
- Molecular Phytobacteriology LaboratoryInfectious Disease Research Center, KRIBBDaejeonSouth Korea
| | - Hee‐Jung Sim
- Environmental Chemistry Research GroupKorea Institute of Toxicology (KIT)JinjuSouth Korea
| | - Sang‐Gyu Kim
- Department of Biological SciencesKorea Advanced Institute of Science and TechnologyDaejeonSouth Korea
| | - Choong‐Min Ryu
- Molecular Phytobacteriology LaboratoryInfectious Disease Research Center, KRIBBDaejeonSouth Korea
- Biosystems and Bioengineering ProgramUniversity of Science and Technology (UST)DaejeonSouth Korea
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Cai Z, Wang Z, Yue C, Sun A, Shen Y. Efficient expression and purification of soluble Harpin Ea protein by translation initiation region codon optimization. Protein Expr Purif 2021; 188:105970. [PMID: 34500070 DOI: 10.1016/j.pep.2021.105970] [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: 06/04/2021] [Revised: 08/31/2021] [Accepted: 09/05/2021] [Indexed: 11/19/2022]
Abstract
HarpinEa protein can stimulate plants to produce defense responses to resist the attack of pathogens, improve plant immune resistance, and promote plant growth. This has extremely high application value in agriculture. To efficiently express soluble HarpinEa protein, in this study, we expressed HarpinEa protein with a 6× His-tag in Escherichia coli BL21 (DE3). Because of the low level of expression of HarpinEa protein in E. coli, three rounds of synonymous codon optimization were performed on the +53 bp of the translation initiation region (TIR) of HarpinEa. Soluble HarpinEa protein after optimization accounted for 50.3% of the total soluble cellular protein expressed. After purification using a Ni Bestarose Fast Flow column, the purity of HarpinEa protein exceeded 95%, and the yield reached 227.5 mg/L of culture medium. The purified HarpinEa protein was sensitive to proteases and exhibited thermal stability. It triggered visible hypersensitive responses after being injected into tobacco leaves for 48 h. Plants treated with HarpinEa showed obvious growth-promoting and resistance-improving performance. Thus, the use of TIR synonymous codon optimization successfully achieved the economical, efficient, and soluble production of HarpinEa protein.
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Affiliation(s)
- Zengying Cai
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Zhong Wang
- Shandong Shennong Ecological Technology Research Institute Co., Ltd., Shanghai Branch, Shanghai, 201114, China.
| | - Cheng Yue
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Aiyou Sun
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Yaling Shen
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
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Chen X, Ma J, Wang X, Lu K, Liu Y, Zhang L, Peng J, Chen L, Yang M, Li Y, Cheng Z, Xiao S, Yu J, Zou S, Liang Y, Zhang M, Yang Y, Ding X, Dong H. Functional modulation of an aquaporin to intensify photosynthesis and abrogate bacterial virulence in rice. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:330-346. [PMID: 34273211 DOI: 10.1111/tpj.15427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/02/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Plant aquaporins are a recently noted biological resource with a great potential to improve crop growth and defense traits. Here, we report the functional modulation of the rice (Oryza sativa) aquaporin OsPIP1;3 to enhance rice photosynthesis and grain production and to control bacterial blight and leaf streak, the most devastating worldwide bacterial diseases in the crop. We characterize OsPIP1;3 as a physiologically relevant CO2 -transporting facilitator, which supports 30% of rice photosynthesis on average. This role is nullified by interaction of OsPIP1;3 with the bacterial protein Hpa1, an essential component of the Type III translocon that supports translocation of the bacterial Type III effectors PthXo1 and TALi into rice cells to induce leaf blight and streak, respectively. Hpa1 binding shifts OsPIP1;3 from CO2 transport to effector translocation, aggravates bacterial virulence, and blocks rice photosynthesis. On the contrary, the external application of isolated Hpa1 to rice plants effectively prevents OsPIP1;3 from interaction with Hpa1 secreted by the bacteria that are infecting the plants. Blockage of the OsPIP1;3-Hpa1 interaction reverts OsPIP1;3 from effector translocation to CO2 transport, abrogates bacterial virulence, and meanwhile induces defense responses in rice. These beneficial effects can combine to enhance photosynthesis by 29-30%, reduce bacterial disease by 58-75%, and increase grain yield by 11-34% in different rice varieties investigated in small-scale field trials conducted during the past years. Our results suggest that crop productivity and immunity can be coordinated by modulating the physiological and pathological functions of a single aquaporin to break the growth-defense tradeoff barrier.
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Affiliation(s)
- Xiaochen Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Jinbiao Ma
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Xuan Wang
- Department of Biology, Institute of Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu Province, China
| | - Kai Lu
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
| | - Yan Liu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Liyuan Zhang
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
- State Key Laboratory of Crop Biology, Taian, Shandong Province, China
| | - Jinfeng Peng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Lei Chen
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
- State Key Laboratory of Crop Biology, Taian, Shandong Province, China
| | - Minkai Yang
- Department of Biology, Institute of Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu Province, China
| | - Yang Li
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
- State Key Laboratory of Crop Biology, Taian, Shandong Province, China
| | - Zaiquan Cheng
- Biotechnology and Genetic Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan Province, China
| | - Suqin Xiao
- Biotechnology and Genetic Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan Province, China
| | - Jinfeng Yu
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
| | - Shenshen Zou
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
- State Key Laboratory of Crop Biology, Taian, Shandong Province, China
| | - Yuancun Liang
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
| | - Meixiang Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Yonghua Yang
- Department of Biology, Institute of Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu Province, China
| | - Xinhua Ding
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
- State Key Laboratory of Crop Biology, Taian, Shandong Province, China
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Kharadi RR, Schachterle JK, Yuan X, Castiblanco LF, Peng J, Slack SM, Zeng Q, Sundin GW. Genetic Dissection of the Erwinia amylovora Disease Cycle. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:191-212. [PMID: 33945696 DOI: 10.1146/annurev-phyto-020620-095540] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fire blight, caused by the bacterial phytopathogen Erwinia amylovora, is an economically important and mechanistically complex disease that affects apple and pear production in most geographic production hubs worldwide. We compile, assess, and present a genetic outlook on the progression of an E. amylovora infection in the host. We discuss the key aspects of type III secretion-mediated infection and systemic movement, biofilm formation in xylem, and pathogen dispersal via ooze droplets, a concentrated suspension of bacteria and exopolysaccharide components. We present an overall outlook on the genetic elements contributing to E. amylovora pathogenesis, including an exploration of the impact of floral microbiomes on E. amylovora colonization, and summarize the current knowledge of host responses to an incursion and how this response stimulates further infection and systemic spread. We hope to facilitate the identification of new, unexplored areas of research in this pathosystem that can help identify evolutionarily susceptible genetic targets to ultimately aid in the design of sustainable strategies for fire blight disease mitigation.
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Affiliation(s)
- Roshni R Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Jeffrey K Schachterle
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
- Floral and Nursery Plants Research Unit, US National Arboretum, USDA-ARS, Beltsville, Maryland 20705, USA
| | - Xiaochen Yuan
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Luisa F Castiblanco
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Jingyu Peng
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Suzanne M Slack
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Quan Zeng
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, USA
| | - George W Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
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11
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Yuan X, Hulin MT, Sundin GW. Effectors, chaperones, and harpins of the Type III secretion system in the fire blight pathogen Erwinia amylovora: a review. JOURNAL OF PLANT PATHOLOGY 2021; 103:25-39. [PMID: 0 DOI: 10.1007/s42161-020-00623-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/23/2020] [Indexed: 05/20/2023]
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12
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Kang JE, Jeon BJ, Park MY, Kim BS. Inhibitory Activity of Sedum middendorffianum-Derived 4-Hydroxybenzoic Acid and Vanillic Acid on the Type III Secretion System of Pseudomonas syringae pv. tomato DC3000. THE PLANT PATHOLOGY JOURNAL 2020; 36:608-617. [PMID: 33312096 PMCID: PMC7721535 DOI: 10.5423/ppj.oa.08.2020.0162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/24/2020] [Accepted: 09/28/2020] [Indexed: 05/12/2023]
Abstract
The type III secretion system (T3SS) is a key virulence determinant in the infection process of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Pathogen constructs a type III apparatus to translocate effector proteins into host cells, which have various roles in pathogenesis. 4-Hydroxybenozic acid and vanillic acid were identified from root extract of Sedum middendorffianum to have inhibitory effect on promoter activity of hrpA gene encoding the structural protein of the T3SS apparatus. The phenolic acids at 2.5 mM significantly suppressed the expression of hopP1, hrpA, and hrpL in the hrp/hrc gene cluster without growth retardation of Pst DC3000. Auto-agglutination of Pst DC3000 cells, which is induced by T3SS, was impaired by the treatment of 4-hydroxybenzoic acid and vanillic acid. Additionally, 2.5 mM of each two phenolic acids attenuated disease symptoms including chlorosis surrounding bacterial specks on tomato leaves. Our results suggest that 4-hydroxybenzoic acid and vanillic acid are potential anti-virulence agents suppressing T3SS of Pst DC3000 for the control of bacterial diseases.
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Affiliation(s)
- Ji Eun Kang
- Department of Biosystems and Biotechnology, Korea University Graduate School, Seoul 0284, Korea
| | - Byeong Jun Jeon
- Department of Biosystems and Biotechnology, Korea University Graduate School, Seoul 0284, Korea
| | - Min Young Park
- Department of Biosystems and Biotechnology, Korea University Graduate School, Seoul 0284, Korea
| | - Beom Seok Kim
- Department of Biosystems and Biotechnology, Korea University Graduate School, Seoul 0284, Korea
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 0841, Korea
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13
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Liu Y, Zhou X, Liu W, Miao W. The stability of the coiled-coil structure near to N-terminus influence the heat resistance of harpin proteins from Xanthomonas. BMC Microbiol 2020; 20:344. [PMID: 33183263 PMCID: PMC7663895 DOI: 10.1186/s12866-020-02029-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/01/2020] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Heat resistance is a common characteristic of harpins, a class of proteins found in Gram-negative bacteria, which may be related to the stability of coiled-coil (CC) structure. The CC structure is a ubiquitous protein folding and assembly motif made of α-helices wrapping around each other forming a supercoil. Specifically, whether the stability of the CC structure near to N-terminus of four selected harpin proteins from Xanthomonas (hereafter referred to as Hpa1) would influence their characteristics of heat resistance was investigated. We used bioinformatics approach to predict the structure of Hpa1, used the performance of hypersensitive response (HR)-induction activity of Hpa1 and circular dichroism (CD) spectral analyses to detect the relationship between the stability of the CC structure of Hpa1 and heat resistance. RESULTS Each of four-selected Hpa1 has two α-helical regions with one in their N-terminus that could form CC structure, and the other in their C-terminus that could not. And the important amino acid residues involved in the CC motifs are located on helices present on the surface of these proteins, indicating they may engage in the formation of oligo mericaggregates, which may be responsible for HR elicitation by harpins and their high thermal stability. Increased or decreased the probability of forming a CC could either induce a stronger HR response or eliminate the ability to induce HR in tobacco after high temperature treatment. In addition, although the four Hpa1 mutants had little effect on the induction of HR by Hpa1, its thermal stability was significantly decreased. The α-helical content increased with increasing temperature, and the secondary structures of Hpa1 became almost entirely α-helices when the temperature reached 200 °C. Moreover, the stability of the CC structure near to N-terminus was found to be positively correlated with the heat resistance of Hpa1. CONCLUSIONS The stability of the CC structure might sever as an inner drive for mediating the heat resistance of harpin proteins. Our results offer a new insight into the interpretation of the mechanism involved in the heat resistance of harpin protein and provide a theoretical basis for further harpin function investigations and structure modifications.
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Affiliation(s)
- Yue Liu
- College of Plant Protection, Hainan University, Haikou, Hainan Province, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, Hainan Province, China
| | - Xiaoyun Zhou
- College of Plant Protection, Hainan University, Haikou, Hainan Province, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, Hainan Province, China
| | - Wenbo Liu
- College of Plant Protection, Hainan University, Haikou, Hainan Province, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, Hainan Province, China
| | - Weiguo Miao
- College of Plant Protection, Hainan University, Haikou, Hainan Province, China.
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou, Hainan Province, China.
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14
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Jayaraman J, Yoon M, Applegate ER, Stroud EA, Templeton MD. AvrE1 and HopR1 from Pseudomonas syringae pv. actinidiae are additively required for full virulence on kiwifruit. MOLECULAR PLANT PATHOLOGY 2020; 21:1467-1480. [PMID: 32969167 PMCID: PMC7548996 DOI: 10.1111/mpp.12989] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/14/2020] [Accepted: 08/14/2020] [Indexed: 06/01/2023]
Abstract
Pseudomonas syringae pv. actinidiae ICMP 18884 biovar 3 (Psa3) produces necrotic lesions during infection of its kiwifruit host. Bacterial growth in planta and lesion formation are dependent upon a functional type III secretion system (T3S), which translocates multiple effector proteins into host cells. Associated with the T3S locus is the conserved effector locus (CEL), which has been characterized and shown to be essential for the full virulence in other P. syringae pathovars. Two effectors at the CEL, hopM1 and avrE1, as well as an avrE1-related non-CEL effector, hopR1, have been shown to be redundant in the model pathogen P. syringae pv. tomato DC3000 (Pto), a close relative of Psa. However, it is not known whether CEL-related effectors are required for Psa pathogenicity. The Psa3 allele of hopM1, and its associated chaperone, shcM, have diverged significantly from their orthologs in Pto. Furthermore, the CEL effector hopAA1-1, as well as a related non-CEL effector, hopAA1-2, have both been pseudogenized. We have shown that HopM1 does not contribute to Psa3 virulence due to a truncation in shcM, a truncation conserved in the Psa lineage, probably due to the need to evade HopM1-triggered immunity in kiwifruit. We characterized the virulence contribution of CEL and related effectors in Psa3 and found that only avrE1 and hopR1, additively, are required for in planta growth and lesion production. This is unlike the redundancy described for these effectors in Pto and indicates that these two Psa3 genes are key determinants essential for kiwifruit bacterial canker disease.
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Affiliation(s)
- Jay Jayaraman
- The New Zealand Institute for Plant and Food Research LimitedAucklandNew Zealand
- Bio‐Protection Research CentreLincolnNew Zealand
| | - Minsoo Yoon
- The New Zealand Institute for Plant and Food Research LimitedAucklandNew Zealand
| | - Emma R. Applegate
- The New Zealand Institute for Plant and Food Research LimitedAucklandNew Zealand
- School of Biological SciencesUniversity of AucklandAucklandNew Zealand
- Present address:
AgResearch Ltd., Grasslands Research CentrePalmerston NorthNew Zealand
| | - Erin A. Stroud
- The New Zealand Institute for Plant and Food Research LimitedAucklandNew Zealand
- School of Biological SciencesUniversity of AucklandAucklandNew Zealand
| | - Matthew D. Templeton
- The New Zealand Institute for Plant and Food Research LimitedAucklandNew Zealand
- Bio‐Protection Research CentreLincolnNew Zealand
- School of Biological SciencesUniversity of AucklandAucklandNew Zealand
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15
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Phytopathogen Effectors Use Multiple Mechanisms to Manipulate Plant Autophagy. Cell Host Microbe 2020; 28:558-571.e6. [PMID: 32810441 DOI: 10.1016/j.chom.2020.07.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/23/2020] [Accepted: 07/20/2020] [Indexed: 01/10/2023]
Abstract
Autophagy is a central part of immunity and hence is a key target of pathogens. However, the precise molecular mechanisms by which plant pathogens manipulate autophagy remain elusive. We identify a network of 88 interactions between 184 effectors from bacterial, fungal, oomycete, and nematode pathogens with 25 Arabidopsis autophagy (ATG) proteins. Notably, Pseudomonas syringae pv tomato (Pto) bacterial effectors HrpZ1, HopF3, and AvrPtoB employ distinct molecular strategies to modulate autophagy. Calcium-dependent HrpZ1 oligomerization targets ATG4b-mediated cleavage of ATG8 to enhance autophagy, while HopF3 also targets ATG8 but suppresses autophagy, with both effectors promoting infection. AvrPtoB affects ATG1 kinase phosphorylation and enhances bacterial virulence. Since pathogens inject limited numbers of effectors into hosts, our findings establish autophagy as a key target during infection. Additionally, as autophagy is enhanced and inhibited by these effectors, autophagy likely has different functions throughout infection and, thus, must be temporally and precisely regulated for successful infection.
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16
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Mo X, Zhang L, Liu Y, Wang X, Bai J, Lu K, Zou S, Dong H, Chen L. Three Proteins (Hpa2, HrpF and XopN) Are Concomitant Type III Translocators in Bacterial Blight Pathogen of Rice. Front Microbiol 2020; 11:1601. [PMID: 32793141 PMCID: PMC7390958 DOI: 10.3389/fmicb.2020.01601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/18/2020] [Indexed: 12/31/2022] Open
Abstract
Type III (T3) proteic effectors occupy most of the virulence determinants in eukaryote-pathogenic Gram-negative bacteria. During infection, bacteria may deploy a nanomachinery called translocon to deliver T3 effectors into host cells, wherein the effectors fulfill their pathological functions. T3 translocon is hypothetically assembled by bacterial translocators, which have been identified as one hydrophilic and two hydrophobic proteins in animal-pathogenic bacteria but remain unclear in plant pathogens. Now we characterize Hpa2, HrpF, and XopN proteins as concomitant T3 translocators in rice bacterial blight pathogen by analyzing pathological consequences of single, double, and triple gene knockout or genetic complementation. Based on these genetic analyses, Hpa2, HrpF, and XopN accordingly contribute to 46.9, 60.3, and 69.8% proportions of bacterial virulence on a susceptible rice variety. Virulence performances of Hpa2, HrpF, and XopN were attributed to their functions in essentially mediating from-bacteria-into-rice-cell translocation of PthXo1, the bacterial T3 effector characteristic of transcription factors targeting plant genes. On average, 61, 62, and 71% of PthXo1 translocation are provided correspondingly by Hpa2, HrpF, and XopN, while they cooperate to support PthXo1 translocation at a greater-than-95% extent. As a result, rice disease-susceptibility gene SWEET11, which is the regulatory target of PthXo1, is activated to confer bacterial virulence and induce the leaf blight disease in rice. Furthermore, the three translocators also undergo translocation, but only XopN is highly translocated to suppress rice defense responses, suggesting that different components of a T3 translocon deploy distinct virulence mechanisms in addition to the common function in mediating bacterial effector translocation.
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Affiliation(s)
- Xuyan Mo
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Liyuan Zhang
- College of Plant Protection, Shandong Agricultural University, Tai’an, China
- Crop Molecular Biology Research Group, State Key Laboratory of Crop Biology, Tai’an, China
| | - Yan Liu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Xuan Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jiaqi Bai
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Kai Lu
- College of Plant Protection, Shandong Agricultural University, Tai’an, China
| | - Shenshen Zou
- College of Plant Protection, Shandong Agricultural University, Tai’an, China
- Crop Molecular Biology Research Group, State Key Laboratory of Crop Biology, Tai’an, China
| | - Hansong Dong
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- College of Plant Protection, Shandong Agricultural University, Tai’an, China
- Crop Molecular Biology Research Group, State Key Laboratory of Crop Biology, Tai’an, China
| | - Lei Chen
- College of Plant Protection, Shandong Agricultural University, Tai’an, China
- Crop Molecular Biology Research Group, State Key Laboratory of Crop Biology, Tai’an, China
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17
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Nobori T, Wang Y, Wu J, Stolze SC, Tsuda Y, Finkemeier I, Nakagami H, Tsuda K. Multidimensional gene regulatory landscape of a bacterial pathogen in plants. NATURE PLANTS 2020; 6:883-896. [PMID: 32541952 DOI: 10.1038/s41477-020-0690-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/08/2020] [Indexed: 05/25/2023]
Abstract
Understanding the gene regulation of plant pathogens is crucial for pest control and thus global food security. An integrated understanding of bacterial gene regulation in the host is dependent on multi-omic datasets, but these are largely lacking. Here, we simultaneously characterized the transcriptome and proteome of a bacterial pathogen in plants. We found a number of bacterial processes affected by plant immunity at the transcriptome and proteome levels. For instance, salicylic acid-mediated plant immunity suppressed the accumulation of proteins comprising the tip component of the bacterial type III secretion system. Interestingly, there were instances of concordant and discordant regulation of bacterial messenger RNAs and proteins. Gene co-expression analysis uncovered previously unknown gene regulatory modules underlying virulence. This study provides molecular insights into the multiple layers of gene regulation that contribute to bacterial growth in planta, and elucidates the role of plant immunity in affecting pathogen responses.
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Affiliation(s)
- Tatsuya Nobori
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Yiming Wang
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- College of Plant Protection, Nanjing Agriculture University, Nanjing, China
| | - Jingni Wu
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Sara Christina Stolze
- Protein Mass Spectrometry Group, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Yayoi Tsuda
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Iris Finkemeier
- Protein Mass Spectrometry Group, Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Institute of Plant Biology and Biotechnology, University of Muenster, Münster, Germany
| | - Hirofumi Nakagami
- Protein Mass Spectrometry Group, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Kenichi Tsuda
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
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18
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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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19
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Zhang B, Zhang Y, Liang F, Ma Y, Wu X. An Extract Produced by Bacillus sp. BR3 Influences the Function of the GacS/GacA Two-Component System in Pseudomonas syringae pv. tomato DC3000. Front Microbiol 2019; 10:2005. [PMID: 31572307 PMCID: PMC6749012 DOI: 10.3389/fmicb.2019.02005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/15/2019] [Indexed: 12/03/2022] Open
Abstract
The GacS/GacA two-component system is essential for virulence in many plant pathogenic bacteria, and thus represents a promising anti-virulence target. In the present study, we isolated and screened rhizobacteria that were capable of inhibiting the expression of the gacS gene in the phytopathogenic bacterium Pseudomonas syringae pv. tomato (Pto) DC3000. One candidate inhibitor bacterium, BR3 was obtained and identified as a Bacillus sp. strain based on 16s rRNA gene sequence analysis. Besides the gacS gene, the GacA-dependent small RNA genes rsmZ and rsmY were repressed transcriptionally when DC3000 was treated with an extract from strain BR3. Importantly, the extract also influenced bacterial motility, the expression of type three secretion system effector AvrPto, and the plant hypersensitive response triggered by strain DC3000. The results suggested that the extract from strain BR3 might offer an alternative method to control bacterial diseases in plants by targeting the GacS/GacA system.
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Affiliation(s)
- Bo Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Yang Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Fei Liang
- College of Agriculture, Guangxi University, Nanning, China
| | - Yinan Ma
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning, China
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20
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Bian H, Zhang L, Chen L, Wang W, Ji H, Dong H. Real-time monitoring of translocation of selected type-III effectors from Xanthomonas oryzae pv. oryzae into rice cells. J Biosci 2019; 44:82. [PMID: 31502560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Type-III (T3) effectors PthXo1 and AvrXa10 of Xanthomonas oryzae pv. oryzae are translocated into rice cells to induce virulence and avirulence on susceptible- and resistant-rice varieties Nipponbare and IRBB10, respectively. The translocation needs the bacterial T3 translocator Hpa1 and rice Oryza sativa plasma membrane protein OsPIP1;3. Here, we employed the beta-lactamase (BlaM) reporter system to observe PthXo1 and AvrXa10 translocation. The system was established to monitor effectors of animal-pathogenic bacteria by quantifying the BlaM hydrolysis product [P] and fluorescence resonance energy transfer (FRET) of the substrate. The feasibility of the BlaM reporter in rice protoplasts was evaluated by three criteria. The first criterion indicated differences between both [P] and FRET levels among wild types and OsPIP1;3-overexpressing and OsPIP1;3-silenced lines of both Nipponbare and IRBB10. The second criterion indicated differences between [P] and FRET levels in the presence and absence of Hpa1. The last criterion elucidated the coincidence of PthXo1 translocation with induced expression of the PthXo1 target gene in protoplasts of Nipponbare and the coincidence of AvrXa10 translocation with induced expression of the AvrXa10 target gene in protoplasts of IRBB10. These results provide an experimental avenue for real-time monitoring of bacterial T3 effector translocation into plant cells with a pathological consequence.
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Affiliation(s)
- Huijie Bian
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China
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21
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Bian H, Zhang L, Chen L, Wang W, Ji H, Dong H. Real-time monitoring of translocation of selected type-III effectors from Xanthomonas oryzae pv. oryzae into rice cells. J Biosci 2019. [DOI: 10.1007/s12038-019-9916-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Li P, Zhang L, Mo X, Ji H, Bian H, Hu Y, Majid T, Long J, Pang H, Tao Y, Ma J, Dong H. Rice aquaporin PIP1;3 and harpin Hpa1 of bacterial blight pathogen cooperate in a type III effector translocation. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3057-3073. [PMID: 30921464 PMCID: PMC6598099 DOI: 10.1093/jxb/erz130] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 03/12/2019] [Indexed: 05/20/2023]
Abstract
Varieties of Gram-negative bacterial pathogens infect their eukaryotic hosts by deploying the type III translocon to deliver effector proteins into the cytosol of eukaryotic cells in which effectors execute their pathological functions. The translocon is hypothetically assembled by bacterial translocators in association with the assumed receptors situated on eukaryotic plasma membranes. This hypothesis is partially verified in the present study with genetic, biochemical, and pathological evidence for the role of a rice aquaporin, plasma membrane intrinsic protein PIP1;3, in the cytosolic import of the transcription activator-like effector PthXo1 from the bacterial blight pathogen. PIP1;3 interacts with the bacterial translocator Hpa1 at rice plasma membranes to control PthXo1 translocation from cells of a well-characterized strain of the bacterial blight pathogen into the cytosol of cells of a susceptible rice variety. An extracellular loop sequence of PIP1;3 and the α-helix motif of Hpa1 determine both the molecular interaction and its consequences with respect to the effector translocation and the bacterial virulence on the susceptible rice variety. Overall, these results provide multiple experimental avenues to support the hypothesis that interactions between bacterial translocators and their interactors at the target membrane are essential for bacterial effector translocation.
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Affiliation(s)
- Ping Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Liyuan Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
- Department of Plant Pathology, Shandong Agricultural University, Taian, Shandong Province, China
| | - Xuyan Mo
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Hongtao Ji
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
- Department of Biology, Jiangsu Formal University, Xuzhou, Jiangsu Province, China
| | - Huijie Bian
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Yiqun Hu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Taha Majid
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Juying Long
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Hao Pang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Yuan Tao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Jinbiao Ma
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu Province, China
- Department of Plant Pathology, Shandong Agricultural University, Taian, Shandong Province, China
- Correspondence:
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Zhang L, Chen L, Dong H. Plant Aquaporins in Infection by and Immunity Against Pathogens - A Critical Review. FRONTIERS IN PLANT SCIENCE 2019; 10:632. [PMID: 31191567 PMCID: PMC6546722 DOI: 10.3389/fpls.2019.00632] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/26/2019] [Indexed: 05/18/2023]
Abstract
Plant aquaporins (AQPs) of the plasma membrane intrinsic protein (PIP) family face constant risk of hijack by pathogens aiming to infect plants. PIPs can also be involved in plant immunity against infection. This review will utilize two case studies to discuss biochemical and structural mechanisms that govern the functions of PIPs in the regulation of plant infection and immunity. The first example concerns the interaction between rice Oryza sativa and the bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). To infect rice, Xoo uses the type III (T3) secretion system to secrete the proteic translocator Hpa1, and Hpa1 subsequently mediates the translocation of T3 effectors secreted by this system. Once shifted from bacteria into rice cells, effectors exert virulent or avirulent effects depending on the susceptibility of the rice varieties. The translocator function of Hpa1 requires cooperation with OsPIP1;3, the rice interactor of Hpa1. This role of OsPIP1;3 is related to regulatory models of effector translocation. The regulatory models have been proposed as, translocon-dependent delivery, translocon-independent pore formation, and effector endocytosis with membrane protein/lipid trafficking. The second case study includes the interaction of Hpa1 with the H2O2 transport channel AtPIP1;4, and the associated consequence for H2O2 signal transduction of immunity pathways in Arabidopsis thaliana, a non-host of Xoo. H2O2 is generated in the apoplast upon induction by a pathogen or microbial pattern. H2O2 from this source translocates quickly into Arabidopsis cells, where it interacts with pathways of intracellular immunity to confer plant resistance against diseases. To expedite H2O2 transport, AtPIP1;4 must adopt a specific conformation in a number of ways, including channel width extension through amino acid interactions and selectivity for H2O2 through amino acid protonation and tautomeric reactions. Both topics will reference relevant studies, conducted on other organisms and AQPs, to highlight possible mechanisms of T3 effector translocation currently under debate, and highlight the structural basis of AtPIP1;4 in H2O2 transport facilitated by gating and trafficking regulation.
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Affiliation(s)
- Liyuan Zhang
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
| | - Lei Chen
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
| | - Hansong Dong
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
- Plant Immunity Laboratory, Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
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Czobor Á, Hajdinák P, Németh B, Piros B, Németh Á, Szarka A. Comparison of the response of alternative oxidase and uncoupling proteins to bacterial elicitor induced oxidative burst. PLoS One 2019; 14:e0210592. [PMID: 30629714 PMCID: PMC6328269 DOI: 10.1371/journal.pone.0210592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/25/2018] [Indexed: 12/03/2022] Open
Abstract
Plant UCPs are proved to take part in the fine-tuning of mitochondrial ROS generation. It has emerged that mitochondrion can be an important early source of intracellular ROS during plant-pathogen interaction thus plant UCPs must also play key role in this redox fine-tuning during the early phase of plant-pathogen interaction. On the contrary of this well-established assumption, the expression of plant UCPs and their activity has not been investigated in elicitor induced oxidative burst. Thus, the level of plant UCPs both at RNA and protein level and their activity was investigated and compared to AOX as a reference in Arabidopsis thaliana cells due to bacterial harpin treatments. Similar to the expression and activity of AOX, the transcript level of UCP4, UCP5 and the UCP activity increased due to harpin treatment and the consequential oxidative burst. The expression of UCP4 and UCP5 elevated 15-18-fold after 1 h of treatment, then the activity of UCP reached its maximal value at 4h of treatment. The quite rapid activation of UCP due to harpin treatment gives another possibility to fine tune the redox balance of plant cell, furthermore explains the earlier observed rapid decrease of mitochondrial membrane potential and consequent decrease of ATP synthesis after harpin treatment.
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Affiliation(s)
- Ádám Czobor
- Department of Applied Biotechnology and Food Science, Laboratory of Biochemistry and Molecular Biology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Péter Hajdinák
- Department of Applied Biotechnology and Food Science, Laboratory of Biochemistry and Molecular Biology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Bence Németh
- Department of Applied Biotechnology and Food Science, Laboratory of Biochemistry and Molecular Biology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Borbála Piros
- Department of Applied Biotechnology and Food Science, Laboratory of Biochemistry and Molecular Biology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Áron Németh
- Department of Applied Biotechnology and Food Science, Fermentation Pilot Plant Laboratory, Budapest University of Technology and Economics, Budapest, Hungary
| | - András Szarka
- Department of Applied Biotechnology and Food Science, Laboratory of Biochemistry and Molecular Biology, Budapest University of Technology and Economics, Budapest, Hungary
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Hu Y, Zhang L, Wang X, Sun F, Kong X, Dong H, Xu H. Two virulent sRNAs identified by genomic sequencing target the type III secretion system in rice bacterial blight pathogen. BMC PLANT BIOLOGY 2018; 18:237. [PMID: 30326834 PMCID: PMC6192180 DOI: 10.1186/s12870-018-1470-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 10/05/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND Small non-coding RNA (sRNA) short sequences regulate various biological processes in all organisms, including bacteria that are animal or plant pathogens. Virulent or pathogenicity-associated sRNAs have been increasingly elucidated in animal pathogens but little is known about similar category of sRNAs in plant-pathogenic bacteria. This is particularly true regarding rice bacterial blight pathogen Xanthomonas oryzae pathovar oryzae (Xoo) as studies on the virulent role of Xoo sRNAs is very limited at present. RESULTS The number and genomic distribution of sRNAs in Xoo were determined by bioinformatics analysis based on high throughput sequencing (sRNA-Seq) of the bacterial cultures from virulence-inducing and standard growth media, respectively. A total of 601 sRNAs were identified in the Xoo genome and ten virulent sRNA candidates were screened out based on significant differences of their expression levels between the culture conditions. In addition, trans3287 and trans3288 were also selected as candidates due to high expression levels in both media. The differential expression of 12 sRNAs evidenced by the sRNA-Seq data was confirmed by a convincing quantitative method. Based on genetic analysis of Xoo ΔsRNA mutants generated by deletion of the 12 single sRNAs, trans217 and trans3287 were characterized as virulent sRNAs. They are essential not only for the formation of bacterial blight in a susceptible rice variety Nipponbare but also for the induction of hypersensitive response (HR) in nonhost plant tobacco. Xoo Δtrans217 and Δtrans3287 mutants fail to induce bacterial blight in Nipponbare and also fail to induce the HR in tobacco, whereas, genetic complementation restores both mutants to the wild type in the virulent performance and HR induction. Similar effects of gene knockout and complementation were found in the expression of hrpG and hrpX genes, which encode regulatory proteins of the type III secretion system. Consistently, secretion of a type III effector, PthXo1, is blocked in Δtrans217 or Δtrans3287 bacterial cultures but retrieved by genetic complementation to both mutants. CONCLUSIONS The genetic analysis characterizes trans217 and trans3287 as pathogenicity-associated sRNAs essential for the bacterial virulence on the susceptible rice variety and for the HR elicitation in the nonhost plant. The molecular evidence suggests that both virulent sRNAs regulate the bacterial virulence by targeting the type III secretion system.
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Affiliation(s)
- Yiqun Hu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu Province China
| | - Liyuan Zhang
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
| | - Xuan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu Province China
| | - Fengli Sun
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
- Current Address: Rural Work Bureau of Zhangpu Town, Suzhou, 215300 Jiangsu Province China
| | - Xiangxin Kong
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
| | - Hansong Dong
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu Province China
| | - Heng Xu
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
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Wang X, Zhang L, Ji H, Mo X, Li P, Wang J, Dong H. Hpa1 is a type III translocator in Xanthomonas oryzae pv. oryzae. BMC Microbiol 2018; 18:105. [PMID: 30180793 PMCID: PMC6123991 DOI: 10.1186/s12866-018-1251-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 08/27/2018] [Indexed: 11/29/2022] Open
Abstract
Background Pathogenic Gram-negative bacteria interact with their eukaryotic hosts by deploying the type III translocon to inject effector proteins into the cytosol of eukaryotic cells. The translocon compositions, the number and biochemical characteristics of type III translocators in animal-pathogenic bacteria have been well elucidated, but information is lacking for plant-pathogenic bacteria. With extensive studies on biological functions of the Hpa1 protein secreted by the type III secretion system in Xanthomonas oryzae pv. oryzae (Xoo), we show here that Hpa1 is a type III translocator based on measurements of two proteins categorized as transcription activator-like (TAL) effector. Results Hpa1 was functionally associated with the TAL effector PthXo1 or AvrXa10 by genetic analysis of the wild-type Xoo strain and related mutants or recombinant strains. Inoculation experiments suggested that Hpa1 is required not only for the virulent role of PthXo1 in the susceptible rice variety Nipponbare, but also for the avirulent function of AvrXa10 on the resistant rice variety IRBB10. Hpa1 is unrelated to the secretion of PthXo1 and AvrXa10 out of bacterial cells. However, Hpa1 is critical for both TAL effectors to be translocated from bacterial cells into the cytosol of rice cells based on replicate experiments performed on the susceptible and resistant varieties, respectively. Hpa1-mediated translocation of PthXo1 is coincident with induced expression of rice SWEET11 gene, which is the regulatory target of PthXo1, resulting in the occurrence of the bacterial blight disease in the susceptible rice variety. By contrast, the immune hypersensitive response is induced in agreement with induced expression of rice Xa10 gene, which is the target of AvrXa10, only when AvrXa10 is translocated from bacteria into cells of the resistant rice variety. All the virulent or avirulent performances of the TAL effectors are nullified by directed mutation that removes the α-helix motif from the Hpa1 sequence. Conclusions The genetic and biochemical data demonstrate that Hap1 is a type III translocator at least for TAL effectors PthXo1 and AvrXa10. The effect of the directed mutation suggests that Hpa1 depends on its α-helical motif to fulfil the translocator function. Electronic supplementary material The online version of this article (10.1186/s12866-018-1251-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xuan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Liyuan Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Hongtao Ji
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China.,Present address: Department of Biology, College of Life Sciences, Jiangsu Formal University, Xuzhou, 221116, Jiangsu Province, China
| | - Xuyan Mo
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Ping Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Junzhi Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Hansong Dong
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China.
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Lawaju BR, Lawrence KS, Lawrence GW, Klink VP. Harpin-inducible defense signaling components impair infection by the ascomycete Macrophomina phaseolina. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 129:331-348. [PMID: 29936240 DOI: 10.1016/j.plaphy.2018.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 05/23/2023]
Abstract
Soybean (Glycine max) infection by the charcoal rot (CR) ascomycete Macrophomina phaseolina is enhanced by the soybean cyst nematode (SCN) Heterodera glycines. We hypothesized that G. max genetic lines impairing infection by M. phaseolina would also limit H. glycines parasitism, leading to resistance. As a part of this M. phaseolina resistance process, the genetic line would express defense genes already proven to impair nematode parasitism. Using G. max[DT97-4290/PI 642055], exhibiting partial resistance to M. phaseolina, experiments show the genetic line also impairs H. glycines parasitism. Furthermore, comparative studies show G. max[DT97-4290/PI 642055] exhibits induced expression of the effector triggered immunity (ETI) gene NON-RACE SPECIFIC DISEASE RESISTANCE 1/HARPIN INDUCED1 (NDR1/HIN1) that functions in defense to H. glycines as compared to the H. glycines and M. phaseolina susceptible line G. max[Williams 82/PI 518671]. Other defense genes that are induced in G. max[DT97-4290/PI 642055] include the pathogen associated molecular pattern (PAMP) triggered immunity (PTI) genes ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), NONEXPRESSOR OF PR1 (NPR1) and TGA2. These observations link G. max defense processes that impede H. glycines parasitism to also potentially function toward impairing M. phaseolina pathogenicity. Testing this hypothesis, G. max[Williams 82/PI 518671] genetically engineered to experimentally induce GmNDR1-1, EDS1-2, NPR1-2 and TGA2-1 expression leads to impaired M. phaseolina pathogenicity. In contrast, G. max[DT97-4290/PI 642055] engineered to experimentally suppress the expression of GmNDR1-1, EDS1-2, NPR1-2 and TGA2-1 by RNA interference (RNAi) enhances M. phaseolina pathogenicity. The results show components of PTI and ETI impair both nematode and M. phaseolina pathogenicity.
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Affiliation(s)
- Bisho R Lawaju
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, College of Agriculture and Life Sciences, Mississippi State, MS, 39762, USA.
| | - Kathy S Lawrence
- Department of Entomology and Plant Pathology, Auburn University, 209 Life Science Building, Auburn, AL, 36849, USA.
| | - Gary W Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, College of Agriculture and Life Sciences, Mississippi State University, Mississippi State, MS, 39762, USA.
| | - Vincent P Klink
- Department of Biological Sciences, College of Arts and Sciences, Mississippi State University, Mississippi State, MS, 39762, USA.
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Wei H, Collmer A. Defining essential processes in plant pathogenesis with Pseudomonas syringae pv. tomato DC3000 disarmed polymutants and a subset of key type III effectors. MOLECULAR PLANT PATHOLOGY 2018; 19:1779-1794. [PMID: 29277959 PMCID: PMC6638048 DOI: 10.1111/mpp.12655] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 11/10/2017] [Accepted: 12/20/2017] [Indexed: 05/22/2023]
Abstract
Pseudomonas syringae pv. tomato DC3000 and its derivatives cause disease in tomato, Arabidopsis and Nicotiana benthamiana. The primary virulence factors include a repertoire of 29 effector proteins injected into plant cells by the type III secretion system and the phytotoxin coronatine. The complete repertoire of effector genes and key coronatine biosynthesis genes have been progressively deleted and minimally reassembled to reconstitute basic pathogenic ability in N. benthamiana, and in Arabidopsis plants that have mutations in target genes that mimic effector actions. This approach and molecular studies of effector activities and plant immune system targets have highlighted a small subset of effectors that contribute to essential processes in pathogenesis. Most notably, HopM1 and AvrE1 redundantly promote an aqueous apoplastic environment, and AvrPtoB and AvrPto redundantly block early immune responses, two conditions that are sufficient for substantial bacterial growth in planta. In addition, disarmed DC3000 polymutants have been used to identify the individual effectors responsible for specific activities of the complete repertoire and to more effectively study effector domains, effector interplay and effector actions on host targets. Such work has revealed that AvrPtoB suppresses cell death elicitation in N. benthamiana that is triggered by another effector in the DC3000 repertoire, highlighting an important aspect of effector interplay in native repertoires. Disarmed DC3000 polymutants support the natural delivery of test effectors and infection readouts that more accurately reveal effector functions in key pathogenesis processes, and enable the identification of effectors with similar activities from a broad range of other pathogens that also defeat plants with cytoplasmic effectors.
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Affiliation(s)
- Hai‐Lei Wei
- School of Integrative Plant ScienceSection of Plant Pathology and Plant–Microbe Biology, Cornell UniversityIthacaNY14853USA
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of AgricultureInstitute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural SciencesBeijing100081China
| | - Alan Collmer
- School of Integrative Plant ScienceSection of Plant Pathology and Plant–Microbe Biology, Cornell UniversityIthacaNY14853USA
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29
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Abstract
An accurate and complete roster of the Type III effector (T3E) proteins translocated by the P. syringae Type III secretion system (T3SS) into host cells is critical to understanding the pathogen's interactions with plants. The adenylate cyclase (Cya) reporter offers a highly sensitive and robust assay for monitoring the translocation of T3Es. T3Es are fused to the calmodulin-dependent adenylate-cyclase domain of CyaA. The T3E targets Cya for translocation through the T3SS into the host cell at which point it is activated by calmodulin and converts adenosine triphosphate into cyclic adenosine monophosphate (cAMP). The T3SS translocation-dependent increase in cAMP concentration in plant cells is then measured with an enzyme-linked immunosorbent assay kit. The Cya reporter can be used to determine whether a candidate protein is translocated by T3SS or to measure relative levels of T3SS translocation in a semiquantitative manner.
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30
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Medina CA, Reyes PA, Trujillo CA, Gonzalez JL, Bejarano DA, Montenegro NA, Jacobs JM, Joe A, Restrepo S, Alfano JR, Bernal A. The role of type III effectors from Xanthomonas axonopodis pv. manihotis in virulence and suppression of plant immunity. MOLECULAR PLANT PATHOLOGY 2018; 19:593-606. [PMID: 28218447 PMCID: PMC6638086 DOI: 10.1111/mpp.12545] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 01/25/2017] [Accepted: 02/15/2017] [Indexed: 05/29/2023]
Abstract
Xanthomonas axonopodis pv. manihotis (Xam) causes cassava bacterial blight, the most important bacterial disease of cassava. Xam, like other Xanthomonas species, requires type III effectors (T3Es) for maximal virulence. Xam strain CIO151 possesses 17 predicted T3Es belonging to the Xanthomonas outer protein (Xop) class. This work aimed to characterize nine Xop effectors present in Xam CIO151 for their role in virulence and modulation of plant immunity. Our findings demonstrate the importance of XopZ, XopX, XopAO1 and AvrBs2 for full virulence, as well as a redundant function in virulence between XopN and XopQ in susceptible cassava plants. We tested their role in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) using heterologous systems. AvrBs2, XopR and XopAO1 are capable of suppressing PTI. ETI suppression activity was only detected for XopE4 and XopAO1. These results demonstrate the overall importance and diversity in functions of major virulence effectors AvrBs2 and XopAO1 in Xam during cassava infection.
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Affiliation(s)
- Cesar Augusto Medina
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Paola Andrea Reyes
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Cesar Augusto Trujillo
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Juan Luis Gonzalez
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - David Alejandro Bejarano
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Nathaly Andrea Montenegro
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Jonathan M. Jacobs
- Institut de Recherche pour le De´veloppement (IRD), CiradUniversite´ Montpellier, Interactions Plantes Microorganismes Environnement (IPME), 34394MontpellierFrance
| | - Anna Joe
- Center for Plant Science InnovationUniversity of NebraskaLincolnNE68588‐0660USA
- Department of Plant PathologyUniversity of NebraskaLincolnNE68588‐0722USA
- Present address:
Department of Plant Pathology and the Genome CenterUniversity of California, Davis, CA 95616, USA, and Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Silvia Restrepo
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - James R. Alfano
- Center for Plant Science InnovationUniversity of NebraskaLincolnNE68588‐0660USA
- Department of Plant PathologyUniversity of NebraskaLincolnNE68588‐0722USA
| | - Adriana Bernal
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
- Present address:
Novozymes, Inc., DavisCA95618USA
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Aljaafri WAR, McNeece BT, Lawaju BR, Sharma K, Niruala PM, Pant SR, Long DH, Lawrence KS, Lawrence GW, Klink VP. A harpin elicitor induces the expression of a coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene and others functioning during defense to parasitic nematodes. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 121:161-175. [PMID: 29107936 DOI: 10.1016/j.plaphy.2017.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 05/23/2023]
Abstract
The bacterial effector harpin induces the transcription of the Arabidopsis thaliana NON-RACE SPECIFIC DISEASE RESISTANCE 1/HARPIN INDUCED1 (NDR1/HIN1) coiled-coil nucleotide binding leucine rich repeat (CC-NB-LRR) defense signaling gene. In Glycine max, Gm-NDR1-1 transcripts have been detected within root cells undergoing a natural resistant reaction to parasitism by the syncytium-forming nematode Heterodera glycines, functioning in the defense response. Expressing Gm-NDR1-1 in Gossypium hirsutum leads to resistance to Meloidogyne incognita parasitism. In experiments presented here, the heterologous expression of Gm-NDR1-1 in G. hirsutum impairs Rotylenchulus reniformis parasitism. These results are consistent with the hypothesis that Gm-NDR1-1 expression functions broadly in generating a defense response. To examine a possible relationship with harpin, G. max plants topically treated with harpin result in induction of the transcription of Gm-NDR1-1. The result indicates the topical treatment of plants with harpin, itself, may lead to impaired nematode parasitism. Topical harpin treatments are shown to impair G. max parasitism by H. glycines, M. incognita and R. reniformis and G. hirsutum parasitism by M. incognita and R. reniformis. How harpin could function in defense has been examined in experiments showing it also induces transcription of G. max homologs of the proven defense genes ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1), TGA2, galactinol synthase, reticuline oxidase, xyloglucan endotransglycosylase/hydrolase, alpha soluble N-ethylmaleimide-sensitive fusion protein (α-SNAP) and serine hydroxymethyltransferase (SHMT). In contrast, other defense genes are not directly transcriptionally activated by harpin. The results indicate harpin induces pathogen associated molecular pattern (PAMP) triggered immunity (PTI) and effector-triggered immunity (ETI) defense processes in the root, activating defense to parasitic nematodes.
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Affiliation(s)
- Weasam A R Aljaafri
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Brant T McNeece
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Bisho R Lawaju
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Keshav Sharma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Prakash M Niruala
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Shankar R Pant
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
| | - David H Long
- Albaugh, LLC, 4060 Dawkins Farm Drive, Olive Branch, MS 38654, United States.
| | - Kathy S Lawrence
- Department of Entomology and Plant Pathology, Auburn University, 209 Life Science Building, Auburn, AL 36849, United States.
| | - Gary W Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, United States.
| | - Vincent P Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, United States.
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Scheibner F, Marillonnet S, Büttner D. The TAL Effector AvrBs3 from Xanthomonas campestris pv. vesicatoria Contains Multiple Export Signals and Can Enter Plant Cells in the Absence of the Type III Secretion Translocon. Front Microbiol 2017; 8:2180. [PMID: 29170655 PMCID: PMC5684485 DOI: 10.3389/fmicb.2017.02180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/24/2017] [Indexed: 12/27/2022] Open
Abstract
Pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion (T3S) system which translocates effector proteins into plant cells. Effector protein delivery is controlled by the T3S chaperone HpaB, which presumably escorts effector proteins to the secretion apparatus. One intensively studied effector is the transcription activator-like (TAL) effector AvrBs3, which binds to promoter sequences of plant target genes and activates plant gene expression. It was previously reported that type III-dependent delivery of AvrBs3 depends on the N-terminal protein region. The signals that control T3S and translocation of AvrBs3, however, have not yet been characterized. In the present study, we show that T3S and translocation of AvrBs3 depend on the N-terminal 10 and 50 amino acids, respectively. Furthermore, we provide experimental evidence that additional signals in the N-terminal 30 amino acids and the region between amino acids 64 and 152 promote translocation of AvrBs3 in the absence of HpaB. Unexpectedly, in vivo translocation assays revealed that AvrBs3 is delivered into plant cells even in the absence of HrpF, which is the predicted channel-forming component of the T3S translocon in the plant plasma membrane. The presence of HpaB- and HrpF-independent transport routes suggests that the delivery of AvrBs3 is initiated during early stages of the infection process, presumably before the activation of HpaB or the insertion of the translocon into the plant plasma membrane.
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Affiliation(s)
- Felix Scheibner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle, Germany
| | | | - Daniela Büttner
- Institute of Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, Halle, Germany
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Pesce C, Jacobs JM, Berthelot E, Perret M, Vancheva T, Bragard C, Koebnik R. Comparative Genomics Identifies a Novel Conserved Protein, HpaT, in Proteobacterial Type III Secretion Systems that Do Not Possess the Putative Translocon Protein HrpF. Front Microbiol 2017; 8:1177. [PMID: 28694803 PMCID: PMC5483457 DOI: 10.3389/fmicb.2017.01177] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/09/2017] [Indexed: 01/09/2023] Open
Abstract
Xanthomonas translucens is the causal agent of bacterial leaf streak, the most common bacterial disease of wheat and barley. To cause disease, most xanthomonads depend on a highly conserved type III secretion system, which translocates type III effectors into host plant cells. Mutagenesis of the conserved type III secretion gene hrcT confirmed that the X. translucens type III secretion system is required to cause disease on the host plant barley and to trigger a non-host hypersensitive response (HR) in pepper leaves. Type III effectors are delivered to the host cell by a surface appendage, the Hrp pilus, and a translocon protein complex that inserts into the plant cell plasma membrane. Homologs of the Xanthomonas HrpF protein, including PopF from Ralstonia solanacearum and NolX from rhizobia, are thought to act as a translocon protein. Comparative genomics revealed that X. translucens strains harbor a noncanonical hrp gene cluster, which rather shares features with type III secretion systems from Ralstonia solanacearum, Paraburkholderia andropogonis, Collimonas fungivorans, and Uliginosibacterium gangwonense than other Xanthomonas spp. Surprisingly, none of these bacteria, except R. solanacearum, encode a homolog of the HrpF translocon. Here, we aimed at identifying a candidate translocon from X. translucens. Notably, genomes from strains that lacked hrpF/popF/nolX instead encode another gene, called hpaT, adjacent to and co-regulated with the type III secretion system gene cluster. An insertional mutant in the X. translucens hpaT gene, which is the first gene of a two-gene operon, hpaT-hpaH, was non-pathogenic on barley and did not cause the HR or programmed cell death in non-host pepper similar to the hrcT mutant. The hpaT mutant phenotypes were partially complemented by either hpaT or the downstream gene, hpaH, which has been described as a facilitator of translocation in Xanthomonas oryzae. Interestingly, the hpaT mutant was also complemented by the hrpF gene from Xanthomonas euvesicatoria. These findings reveal that both HpaT and HpaH contribute to the injection of type III effectors into plant cells.
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Affiliation(s)
- Céline Pesce
- UMR 186 IRD-Cirad-Université Montpellier IPMEMontpellier, France
- Applied Microbiology Phytopathology, Earth and Life Institute, Université catholique de LouvainLouvain-la-Neuve, Belgium
| | - Jonathan M. Jacobs
- UMR 186 IRD-Cirad-Université Montpellier IPMEMontpellier, France
- Applied Microbiology Phytopathology, Earth and Life Institute, Université catholique de LouvainLouvain-la-Neuve, Belgium
| | - Edwige Berthelot
- UMR 186 IRD-Cirad-Université Montpellier IPMEMontpellier, France
| | - Marion Perret
- UMR 186 IRD-Cirad-Université Montpellier IPMEMontpellier, France
| | - Taca Vancheva
- UMR 186 IRD-Cirad-Université Montpellier IPMEMontpellier, France
- Applied Microbiology Phytopathology, Earth and Life Institute, Université catholique de LouvainLouvain-la-Neuve, Belgium
| | - Claude Bragard
- Applied Microbiology Phytopathology, Earth and Life Institute, Université catholique de LouvainLouvain-la-Neuve, Belgium
| | - Ralf Koebnik
- UMR 186 IRD-Cirad-Université Montpellier IPMEMontpellier, France
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Castañeda‐Ojeda MP, López‐Solanilla E, Ramos C. Differential modulation of plant immune responses by diverse members of the Pseudomonas savastanoi pv. savastanoi HopAF type III effector family. MOLECULAR PLANT PATHOLOGY 2017; 18:625-634. [PMID: 27116193 PMCID: PMC6638205 DOI: 10.1111/mpp.12420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 05/25/2023]
Abstract
The Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system (T3SS) effector repertoire includes 33 candidates, seven of which translocate into host cells and interfere with plant defences. The present study was performed to investigate the co-existence of both plasmid- and chromosomal-encoded members of the HopAF effector family, HopAF1-1 and HopAF1-2, respectively, in the genome of NCPPB 3335. Here, we show that the HopAF1 paralogues are widely distributed in the Pseudomonas syringae complex, where HopAF1-1 is most similar to the homologues encoded by other P. syringae pathovars infecting woody hosts that belong to phylogroups 1 and 3. We show that the expression of both HopAF1-1 and HopAF-2 is transcriptionally dependent on HrpL and demonstrate their delivery into Nicotiana tabacum leaves. Although the heterologous delivery of either HopAF1-1 or HopAF1-2 significantly suppressed the production of defence-associated reactive oxygen species levels, only HopAF1-2 reduced the levels of callose deposition. Moreover, the expression of HopAF1-2 by functionally effectorless P. syringae pv. tomato DC3000D28E completely inhibited the hypersensitive response in tobacco and significantly increased the competitiveness of the strain in Nicotiana benthamiana. Despite their functional differences, subcellular localization studies reveal that green fluorescent protein (GFP) fusions to either HopAF1-1 or HopAF1-2 are targeted to the plasma membrane when they are expressed in plant cells, a process that is completely dependent on the integrity of their N-myristoylation motif. Our results further support the notion that highly similar T3SS effectors might differentially interact with diverse plant targets, even when they co-localize in the same cell compartment.
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Affiliation(s)
- M. Pilar Castañeda‐Ojeda
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga‐Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC)Campus Teatinos s/nMálagaE‐29010Spain
| | - Emilia López‐Solanilla
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid‐Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Parque Científico y Tecnológico de la UPM, Campus de MontegancedoPozuelo de AlarcónMadrid28223Spain
- Departamento de BiotecnologíaEscuela Técnica Superior de Ingenieros Agrónomos, UPMAvda. Complutense S/NMadrid28040Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga‐Consejo Superior de Investigaciones Científicas (IHSM‐UMA‐CSIC)Campus Teatinos s/nMálagaE‐29010Spain
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Castañeda-Ojeda MP, Moreno-Pérez A, Ramos C, López-Solanilla E. Suppression of Plant Immune Responses by the Pseudomonas savastanoi pv. savastanoi NCPPB 3335 Type III Effector Tyrosine Phosphatases HopAO1 and HopAO2. FRONTIERS IN PLANT SCIENCE 2017; 8:680. [PMID: 28529516 PMCID: PMC5418354 DOI: 10.3389/fpls.2017.00680] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/13/2017] [Indexed: 05/12/2023]
Abstract
The effector repertoire of the olive pathogen P. savastanoi pv. savastanoi NCPPB 3335 includes two members of the HopAO effector family, one of the most diverse T3E families of the P. syringae complex. The study described here explores the phylogeny of these dissimilar members, HopAO1 and HopAO2, among the complex and reveals their activities as immune defense suppressors. Although HopAO1 is predominantly encoded by phylogroup 3 strains isolated from woody organs of woody hosts, both HopAO1 and HopAO2 are phylogenetically clustered according to the woody/herbaceous nature of their host of isolation, suggesting host specialization of the HopAO family across the P. syringae complex. HopAO1 and HopAO2 translocate into plant cells and show hrpL-dependent expression, which allows their classification as actively deployed type III effectors. Our data also show that HopAO1 and HopAO2 possess phosphatase activity, a hallmark of the members of this family. Both of them exert an inhibitory effect on early plant defense responses, such as ROS production and callose deposition, and are able to suppress ETI responses induced by the effectorless polymutant of P. syringae pv. tomato DC3000 (DC3000D28E) in Nicotiana. Moreover, we demonstrate that a ΔhopAO1 mutant of P. savastanoi NCPBB 3335 exhibits a reduced fitness and virulence in olive plants, which supports the relevance of this effector during the interaction of this strain with its host plants. This work contributes to the field with the first report regarding functional analysis of HopAO homologs encoded by P. syringae or P. savastanoi strains isolated from woody hosts.
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Affiliation(s)
- María Pilar Castañeda-Ojeda
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Alba Moreno-Pérez
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Emilia López-Solanilla
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid – Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Parque Científico y Tecnológico de la UPMMadrid, Spain
- Departamento de Biotecnología y Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de MadridMadrid, Spain
- *Correspondence: Emilia López-Solanilla,
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McCraw SL, Park DH, Jones R, Bentley MA, Rico A, Ratcliffe RG, Kruger NJ, Collmer A, Preston GM. GABA (γ-Aminobutyric Acid) Uptake Via the GABA Permease GabP Represses Virulence Gene Expression in Pseudomonas syringae pv. tomato DC3000. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:938-949. [PMID: 28001093 DOI: 10.1094/mpmi-08-16-0172-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The nonprotein amino acid γ-aminobutyric acid (GABA) is the most abundant amino acid in the tomato (Solanum lycopersicum) leaf apoplast and is synthesized by Arabidopsis thaliana in response to infection by the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (hereafter called DC3000). High levels of exogenous GABA have previously been shown to repress the expression of the type III secretion system (T3SS) in DC3000, resulting in reduced elicitation of the hypersensitive response (HR) in the nonhost plant tobacco (Nicotiana tabacum). This study demonstrates that the GABA permease GabP provides the primary mechanism for GABA uptake by DC3000 and that the gabP deletion mutant ΔgabP is insensitive to GABA-mediated repression of T3SS expression. ΔgabP displayed an enhanced ability to elicit the HR in young tobacco leaves and in tobacco plants engineered to produce increased levels of GABA, which supports the hypothesis that GABA uptake via GabP acts to regulate T3SS expression in planta. The observation that P. syringae can be rendered insensitive to GABA through loss of gabP but that gabP is retained by this bacterium suggests that GabP is important for DC3000 in a natural setting, either for nutrition or as a mechanism for regulating gene expression. [Formula: see text] Copyright © 2016 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- S L McCraw
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - D H Park
- 2 Department of Applied Biology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea
| | - R Jones
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - M A Bentley
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - A Rico
- 3 Departamento de Didáctica de la 9 Matemática y de las Ciencias Experimentales, Faculty of Education and Sport, University of the Basque Country UPV/EHU, Juan Ibañez de Sto. Domingo 1, 01006 Vitoria-Gasteiz, Spain; and
| | - R G Ratcliffe
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - N J Kruger
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - A Collmer
- 4 School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, U.S.A
| | - G M Preston
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
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37
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Contributions of host cellular trafficking and organization to the outcomes of plant-pathogen interactions. Semin Cell Dev Biol 2016; 56:163-173. [DOI: 10.1016/j.semcdb.2016.05.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/16/2016] [Accepted: 05/20/2016] [Indexed: 11/23/2022]
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38
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Shah R, Pathak G, Drepper T, Gärtner W. Selective Photoreceptor Gene Knock-out Reveals a Regulatory Role for the Growth Behavior ofPseudomonas syringae. Photochem Photobiol 2016; 92:571-8. [DOI: 10.1111/php.12610] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/06/2016] [Indexed: 12/23/2022]
Affiliation(s)
- Rashmi Shah
- Max-Planck-Institute for Chemical Energy Conversion; Mülheim Germany
| | - Gopal Pathak
- Max-Planck-Institute for Chemical Energy Conversion; Mülheim Germany
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology; Heinrich Heine University Düsseldorf; Forschungszentrum Jülich; Jülich Germany
| | - Wolfgang Gärtner
- Max-Planck-Institute for Chemical Energy Conversion; Mülheim Germany
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Tian S, Wang X, Li P, Wang H, Ji H, Xie J, Qiu Q, Shen D, Dong H. Plant Aquaporin AtPIP1;4 Links Apoplastic H2O2 Induction to Disease Immunity Pathways. PLANT PHYSIOLOGY 2016; 171:1635-50. [PMID: 26945050 PMCID: PMC4936539 DOI: 10.1104/pp.15.01237] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 03/03/2016] [Indexed: 05/18/2023]
Abstract
Hydrogen peroxide (H2O2) is a stable component of reactive oxygen species, and its production in plants represents the successful recognition of pathogen infection and pathogen-associated molecular patterns (PAMPs). This production of H2O2 is typically apoplastic but is subsequently associated with intracellular immunity pathways that regulate disease resistance, such as systemic acquired resistance and PAMP-triggered immunity. Here, we elucidate that an Arabidopsis (Arabidopsis thaliana) aquaporin (i.e. the plasma membrane intrinsic protein AtPIP1;4) acts to close the cytological distance between H2O2 production and functional performance. Expression of the AtPIP1;4 gene in plant leaves is inducible by a bacterial pathogen, and the expression accompanies H2O2 accumulation in the cytoplasm. Under de novo expression conditions, AtPIP1;4 is able to mediate the translocation of externally applied H2O2 into the cytoplasm of yeast (Saccharomyces cerevisiae) cells. In plant cells treated with H2O2, AtPIP1;4 functions as an effective facilitator of H2O2 transport across plasma membranes and mediates the translocation of externally applied H2O2 from the apoplast to the cytoplasm. The H2O2-transport role of AtPIP1;4 is essentially required for the cytoplasmic import of apoplastic H2O2 induced by the bacterial pathogen and two typical PAMPs in the absence of induced production of intracellular H2O2 As a consequence, cytoplasmic H2O2 quantities increase substantially while systemic acquired resistance and PAMP-triggered immunity are activated to repress the bacterial pathogenicity. By contrast, loss-of-function mutation at the AtPIP1;4 gene locus not only nullifies the cytoplasmic import of pathogen- and PAMP-induced apoplastic H2O2 but also cancels the subsequent immune responses, suggesting a pivotal role of AtPIP1;4 in apocytoplastic signal transduction in immunity pathways.
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Affiliation(s)
- Shan Tian
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaobing Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Ping Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hongtao Ji
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Junyi Xie
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Qinglei Qiu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Dan Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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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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41
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Li L, Wang H, Gago J, Cui H, Qian Z, Kodama N, Ji H, Tian S, Shen D, Chen Y, Sun F, Xia Z, Ye Q, Sun W, Flexas J, Dong H. Harpin Hpa1 Interacts with Aquaporin PIP1;4 to Promote the Substrate Transport and Photosynthesis in Arabidopsis. Sci Rep 2015; 5:17207. [PMID: 26607179 PMCID: PMC4660436 DOI: 10.1038/srep17207] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/27/2015] [Indexed: 12/12/2022] Open
Abstract
Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO2 and H2O. In particular, AtPIP1;4 mediates CO2 transport with a substantial contribute to photosynthesis and further increases this function upon interacting with Hpa1 at the plasma membrane. As a result, leaf photosynthesis rates are increased and the plant growth is enhanced in contrast to the normal process without Hpa1-AtPIP1;4 interaction. Our findings demonstrate the first case that plant sensing of a bacterial harpin protein is connected with photosynthetic physiology to regulate plant growth.
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Affiliation(s)
- Liang Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jorge Gago
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears 07122, Spain
| | - Haiying Cui
- Institute of Grassland Science, Northeast Normal University and National Ministry of Education Key Laboratory of Vegetation Ecology, Changchun 130024, China
| | - Zhengjiang Qian
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Naomi Kodama
- Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, Tsukuba 305-8604, Japan
| | - Hongtao Ji
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Shan Tian
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Dan Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanjuan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Fengli Sun
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhonglan Xia
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Qing Ye
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Wei Sun
- Institute of Grassland Science, Northeast Normal University and National Ministry of Education Key Laboratory of Vegetation Ecology, Changchun 130024, China
| | - Jaume Flexas
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears 07122, Spain
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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Ji H, Dong H. Key steps in type III secretion system (T3SS) towards translocon assembly with potential sensor at plant plasma membrane. MOLECULAR PLANT PATHOLOGY 2015; 16:762-73. [PMID: 25469869 PMCID: PMC6638502 DOI: 10.1111/mpp.12223] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Many plant- and animal-pathogenic Gram-negative bacteria employ the type III secretion system (T3SS) to translocate effector proteins from bacterial cells into the cytosol of eukaryotic host cells. The effector translocation occurs through an integral component of T3SS, the channel-like translocon, assembled by hydrophilic and hydrophobic proteinaceous translocators in a two-step process. In the first, hydrophilic translocators localize to the tip of a proteinaceous needle in animal pathogens, or a proteinaceous pilus in plant pathogens, and associate with hydrophobic translocators, which insert into host plasma membranes in the second step. However, the pilus needs to penetrate plant cell walls in advance. All hydrophilic translocators so far identified in plant pathogens are characteristic of harpins: T3SS accessory proteins containing a unitary hydrophilic domain or an additional enzymatic domain. Two-domain harpins carrying a pectate lyase domain potentially target plant cell walls and facilitate the penetration of the pectin-rich middle lamella by the bacterial pilus. One-domain harpins target plant plasma membranes and may play a crucial role in translocon assembly, which may also involve contrapuntal associations of hydrophobic translocators. In all cases, sensory components in the target plasma membrane are indispensable for the membrane recognition of translocators and the functionality of the translocon. The conjectural sensors point to membrane lipids and proteins, and a phosphatidic acid and an aquaporin are able to interact with selected harpin-type translocators. Interactions between translocators and their sensors at the target plasma membrane are assumed to be critical for translocon assembly.
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Affiliation(s)
- Hongtao Ji
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
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Xin XF, Nomura K, Ding X, Chen X, Wang K, Aung K, Uribe F, Rosa B, Yao J, Chen J, He SY. Pseudomonas syringae Effector Avirulence Protein E Localizes to the Host Plasma Membrane and Down-Regulates the Expression of the NONRACE-SPECIFIC DISEASE RESISTANCE1/HARPIN-INDUCED1-LIKE13 Gene Required for Antibacterial Immunity in Arabidopsis. PLANT PHYSIOLOGY 2015; 169. [PMID: 26206852 PMCID: PMC4577396 DOI: 10.1104/pp.15.00547] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Many bacterial pathogens of plants and animals deliver effector proteins into host cells to promote infection. Elucidation of how pathogen effector proteins function not only is critical for understanding bacterial pathogenesis but also provides a useful tool in discovering the functions of host genes. In this study, we characterized the Pseudomonas syringae pv tomato DC3000 effector protein Avirulence Protein E (AvrE), the founding member of a widely distributed, yet functionally enigmatic, bacterial effector family. We show that AvrE is localized in the plasma membrane (PM) and PM-associated vesicle-like structures in the plant cell. AvrE contains two physically interacting domains, and the amino-terminal portion contains a PM-localization signal. Genome-wide microarray analysis indicates that AvrE, as well as the functionally redundant effector Hypersensitive response and pathogenicity-dependent Outer Protein M1, down-regulates the expression of the NONRACE-SPECIFIC DISEASE RESISTANCE1/HARPIN-INDUCED1-LIKE13 (NHL13) gene in Arabidopsis (Arabidopsis thaliana). Mutational analysis shows that NHL13 is required for plant immunity, as the nhl13 mutant plant displayed enhanced disease susceptibility. Our results defined the action site of one of the most important bacterial virulence proteins in plants and the antibacterial immunity function of the NHL13 gene.
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Affiliation(s)
- Xiu-Fang Xin
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Kinya Nomura
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Xinhua Ding
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Xujun Chen
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Kun Wang
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Kyaw Aung
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Francisco Uribe
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Bruce Rosa
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Jian Yao
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Jin Chen
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
| | - Sheng Yang He
- Department of Energy Plant Research Laboratory (X.-F.X., K.N., X.D., X.C., K.A., F.U., B.R., J.Y., J.C., S.Y.H.), Department of Plant Biology (X.-F.X.), Department of Biochemistry and Molecular Biology (K.W.), and Howard Hughes Medical Institute (S.Y.H.), Michigan State University, East Lansing, Michigan 48824;State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018 Shandong, China (X.D.);Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing 100193, China (X.C.);Genome Institute, Washington University, St. Louis, Missouri 63108 (B.R.); andDepartment of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008 (J.Y.)
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Wei HL, Chakravarthy S, Mathieu J, Helmann TC, Stodghill P, Swingle B, Martin GB, Collmer A. Pseudomonas syringae pv. tomato DC3000 Type III Secretion Effector Polymutants Reveal an Interplay between HopAD1 and AvrPtoB. Cell Host Microbe 2015; 17:752-62. [PMID: 26067603 PMCID: PMC4471848 DOI: 10.1016/j.chom.2015.05.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 03/05/2015] [Accepted: 04/17/2015] [Indexed: 11/20/2022]
Abstract
The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 suppresses the two-tiered plant innate immune system by injecting a complex repertoire of type III secretion effector (T3E) proteins. Beyond redundancy and interplay, individual T3Es may interact with multiple immunity-associated proteins, rendering their analysis challenging. We constructed a Pst DC3000 polymutant lacking all 36 T3Es and restored individual T3Es or their mutants to explore the interplay among T3Es. The weakly expressed T3E HopAD1 was sufficient to elicit immunity-associated cell death in Nicotiana benthamiana. HopAD1-induced cell death was suppressed partially by native AvrPtoB and completely by AvrPtoBM3, which has mutations disrupting its E3 ubiquitin ligase domain and two known domains for interacting with immunity-associated kinases. AvrPtoBM3 also gained the ability to interact with the immunity-kinase MKK2, which is required for HopAD1-dependent cell death. Thus, AvrPtoB has alternative, competing mechanisms for suppressing effector-triggered plant immunity. This approach allows the deconvolution of individual T3E activities.
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Affiliation(s)
- Hai-Lei Wei
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Suma Chakravarthy
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Johannes Mathieu
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
| | - Tyler C Helmann
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Paul Stodghill
- United States Department of Agriculture-Agricultural Research Service, Ithaca, NY 14853, USA
| | - Bryan Swingle
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; United States Department of Agriculture-Agricultural Research Service, Ithaca, NY 14853, USA
| | - Gregory B Martin
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
| | - Alan Collmer
- School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
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Liu P, Zhang W, Zhang LQ, Liu X, Wei HL. Supramolecular Structure and Functional Analysis of the Type III Secretion System in Pseudomonas fluorescens 2P24. FRONTIERS IN PLANT SCIENCE 2015; 6:1190. [PMID: 26779224 PMCID: PMC4700148 DOI: 10.3389/fpls.2015.01190] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 12/11/2015] [Indexed: 05/14/2023]
Abstract
The type III secretion system (T3SS) of plant and animal bacterial pathogens directs the secretion and injection of proteins into host cells. Some homologous genes of T3SS were found also in non-pathogenic bacteria, but the organization of its machinery and basic function are still unknown. In this study, we identified a T3SS gene cluster from the plant growth-promoting Pseudomonas fluorescens 2P24 and isolated the corresponding T3SS apparatus. The T3SS gene cluster of strain 2P24 is similar organizationally to that of pathogenic P. syringae, except that it lacks the regulator hrpR and the hrpK1 and hrpH genes, which are involved in translocation of proteins. Electron microscopy revealed that the T3SS supramolecular structure of strain 2P24 was comprised of two distinctive substructures: a long extracellular, filamentous pilus, and a membrane-embedded base. We show that strain 2P24 deploys a harpin homolog protein, RspZ1, to elicit a hypersensitive response when infiltrated into Nicotiana tabacum cv. xanthi leaves with protein that is partially purified, and by complementing the hrpZ1 mutation of pHIR11. The T3SS of strain 2P24 retained ability to secrete effectors, whereas its effector translocation activity appeared to be excessively lost. Mutation of the rscC gene from 2P24 T3SS abolished the secretion of effectors, but the general biocontrol properties were unaffected. Remarkably, strain 2P24 induced functional MAMP-triggered immunity that included a burst of reactive oxygen species, strong suppression of challenge cell death, and disease expansion, while it was not associated with the secretion functional T3SS.
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Affiliation(s)
- Ping Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of SciencesBeijing, China
| | - Wei Zhang
- Department of Plant Pathology, China Agricultural UniversityBeijing, China
- MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power UniversityBeijing, China
| | - Li-Qun Zhang
- Department of Plant Pathology, China Agricultural UniversityBeijing, China
| | - Xingzhong Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of SciencesBeijing, China
| | - Hai-Lei Wei
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of SciencesBeijing, China
- *Correspondence: Hai-Lei Wei,
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Lam HN, Chakravarthy S, Wei HL, BuiNguyen H, Stodghill PV, Collmer A, Swingle BM, Cartinhour SW. Global analysis of the HrpL regulon in the plant pathogen Pseudomonas syringae pv. tomato DC3000 reveals new regulon members with diverse functions. PLoS One 2014; 9:e106115. [PMID: 25170934 PMCID: PMC4149516 DOI: 10.1371/journal.pone.0106115] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/28/2014] [Indexed: 11/18/2022] Open
Abstract
The type III secretion system (T3SS) is required for virulence in the gram-negative plant pathogen Pseudomonas syringae pv. tomato DC3000. The alternative sigma factor HrpL directly regulates expression of T3SS genes via a promoter sequence, often designated as the "hrp promoter." Although the HrpL regulon has been extensively investigated in DC3000, it is not known whether additional regulon members remain to be found. To systematically search for HrpL-regulated genes, we used chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) and bulk mRNA sequencing (RNA-Seq) to identify HrpL-binding sites and likely hrp promoters. The analysis recovered 73 sites of interest, including 20 sites that represent new hrp promoters. The new promoters lie upstream of a diverse set of genes encoding potential regulators, enzymes and hypothetical proteins. PSPTO_5633 is the only new HrpL regulon member that is potentially an effector and is now designated HopBM1. Deletions in several other new regulon members, including PSPTO_5633, PSPTO_0371, PSPTO_2130, PSPTO_2691, PSPTO_2696, PSPTO_3331, and PSPTO_5240, in either DC3000 or ΔhopQ1-1 backgrounds, do not affect the hypersensitive response or in planta growth of the resulting strains. Many new HrpL regulon members appear to be unrelated to the T3SS, and orthologs for some of these can be identified in numerous non-pathogenic bacteria. With the identification of 20 new hrp promoters, the list of HrpL regulon members is approaching saturation and most likely includes all DC3000 effectors.
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Affiliation(s)
- Hanh N. Lam
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Suma Chakravarthy
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - HoangChuong BuiNguyen
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Paul V. Stodghill
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Bryan M. Swingle
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Samuel W. Cartinhour
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
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Matas IM, Castañeda-Ojeda MP, Aragón IM, Antúnez-Lamas M, Murillo J, Rodríguez-Palenzuela P, López-Solanilla E, Ramos C. Translocation and functional analysis of Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system effectors reveals two novel effector families of the Pseudomonas syringae complex. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:424-36. [PMID: 24329173 DOI: 10.1094/mpmi-07-13-0206-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pseudomonas savastanoi pv. savastanoi NCPPB 3335 causes olive knot disease and is a model pathogen for exploring bacterial infection of woody hosts. The type III secretion system (T3SS) effector repertoire of this strain includes 31 effector candidates plus two novel candidates identified in this study which have not been reported to translocate into plant cells. In this work, we demonstrate the delivery of seven NCPPB 3335 effectors into Nicotiana tabacum leaves, including three proteins from two novel families of the P. syringae complex effector super-repertoire (HopBK and HopBL), one of which comprises two proteins (HopBL1 and HopBL2) that harbor a SUMO protease domain. When delivered by P. fluorescens heterologously expressing a P. syringae T3SS, all seven effectors were found to suppress the production of defense-associated reactive oxygen species. Moreover, six of these effectors, including the truncated versions of HopAA1 and HopAZ1 encoded by NCPPB 3335, suppressed callose deposition. The expression of HopAZ1 and HopBL1 by functionally effectorless P. syringae pv. tomato DC3000D28E inhibited the hypersensitive response in tobacco and, additionally, expression of HopBL2 by this strain significantly increased its competitiveness in N. benthamiana. DNA sequences encoding HopBL1 and HopBL2 were uniquely detected in a collection of 31 P. savastanoi pv. savastanoi strains and other P. syringae strains isolated from woody hosts, suggesting a relevant role of these two effectors in bacterial interactions with olive and other woody plants.
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Bao Z, Stodghill PV, Myers CR, Lam H, Wei HL, Chakravarthy S, Kvitko BH, Collmer A, Cartinhour SW, Schweitzer P, Swingle B. Genomic plasticity enables phenotypic variation of Pseudomonas syringae pv. tomato DC3000. PLoS One 2014; 9:e86628. [PMID: 24516535 PMCID: PMC3916326 DOI: 10.1371/journal.pone.0086628] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/16/2013] [Indexed: 11/18/2022] Open
Abstract
Whole genome sequencing revealed the presence of a genomic anomaly in the region of 4.7 to 4.9 Mb of the Pseudomonas syringae pv. tomato (Pst) DC3000 genome. The average read depth coverage of Pst DC3000 whole genome sequencing results suggested that a 165 kb segment of the chromosome had doubled in copy number. Further analysis confirmed the 165 kb duplication and that the two copies were arranged as a direct tandem repeat. Examination of the corresponding locus in Pst NCPPB1106, the parent strain of Pst DC3000, suggested that the 165 kb duplication most likely formed after the two strains diverged via transposition of an ISPsy5 insertion sequence (IS) followed by unequal crossing over between ISPsy5 elements at each end of the duplicated region. Deletion of one copy of the 165 kb region demonstrated that the duplication facilitated enhanced growth in some culture conditions, but did not affect pathogenic growth in host tomato plants. These types of chromosomal structures are predicted to be unstable and we have observed resolution of the 165 kb duplication to single copy and its subsequent re-duplication. These data demonstrate the role of IS elements in recombination events that facilitate genomic reorganization in P. syringae.
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Affiliation(s)
- Zhongmeng Bao
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Paul V. Stodghill
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Christopher R. Myers
- Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York, United States of America
| | - Hanh Lam
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Suma Chakravarthy
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Brian H. Kvitko
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, United States of America
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Samuel W. Cartinhour
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Peter Schweitzer
- Biotechnology Resource Center, Cornell University, Ithaca, New York, United States of America
| | - Bryan Swingle
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
- * E-mail:
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Tampakaki AP. Commonalities and differences of T3SSs in rhizobia and plant pathogenic bacteria. FRONTIERS IN PLANT SCIENCE 2014; 5:114. [PMID: 24723933 PMCID: PMC3973906 DOI: 10.3389/fpls.2014.00114] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/11/2014] [Indexed: 05/19/2023]
Abstract
Plant pathogenic bacteria and rhizobia infect higher plants albeit the interactions with their hosts are principally distinct and lead to completely different phenotypic outcomes, either pathogenic or mutualistic, respectively. Bacterial protein delivery to plant host plays an essential role in determining the phenotypic outcome of plant-bacteria interactions. The involvement of type III secretion systems (T3SSs) in mediating animal- and plant-pathogen interactions was discovered in the mid-80's and is now recognized as a multiprotein nanomachine dedicated to trans-kingdom movement of effector proteins. The discovery of T3SS in bacteria with symbiotic lifestyles broadened its role beyond virulence. In most T3SS-positive bacterial pathogens, virulence is largely dependent on functional T3SSs, while in rhizobia the system is dispensable for nodulation and can affect positively or negatively the mutualistic associations with their hosts. This review focuses on recent comparative genome analyses in plant pathogens and rhizobia that uncovered similarities and variations among T3SSs in their genetic organization, regulatory networks and type III secreted proteins and discusses the evolutionary adaptations of T3SSs and type III secreted proteins that might account for the distinguishable phenotypes and host range characteristics of plant pathogens and symbionts.
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Affiliation(s)
- Anastasia P. Tampakaki
- *Correspondence: Anastasia P. Tampakaki, Laboratory of General and Agricultural Microbiology, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, Votanikos, 11855, Athens, Greece e-mail:
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Schumacher J, Waite CJ, Bennett MH, Perez MF, Shethi K, Buck M. Differential secretome analysis of Pseudomonas syringae pv tomato using gel-free MS proteomics. FRONTIERS IN PLANT SCIENCE 2014; 5:242. [PMID: 25071788 PMCID: PMC4082315 DOI: 10.3389/fpls.2014.00242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 05/12/2014] [Indexed: 05/03/2023]
Abstract
The plant pathogen Pseudomonas syringae pv.tomato (DC3000) causes virulence by delivering effector proteins into host plant cells through its type three secretion system (T3SS). In response to the plant environment DC3000 expresses hypersensitive response and pathogenicity genes (hrp). Pathogenesis depends on the ability of the pathogen to manipulate the plant metabolism and to inhibit plant immunity, which depends to a large degree on the plant's capacity to recognize both pathogen and microbial determinants (PAMP/MAMP-triggered immunity). We have developed and employed MS-based shotgun and targeted proteomics to (i) elucidate the extracellular and secretome composition of DC3000 and (ii) evaluate temporal features of the assembly of the T3SS and the secretion process together with its dependence of pH. The proteomic screen, under hrp inducing in vitro conditions, of extracellular and cytoplasmatic fractions indicated the segregated presence of not only T3SS implicated proteins such as HopP1, HrpK1, HrpA1 and AvrPto1, but also of proteins not usually associated with the T3SS or with pathogenicity. Using multiple reaction monitoring MS (MRM-MS) to quantify HrpA1 and AvrPto1, we found that HrpA1 is rapidly expressed, at a strict pH-dependent rate and is post-translationally processed extracellularly. These features appear to not interfere with rapid AvrPto1 expression and secretion but may suggest some temporal post-translational regulatory mechanism of the T3SS assembly. The high specificity and sensitivity of the MRM-MS approach should provide a powerful tool to measure secretion and translocation in infected tissues.
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Affiliation(s)
- Jörg Schumacher
- *Correspondence: Jörg Schumacher and Martin Buck, Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, SW7 2AZ, UK e-mail: ;
| | | | | | | | | | - Martin Buck
- *Correspondence: Jörg Schumacher and Martin Buck, Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London, SW7 2AZ, UK e-mail: ;
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