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Deb S, Madhavan VN, Gokulan CG, Patel HK, Sonti RV. Arms and ammunitions: effectors at the interface of rice and it's pathogens and pests. RICE (NEW YORK, N.Y.) 2021; 14:94. [PMID: 34792681 PMCID: PMC8602583 DOI: 10.1186/s12284-021-00534-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
The plant immune system has evolved to resist attack by pathogens and pests. However, successful phytopathogens deliver effector proteins into plant cells where they hijack the host cellular machinery to suppress the plant immune responses and promote infection. This manipulation of the host cellular pathways is done by the pathogen using various enzymatic activities, protein- DNA or protein- protein interactions. Rice is one the major economically important crops and its yield is affected by several pathogens and pests. In this review, we summarize the various effectors at the plant- pathogen/ pest interface for the major pathogens and pests of rice, specifically, on the mode of action and target genes of the effector proteins. We then compare this across the major rice pathogens and pests in a bid to understand probable conserved pathways which are under attack from pathogens and pests in rice. This analysis highlights conserved patterns of effector action, as well as unique host pathways targeted by the pathogens and pests.
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Affiliation(s)
- Sohini Deb
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
- Present Address: Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | | | - C. G. Gokulan
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
| | - Hitendra K. Patel
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
| | - Ramesh V. Sonti
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, 500007 India
- Present Address: Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507 India
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Shah SMA, Haq F, Ma W, Xu X, Wang S, Xu Z, Zou L, Zhu B, Chen G. Tal1 NXtc01 in Xanthomonas translucens pv. cerealis Contributes to Virulence in Bacterial Leaf Streak of Wheat. Front Microbiol 2019; 10:2040. [PMID: 31551976 PMCID: PMC6737349 DOI: 10.3389/fmicb.2019.02040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/19/2019] [Indexed: 12/21/2022] Open
Abstract
Xanthomonas translucens pv. cerealis (Xtc) causes bacterial leaf streak (BLS) of important cereal crops, including wheat (Triticum aestivum) and barley (Hordeum vulgare). Transcription activator-like effectors (TALEs) play vital roles in many plant diseases caused by Xanthomonas spp., however, TALEs have not been previously characterized in Xtc. In this study, the whole genome of NXtc01, a virulent strain of Xtc from Xinjiang, China, was sequenced and compared with genomes of other Xanthomonas spp. Xtc NXtc01 consists of a single 4,622,298 bp chromosome that encodes 4,004 genes. Alignment of the NXtc01 sequence with the draft genome of Xtc strain CFBP 2541 (United States) revealed a single giant inversion and differences in the location of two tal genes, which were designated tal1 and tal2. In NXtc01, both tal genes are located on the chromosome, whereas tal2 is plasmid-encoded in CFBP 2541. The repeat variable diresidues (RVDs) at the 12th and 13th sites within Tal2 repeat units were identical in both strains, whereas Tal1 showed differences in the third RVD. Xtc NXtc01 and CFBP 2541 encoded 35 and 33 non-TALE type III effectors (T3Es), respectively. tal1, tal2, and tal-free deletion mutants of Xtc NXtc01 were constructed and evaluated for virulence. The tal1 and tal-free deletion mutants were impaired with respect to symptom development and growth in wheat, suggesting that tal1 is a virulence factor in NXtc01. This was confirmed in gain-of-function experiments that showed the introduction of tal1, but not tal2, restored virulence to the tal-free mutant. Furthermore, we generated a hrcC deletion mutant of NXtc01; the hrcC mutant was non-pathogenic on wheat and unable to elicit a hypersensitive response in the non-host Nicotiana benthamiana. Our data provide a platform for exploring the roles of both TALEs and non-TALEs in promoting BLS on wheat.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Sai Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Zhu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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3
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Effector Gene xopAE of Xanthomonas euvesicatoria 85-10 Is Part of an Operon and Encodes an E3 Ubiquitin Ligase. J Bacteriol 2018; 200:JB.00104-18. [PMID: 29784884 DOI: 10.1128/jb.00104-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/13/2018] [Indexed: 01/08/2023] Open
Abstract
The type III effector XopAE from the Xanthomonas euvesicatoria strain 85-10 was previously shown to inhibit plant immunity and enhance pathogen-induced disease symptoms. Evolutionary analysis of 60 xopAE alleles (AEal) revealed that the xopAE locus is conserved in multiple Xanthomonas species. The majority of xopAE alleles (55 out of 60) comprise a single open reading frame (ORF) (xopAE), while in 5 alleles, including AEal 37 of the X. euvesicatoria 85-10 strain, a frameshift splits the locus into two ORFs (hpaF and a truncated xopAE). To test whether the second ORF of AEal 37 (xopAE85-10 ) is translated, we examined expression of yellow fluorescent protein (YFP) fused downstream to truncated or mutant forms of the locus in Xanthomonas bacteria. YFP fluorescence was detected at maximal levels when the reporter was in proximity to an internal ribosome binding site upstream of a rare ATT start codon in the xopAE85-10 ORF but was severely reduced when these elements were abolished. In agreement with the notion that xopAE85-10 is a functional gene, its protein product was translocated into plant cells by the type III secretion system, and translocation was dependent on its upstream ORF, hpaF Homology modeling predicted that XopAE85-10 contains an E3 ligase XL box domain at the C terminus, and in vitro assays demonstrated that this domain displays monoubiquitination activity. Remarkably, the XL box was essential for XopAE85-10 to inhibit pathogen-associated molecular pattern (PAMP)-induced gene expression in Arabidopsis protoplasts. Together, these results indicate that the xopAE85-10 gene resides in a functional operon, which utilizes the alternative start codon ATT and encodes a novel XL box E3 ligase.IMPORTANCEXanthomonas bacteria utilize a type III secretion system to cause disease in many crops. This study provides insights into the evolution, translocation, and biochemical function of the XopAE type III secreted effector, contributing to the understanding of Xanthomonas-host interactions. We establish XopAE as a core effector of seven Xanthomonas species and elucidate the evolution of the Xanthomonas euvesicatoriaxopAE locus, which contains an operon encoding a truncated effector. Our findings indicate that this operon evolved from the split of a multidomain gene into two ORFs that conserved the original domain function. Analysis of xopAE85-10 translation provides the first evidence for translation initiation from an ATT codon in Xanthomonas Our data demonstrate that XopAE85-10 is an XL box E3 ubiquitin ligase and provide insights into the structure and function of this effector family.
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Long J, Song C, Yan F, Zhou J, Zhou H, Yang B. Non-TAL Effectors From Xanthomonas oryzae pv. oryzae Suppress Peptidoglycan-Triggered MAPK Activation in Rice. FRONTIERS IN PLANT SCIENCE 2018; 9:1857. [PMID: 30631333 PMCID: PMC6315156 DOI: 10.3389/fpls.2018.01857] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/30/2018] [Indexed: 05/12/2023]
Abstract
Xanthomonas oryzae pv. oryzae, the causal pathogen of bacterial blight of rice, depends on its type III secretion system and associated effector proteins to grow and colonize the vascular tissues of rice plants. The type III effectors include a family of closely related transcription activator-like (TAL) effectors and the rest of diverse effectors, so-called non-TAL effectors. Our understanding of non-TAL effectors for pathogenesis in rice blight is still limited. Here we report a feasible method to rapidly detect the activation of mitogen-activated protein kinase pathway in rice mesophyll protoplasts by the X. oryzae pv. oryzae derived peptidoglycan and screen for virulent effectors that can suppress the pathogen-associated molecular pattern triggered immunity (PTI) response. Amongst 17 non-TAL effectors transiently expressed in rice cells, we found that three effectors (XopZ, XopN, and XopV) were able to suppress the peptidoglycan-triggered MAPK activation. The triple mutant of the X. oryzae pv. oryzae strain PXO99A lacking XopZ, XopN, and XopV showed additively reduced virulence. Adding back either of genes restored the virulence of the triple mutant. Our results demonstrate the collective and redundant ability of defense suppression by non-TAL effectors in causing bacterial blight of rice.
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Affiliation(s)
- Juying Long
- Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Education, Nanjing Agricultural University, Nanjing, China
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
| | - Congfeng Song
- Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Education, Nanjing Agricultural University, Nanjing, China
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
| | - Fang Yan
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junhui Zhou
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
| | - Huanbin Zhou
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Huanbin Zhou, Bing Yang,
| | - Bing Yang
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, United States
- Division of Plant Sciences, University of Missouri, Columbia, MO, United States
- Donald Danforth Plant Science Center, St. Louis, MO, United States
- *Correspondence: Huanbin Zhou, Bing Yang,
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5
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Falahi Charkhabi N, Booher NJ, Peng Z, Wang L, Rahimian H, Shams-Bakhsh M, Liu Z, Liu S, White FF, Bogdanove AJ. Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat. Front Microbiol 2017; 8:1488. [PMID: 28848509 PMCID: PMC5554336 DOI: 10.3389/fmicb.2017.01488] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/24/2017] [Indexed: 12/31/2022] Open
Abstract
Bacterial leaf streak caused by Xanthomonas translucens pv. undulosa (Xtu) is an important disease of wheat (Triticum aestivum) and barley (Hordeum vulgare) worldwide. Transcription activator-like effectors (TALEs) play determinative roles in many of the plant diseases caused by the different species and pathovars of Xanthomonas, but their role in this disease has not been characterized. ICMP11055 is a highly virulent Xtu strain from Iran. The aim of this study was to better understand genetic diversity of Xtu and to assess the role of TALEs in bacterial leaf streak of wheat by comparing the genome of this strain to the recently completely sequenced genome of a U.S. Xtu strain, and to several other draft X. translucens genomes, and by carrying out mutational analyses of the TALE (tal) genes the Iranian strain might harbor. The ICMP11055 genome, including its repeat-rich tal genes, was completely sequenced using single molecule, real-time technology (Pacific Biosciences). It consists of a single circular chromosome of 4,561,583 bp, containing 3,953 genes. Whole genome alignment with the genome of the United States Xtu strain XT4699 showed two major re-arrangements, nine genomic regions unique to ICMP11055, and one region unique to XT4699. ICMP110055 harbors 26 non-TALE type III effector genes and seven tal genes, compared to 25 and eight for XT4699. The tal genes occur singly or in pairs across five scattered loci. Four are identical to tal genes in XT4699. In addition to common repeat-variable diresidues (RVDs), the tal genes of ICMP11055, like those of XT4699, encode several RVDs rarely observed in Xanthomonas, including KG, NF, Y∗, YD, and YK. Insertion and deletion mutagenesis of ICMP11055 tal genes followed by genetic complementation analysis in wheat cv. Chinese Spring revealed that Tal2 and Tal4b of ICMP11055 each contribute individually to the extent of disease caused by this strain. A largely conserved ortholog of tal2 is present in XT4699, but for tal4b, only a gene with partial, fragmented RVD sequence similarity can be found. Our results lay the foundation for identification of important host genes activated by Xtu TALEs as targets for the development of disease resistant varieties.
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Affiliation(s)
- Nargues Falahi Charkhabi
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States.,Department of Plant Pathology, Tarbiat Modares UniversityTehran, Iran
| | - Nicholas J Booher
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Zhao Peng
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States.,Department of Plant Pathology, University of Florida, GainesvilleFL, United States
| | - Li Wang
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Heshmat Rahimian
- Department of Plant Protection, Sari Agricultural Science and Natural Resources UniversitySari, Iran
| | | | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, FargoND, United States
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States
| | - Frank F White
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States.,Department of Plant Pathology, University of Florida, GainesvilleFL, United States
| | - Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
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6
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Showmaker KC, Arick MA, Hsu CY, Martin BE, Wang X, Jia J, Wubben MJ, Nichols RL, Allen TW, Peterson DG, Lu SE. The genome of the cotton bacterial blight pathogen Xanthomonas citri pv. malvacearum strain MSCT1. Stand Genomic Sci 2017; 12:42. [PMID: 28770027 PMCID: PMC5525278 DOI: 10.1186/s40793-017-0253-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/12/2017] [Indexed: 12/15/2022] Open
Abstract
Xanthomonas citri pv. malvacearum is a major pathogen of cotton, Gossypium hirsutum L.. In this study we report the complete genome of the X. citri pv. malvacearum strain MSCT1 assembled from long read DNA sequencing technology. The MSCT1 genome is the first X. citri pv. malvacearum genome with complete coding regions for X. citri pv. malvacearum transcriptional activator-like effectors. In addition functional and structural annotations are presented in this study that will provide a foundation for future pathogenesis studies with MSCT1.
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Affiliation(s)
- Kurt C Showmaker
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762 USA.,Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 USA
| | - Mark A Arick
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762 USA
| | - Chuan-Yu Hsu
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762 USA
| | - Brigitte E Martin
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762 USA
| | - Xiaoqiang Wang
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 USA
| | - Jiayuan Jia
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 USA
| | - Martin J Wubben
- USDA-ARS, Crop Science Research Lab, Genetics and Sustainable Agriculture Research Unit, Mississippi State, MS 39762 USA
| | | | - Tom W Allen
- Mississippi State University, Delta Research and Extension Center, 82 Stoneville Rd, Stoneville, MS 38776 USA
| | - Daniel G Peterson
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762 USA.,Department of Plant & Soil Sciences, Mississippi State University, Mississippi State, MS 39762 USA
| | - Shi-En Lu
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 USA
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7
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Gupta MK, Nathawat R, Sinha D, Haque AS, Sankaranarayanan R, Sonti RV. Mutations in the Predicted Active Site of Xanthomonas oryzae pv. oryzae XopQ Differentially Affect Virulence, Suppression of Host Innate Immunity, and Induction of the HR in a Nonhost Plant. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:195-206. [PMID: 25353365 DOI: 10.1094/mpmi-09-14-0288-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, secretes a number of effectors through a type 3 secretion system. One of these effectors, called XopQ, is required for virulence and suppression of rice innate immune responses induced by the plant cell-wall-degrading enzyme lipase/esterase A (LipA). Bioinformatic analysis suggested that XopQ is homologous to inosine-uridine nucleoside hydrolases (NH). A structural model of XopQ with the protozoan Crithidia fasciculata purine NH suggested that D116 and Y279 are potential active site residues. X. oryzae pv. oryzae xopQ mutants (xopQ-/pHM1::xopQD116A and xopQ-/pHM1::xopQY279A) show reduced virulence on rice compared with xopQ-/pHM1::xopQ. The two predicted XopQ active site mutants (xopQ-/pHM1::xopQD116A and xopQ-/pHM1::xopQY279A) exhibit a reduced hypersensitive response (HR) on Nicotiana benthamiana, a nonhost. However, Arabidopsis lines expressing either xopQ or xopQY279A are equally proficient at suppression of LipA-induced callose deposition. Purified XopQ does not show NH activity on standard nucleoside substrates but exhibits ribose hydrolase activity on the nucleoside substrate analogue 4-nitrophenyl β-D-ribofuranoside. The D116A and Y279A mutations cause a reduction in biochemical activity. These results indicate that mutations in the predicted active site of XopQ affect virulence and induction of the HR but do not affect suppression of innate immunity.
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8
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Liu H, Chang Q, Feng W, Zhang B, Wu T, Li N, Yao F, Ding X, Chu Z. Domain dissection of AvrRxo1 for suppressor, avirulence and cytotoxicity functions. PLoS One 2014; 9:e113875. [PMID: 25437277 PMCID: PMC4250038 DOI: 10.1371/journal.pone.0113875] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/01/2014] [Indexed: 12/27/2022] Open
Abstract
AvrRxo1, a type III effector from Xanthomonas oryzae pv. oryzicola (Xoc) which causes bacterial leaf streak (BLS) in rice, can be recognised by non-host resistance protein Rxo1. It triggers a hypersensitive response (HR) in maize. Little is known regarding the virulence function of AvrRxo1. In this study, we determined that AvrRxo1 is able to suppress the HR caused by the non-host resistance recognition of Xanthomonas oryzae pv. oryzae (Xoo) by Nicotiana benthamiana. It is toxic, inducing cell death from transient expression in N. benthamiana, as well as in yeast. Among the four AvrRxo1 alleles from different Xoc strains, we concluded that the toxicity is abolished by a single amino acid substitution at residue 344 in two AvrRxo1 alleles. A series of truncations from the carboxyl terminus (C-terminus) indicate that the complete C-terminus of AvrRxo1 plays an essential role as a suppressor or cytotoxic protein. The C-terminus was also required for the avirulence function, but the last two residues were not necessary. The first 52 amino acids of N-terminus are unessential for toxicity. Point mutagenesis experiments indicate that the ATP/GTP binding site motif A is required for all three functions of AvrRxo1, and NLS is required for both the avirulence and the suppression of non-host resistance. The putative thiol protease site is only required for the cytotoxicity function. These results determine that AvrRxo1 plays a role in the complex interaction with host proteins after delivery into plant cells.
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Affiliation(s)
- Haifeng Liu
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Qingle Chang
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Wenjie Feng
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Baogang Zhang
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Tao Wu
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Ning Li
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Fangyin Yao
- Biotechnology Research Center, Shandong Academy of Agricultural Science, Jinan, Shandong, PR China
| | - Xinhua Ding
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
| | - Zhaohui Chu
- State Key Laboratory of Crop Biology, Shandong Provincial Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai an, Shandong, PR China
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9
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Sinha D, Gupta MK, Patel HK, Ranjan A, Sonti RV. Cell wall degrading enzyme induced rice innate immune responses are suppressed by the type 3 secretion system effectors XopN, XopQ, XopX and XopZ of Xanthomonas oryzae pv. oryzae. PLoS One 2013; 8:e75867. [PMID: 24086651 PMCID: PMC3784402 DOI: 10.1371/journal.pone.0075867] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 08/16/2013] [Indexed: 12/12/2022] Open
Abstract
Innate immune responses are induced in plants and animals through perception of Damage Associated Molecular Patterns. These immune responses are suppressed by pathogens during infection. A number of studies have focussed on identifying functions of plant pathogenic bacteria that are involved in suppression of Pathogen Associated Molecular Pattern induced immune responses. In comparison, there is very little information on functions used by plant pathogens to suppress Damage Associated Molecular Pattern induced immune responses. Xanthomonasoryzae pv. oryzae, a gram negative bacterial pathogen of rice, secretes hydrolytic enzymes such as LipA (Lipase/Esterase) that damage rice cell walls and induce innate immune responses. Here, we show that Agrobacterium mediated transient transfer of the gene for XopN, a X. oryzae pv. oryzae type 3 secretion (T3S) system effector, results in suppression of rice innate immune responses induced by LipA. A xopN- mutant of X. oryzae pv. oryzae retains the ability to suppress these innate immune responses indicating the presence of other functionally redundant proteins. In transient transfer assays, we have assessed the ability of 15 other X. oryzae pv. oryzae T3S secreted effectors to suppress rice innate immune responses. Amongst these proteins, XopQ, XopX and XopZ are suppressors of LipA induced innate immune responses. A mutation in any one of the xopN, xopQ, xopX or xopZ genes causes partial virulence deficiency while a xopN- xopX- double mutant exhibits a greater virulence deficiency. A xopN- xopQ- xopX- xopZ- quadruple mutant of X. oryzae pv. oryzae induces callose deposition, an innate immune response, similar to a X. oryzae pv. oryzae T3S- mutant in rice leaves. Overall, these results indicate that multiple T3S secreted proteins of X. oryzae pv. oryzae can suppress cell wall damage induced rice innate immune responses.
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Affiliation(s)
- Dipanwita Sinha
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India
| | - Mahesh Kumar Gupta
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India
| | - Hitendra Kumar Patel
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India
| | - Ashish Ranjan
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India
| | - Ramesh V. Sonti
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India
- * E-mail:
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10
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Cheong H, Kim CY, Jeon JS, Lee BM, Sun Moon J, Hwang I. Xanthomonas oryzae pv. oryzae type III effector XopN targets OsVOZ2 and a putative thiamine synthase as a virulence factor in rice. PLoS One 2013; 8:e73346. [PMID: 24019919 PMCID: PMC3760903 DOI: 10.1371/journal.pone.0073346] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/18/2013] [Indexed: 01/13/2023] Open
Abstract
Xanthomonasoryzae pv. oryzae (Xoo) is spread systemically through the xylem tissue and causes bacterial blight in rice. We evaluated the roles of Xanthomonas outer proteins (Xop) in the Xoo strain KXO85 in a Japonica-type rice cultivar, Dongjin. Five xop gene knockout mutants (xopQKXO85, xopXKXO85, xopP1KXO85, xopP2KXO85, and xopNKXO85) were generated by EZ-Tn5 mutagenesis, and their virulence was assessed in 3-month-old rice leaves. Among these mutants, the xopNKXO85 mutant appeared to be less virulent than the wild-type KXO85; however, the difference was not statistically significant. In contrast, the xopNKXO85 mutant exhibited significantly less virulence in flag leaves after flowering than the wild-type KXO85. These observations indicate that the roles of Xop in Xoo virulence are dependent on leaf stage. We chose the xopN gene for further characterization because the xopNKXO85 mutant showed the greatest influence on virulence. We confirmed that XopNKXO85 is translocated into rice cells, and its gene expression is positively regulated by HrpX. Two rice proteins, OsVOZ2 and a putative thiamine synthase (OsXNP), were identified as targets of XopNKXO85 by yeast two-hybrid screening. Interactions between XopNKXO85 and OsVOZ2 and OsXNP were further confirmed in planta by bimolecular fluorescence complementation and in vivo pull-down assays. To investigate the roles of OsVOZ2 in interactions between rice and Xoo, we evaluated the virulence of the wild-type KXO85 and xopNKXO85 mutant in the OsVOZ2 mutant line PFG_3A-07565 of Dongjin. The wild-type KXO85 and xopNKXO85 mutant were significantly less virulent in the mutant rice line. These results indicate that XopNKXO85 and OsVOZ2 play important roles both individually and together for Xoo virulence in rice.
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Affiliation(s)
- Hoon Cheong
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Chi-Yeol Kim
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Jong-Seong Jeon
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Byoung-Moo Lee
- National Academy of Agricultural Science, Rural Development Administration, Suwon, Korea
| | - Jae Sun Moon
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Ingyu Hwang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
- * E-mail:
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