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Rymaszewski W, Giska F, Piechocki MA, Zembek PB, Krzymowska M. Formation of HopQ1:14-3-3 complex in the host cytoplasm modulates nuclear import rate of Pseudomonas syringae effector in Nicotiana benthamiana cells. FRONTIERS IN PLANT SCIENCE 2024; 15:1335830. [PMID: 38501137 PMCID: PMC10944878 DOI: 10.3389/fpls.2024.1335830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/09/2024] [Indexed: 03/20/2024]
Abstract
HopQ1, a type three effector from Pseudomonas syringae upon phosphorylation coopts plant 14-3-3 proteins to control its stability and subcellular localization. Mass spectrometry of the cytoplasm-restricted effector revealed that HopQ1 already in this subcellular compartment undergoes phosphorylation at serine 51 within the canonical 14-3-3 binding motif and within the second putative 14-3-3 binding site, 24RTPSES29. Our analyses revealed that the stoichiometry of the HopQ1:14-3-3a complex is 1:2 indicating that both binding sites of HopQ1 are involved in the interaction. Notably, 24RTPSES29 comprises a putative nuclear translocation signal (NTS). Although a peptide containing NTS mediates nuclear import of a Cargo protein suggesting its role in the nuclear trafficking of HopQ1, a deletion of 25TPS27 does not change HopQ1 distribution. In contrast, elimination of 14-3-3 binding site, accelerates nuclear trafficking the effector. Collectively, we show that formation of the HopQ1:14-3-3 complex occurs in the host cytoplasm and slows down the effector translocation into the nucleus. These results provide a mechanism that maintains the proper nucleocytoplasmic partitioning of HopQ1, and at the same time is responsible for the relocation of 14-3-3s from the nucleus to cytoplasm in the presence of the effector.
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Affiliation(s)
| | | | | | | | - Magdalena Krzymowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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2
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Pangenomic analysis reveals plant NAD + manipulation as an important virulence activity of bacterial pathogen effectors. Proc Natl Acad Sci U S A 2023; 120:e2217114120. [PMID: 36753463 PMCID: PMC9963460 DOI: 10.1073/pnas.2217114120] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) has emerged as a key component in prokaryotic and eukaryotic immune systems. The recent discovery that Toll/interleukin-1 receptor (TIR) proteins function as NAD+ hydrolases (NADase) links NAD+-derived small molecules with immune signaling. We investigated pathogen manipulation of host NAD+ metabolism as a virulence strategy. Using the pangenome of the model bacterial pathogen Pseudomonas syringae, we conducted a structure-based similarity search from 35,000 orthogroups for type III effectors (T3Es) with potential NADase activity. Thirteen T3Es, including five newly identified candidates, were identified that possess domain(s) characteristic of seven NAD+-hydrolyzing enzyme families. Most Pseudomonas syringae strains that depend on the type III secretion system to cause disease, encode at least one NAD+-manipulating T3E, and many have several. We experimentally confirmed the type III-dependent secretion of a novel T3E, named HopBY, which shows structural similarity to both TIR and adenosine diphosphate ribose (ADPR) cyclase. Homologs of HopBY were predicted to be type VI effectors in diverse bacterial species, indicating potential recruitment of this activity by microbial proteins secreted during various interspecies interactions. HopBY efficiently hydrolyzes NAD+ and specifically produces 2'cADPR, which can also be produced by TIR immune receptors of plants and by other bacteria. Intriguingly, this effector promoted bacterial virulence, indicating that 2'cADPR may not be the signaling molecule that directly initiates immunity. This study highlights a host-pathogen battleground centered around NAD+ metabolism and provides insight into the NAD+-derived molecules involved in plant immunity.
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3
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Reyes Caldas PA, Zhu J, Breakspear A, Thapa SP, Toruño TY, Perilla-Henao LM, Casteel C, Faulkner CR, Coaker G. Effectors from a Bacterial Vector-Borne Pathogen Exhibit Diverse Subcellular Localization, Expression Profiles, and Manipulation of Plant Defense. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:1067-1080. [PMID: 35952362 PMCID: PMC9844206 DOI: 10.1094/mpmi-05-22-0114-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Climate change is predicted to increase the prevalence of vector-borne disease due to expansion of insect populations. 'Candidatus Liberibacter solanacearum' is a phloem-limited pathogen associated with multiple economically important diseases in solanaceous crops. Little is known about the strategies and pathogenicity factors 'Ca. L. solanacearum' uses to colonize its vector and host. We determined the 'Ca. L. solanacearum' effector repertoire by predicting proteins secreted by the general secretory pathway across four different 'Ca. L. solanacearum' haplotypes, investigated effector localization in planta, and profiled effector expression in the vector and host. The localization of 'Ca. L. solanacearum' effectors in Nicotiana spp. revealed diverse eukaryotic subcellular targets. The majority of tested effectors were unable to suppress plant immune responses, indicating they possess unique activities. Expression profiling in tomato and the psyllid Bactericera cockerelli indicated 'Ca. L. solanacearum' differentially interacts with its host and vector and can switch effector expression in response to these environments. This study reveals 'Ca. L. solanacearum' effectors possess complex expression patterns, target diverse host organelles and the majority are unable to suppress host immune responses. A mechanistic understanding of 'Ca. L. solanacearum' effector function will reveal novel targets and provide insight into phloem biology. [Formula: see text] Copyright © 2022 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)
| | - Jie Zhu
- Plant Pathology Department, University of California, Davis, CA, U.S.A
| | | | - Shree P. Thapa
- Plant Pathology Department, University of California, Davis, CA, U.S.A
| | - Tania Y. Toruño
- Plant Pathology Department, University of California, Davis, CA, U.S.A
- Rijk Zwaan Breeding B.V, Burgemeester Crezéelaan 40, De Lier, 2678 KX, The Netherlands
| | | | - Clare Casteel
- Plant Pathology Department, University of California, Davis, CA, U.S.A
- School of Integrative Plant Science, Plant-Microbe Biology and Plant Pathology Section, Cornell University, Ithaca, NY, U.S.A
| | | | - Gitta Coaker
- Plant Pathology Department, University of California, Davis, CA, U.S.A
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4
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Degano M. Structure, Oligomerization and Activity Modulation in N-Ribohydrolases. Int J Mol Sci 2022; 23:ijms23052576. [PMID: 35269719 PMCID: PMC8910321 DOI: 10.3390/ijms23052576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 12/15/2022] Open
Abstract
Enzymes catalyzing the hydrolysis of the N-glycosidic bond in nucleosides and other ribosides (N-ribohydrolases, NHs) with diverse substrate specificities are found in all kingdoms of life. While the overall NH fold is highly conserved, limited substitutions and insertions can account for differences in substrate selection, catalytic efficiency, and distinct structural features. The NH structural module is also employed in monomeric proteins devoid of enzymatic activity with different physiological roles. The homo-oligomeric quaternary structure of active NHs parallels the different catalytic strategies used by each isozyme, while providing a buttressing effect to maintain the active site geometry and allow the conformational changes required for catalysis. The unique features of the NH catalytic strategy and structure make these proteins attractive targets for diverse therapeutic goals in different diseases.
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Affiliation(s)
- Massimo Degano
- Biocrystallography Unit, Division of Immunology, Transplantation, and Infectious Diseases, IRCCS Scientific Institute San Raffaele, via Olgettina 60, 20132 Milano, Italy;
- Università Vita-Salute San Raffaele, via Olgettina 58, 20132 Milano, Italy
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5
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Schreiber KJ, Chau-Ly IJ, Lewis JD. What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins. Microorganisms 2021; 9:1029. [PMID: 34064647 PMCID: PMC8150971 DOI: 10.3390/microorganisms9051029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 01/05/2023] Open
Abstract
Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.
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Affiliation(s)
- Karl J. Schreiber
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Ilea J. Chau-Ly
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
| | - Jennifer D. Lewis
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94710, USA; (K.J.S.); (I.J.C.-L.)
- Plant Gene Expression Center, United States Department of Agriculture, University of California, Berkeley, CA 94710, USA
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6
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NOD-like receptor-mediated plant immunity: from structure to cell death. Nat Rev Immunol 2020; 21:305-318. [PMID: 33293618 DOI: 10.1038/s41577-020-00473-z] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2020] [Indexed: 12/25/2022]
Abstract
Animal and plant immune systems use intracellular nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) to detect pathogens, resulting in the activation of immune responses that are often associated with localized host cell death. Whereas vertebrate NLRs detect evolutionarily conserved molecular patterns and have undergone comparatively little copy number expansion, plant NLRs detect virulence factors that have often diversified in plant pathogen populations, and thus plant NLRs have been subject to parallel diversification. Plant NLRs sense the presence of virulence factors with enzymatic virulence activity often indirectly through their modification of host target proteins. By contrast, phytopathogenic virulence factors without enzymatic activity are usually recognized by NLRs directly by their structure. Structural and biochemical analyses have shown that both indirect and direct recognition of plant pathogens trigger the oligomerization of plant NLRs into active complexes. Assembly into three-layered ring-like structures has emerged as a common principle of NLR activation in plants and animals, but with distinct amino-terminal domains initiating different signalling pathways. Collectively, these analyses point to host cell membranes as a convergence point for activated plant NLRs and the disruption of cellular ion homeostasis as a possible major factor in NLR-triggered cell death signalling.
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7
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Martin R, Qi T, Zhang H, Liu F, King M, Toth C, Nogales E, Staskawicz BJ. Structure of the activated ROQ1 resistosome directly recognizing the pathogen effector XopQ. Science 2020; 370:eabd9993. [PMID: 33273074 PMCID: PMC7995448 DOI: 10.1126/science.abd9993] [Citation(s) in RCA: 233] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/19/2020] [Indexed: 12/29/2022]
Abstract
Plants and animals detect pathogen infection using intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) that directly or indirectly recognize pathogen effectors and activate an immune response. How effector sensing triggers NLR activation remains poorly understood. Here we describe the 3.8-angstrom-resolution cryo-electron microscopy structure of the activated ROQ1 (recognition of XopQ 1), an NLR native to Nicotiana benthamiana with a Toll-like interleukin-1 receptor (TIR) domain bound to the Xanthomonas euvesicatoria effector XopQ (Xanthomonas outer protein Q). ROQ1 directly binds to both the predicted active site and surface residues of XopQ while forming a tetrameric resistosome that brings together the TIR domains for downstream immune signaling. Our results suggest a mechanism for the direct recognition of effectors by NLRs leading to the oligomerization-dependent activation of a plant resistosome and signaling by the TIR domain.
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Affiliation(s)
- Raoul Martin
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
- QB3, University of California, Berkeley, CA 94720, USA
| | - Tiancong Qi
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA
| | - Haibo Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Furong Liu
- Innovative Genomics Institute, University of California, Berkeley, CA 94720 USA
| | - Miles King
- Innovative Genomics Institute, University of California, Berkeley, CA 94720 USA
| | - Claire Toth
- Department of Molecular and Cellular Biology, University of California, Berkeley, CA 94720, USA
| | - Eva Nogales
- QB3, University of California, Berkeley, CA 94720, USA.
- Department of Molecular and Cellular Biology, University of California, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
| | - Brian J Staskawicz
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 USA.
- Innovative Genomics Institute, University of California, Berkeley, CA 94720 USA
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8
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Sun G, Bai S, Guan Y, Wang S, Wang Q, Liu Y, Liu H, Goffinet B, Zhou Y, Paoletti M, Hu X, Haas FB, Fernandez-Pozo N, Czyrt A, Sun H, Rensing SA, Huang J. Are fungi-derived genomic regions related to antagonism towards fungi in mosses? THE NEW PHYTOLOGIST 2020; 228:1169-1175. [PMID: 32578878 DOI: 10.1111/nph.16776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/19/2020] [Indexed: 05/16/2023]
Affiliation(s)
- Guiling Sun
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Shenglong Bai
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Yanlong Guan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Shuanghua Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Qia Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yang Liu
- Fairy Lake Botanical Garden, Chinese Academy of Sciences, Shenzhen, 518004, China
- BGI-Shenzhen, Shenzhen, 518083, China
| | - Huan Liu
- BGI-Shenzhen, Shenzhen, 518083, China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Bernard Goffinet
- Ecology and Evolutionary Biology, University of Connecticut, 75N Eagleville Rd, Storrs, CT, 06269-3043, USA
| | - Yun Zhou
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Mathieu Paoletti
- Laboratoire de Génétique Moléculaire des Champignons, Institut de Biochimie et de Génétique Cellulaires, UMR 5095 CNRS-Université de Bordeaux 2, 1 rue Camille St Saëns, Bordeaux Cedex, 33077, France
| | - Xiangyang Hu
- College of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Fabian B Haas
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Noe Fernandez-Pozo
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Alia Czyrt
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Stefan A Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Jinling Huang
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- Department of Biology, East Carolina University, Greenville, NC, 28590, USA
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9
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Yoon SJ, Park YJ, Kim JS, Lee S, Lee SH, Choi S, Min JK, Choi I, Ryu CM. Pseudomonas syringae evades phagocytosis by animal cells via type III effector-mediated regulation of actin filament plasticity. Environ Microbiol 2018; 20:3980-3991. [PMID: 30251365 DOI: 10.1111/1462-2920.14426] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 01/31/2023]
Abstract
Certain animal and plant pathogenic bacteria have developed virulence factors including effector proteins that enable them to overcome host immunity. A plant pathogen, Pseudomonas syringae pv. tomato (Pto) secretes a large repertoire of effectors via a type III secretory apparatus, thereby suppressing plant immunity. Here, we show that Pto causes sepsis in mice. Surprisingly, the effector HopQ1 disrupted animal phagocytosis by inhibiting actin rearrangement via direct interaction with the LIM domain of the animal target protein LIM kinase, a key regulator of actin polymerization. The results provide novel insight into animal host-plant pathogen interactions. In addition, the current study firstly demonstrates that certain plant pathogenic bacteria such as Pto evade phagocytosis by animal cells due to cross-kingdom suppression of host immunity.
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Affiliation(s)
- Sung-Jin Yoon
- Metabolic Regulation Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea
| | - Young-Jun Park
- Metabolic Regulation Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea.,Department of Functional Genomics, University of Science and Technology (UST), Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Jun-Seob Kim
- Infectious Disease Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea
| | - Soohyun Lee
- Infectious Disease Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea
| | - Sang-Hyun Lee
- Biotherapeutics Translational Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea
| | - Song Choi
- Metabolic Regulation Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea
| | - Jeong-Ki Min
- Biotherapeutics Translational Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea
| | - Inpyo Choi
- Department of Functional Genomics, University of Science and Technology (UST), Yuseong-gu, Daejeon, 34141, Republic of Korea.,Immunotherapy Convergence Research Center, KRIBB, Yuseong-gu, Daejeon, 34141, South Korea
| | - Choong-Min Ryu
- Infectious Disease Research Center, KRIBB, Yuseong-gu, Daejeon 34141, South Korea.,Biosystems and Bioengineering Program, University of Science and Technology (UST), Yuseong-gu, Daejeon, 34141, Republic of Korea
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10
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Piechocki M, Giska F, Koczyk G, Grynberg M, Krzymowska M. An Engineered Distant Homolog of Pseudomonas syringae TTSS Effector From Physcomitrella patens Can Act as a Bacterial Virulence Factor. Front Microbiol 2018; 9:1060. [PMID: 29973916 PMCID: PMC6019455 DOI: 10.3389/fmicb.2018.01060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 05/04/2018] [Indexed: 02/04/2023] Open
Abstract
Pseudomonas syringae pv. phaseolicola is the causative agent of halo blight in common bean (Phaseolus vulgaris). Similar to other pathogenic gram-negative bacteria, it secrets a set of type III effectors into host cells to subvert defense mechanisms. HopQ1 (for Hrp outer protein Q) is one of these type III effectors contributing to virulence of bacteria. Upon delivery into a plant cell, HopQ1 undergoes phosphorylation, binds host 14-3-3 proteins and suppresses defense-related signaling. Some plants however, evolved systems to recognize HopQ1 and respond to its presence and thus to prevent infection. HopQ1 shows homology to Nucleoside Hydrolases (NHs), but it contains a modified calcium binding motif not found in the canonical enzymes. CLuster ANalysis of Sequences (CLANS) revealed that HopQ1 and alike proteins make a distinct group of putative NHs located distantly from the classical enzymes. The HopQ1 – like protein (HLP) group comprises sequences from plant pathogenic bacteria, fungi, and lower plants. Our data suggest that the evolution of HopQ1 homologs in bacteria, fungi, and algae was independent. The location of moss HopQ1 homologs inside the fungal clade indicates a possibility of horizontal gene transfer (HGT) between those taxa. We identified a HLP in the moss Physcomitrella patens. Our experiments show that this protein (referred to as PpHLP) extended by a TTSS signal of HopQ1 promoted P. syringae growth in bean and was recognized by Nicotiana benthamiana immune system. Thus, despite the low sequence similarity to HopQ1 the engineered PpHLP acted as a bacterial virulence factor and displayed similar to HopQ1 virulence properties.
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Affiliation(s)
- Marcin Piechocki
- Institute of Biochemistry and Biophysics (PAS), Laboratory of Plant Pathogenesis, Warsaw, Poland
| | - Fabian Giska
- Institute of Biochemistry and Biophysics (PAS), Laboratory of Plant Pathogenesis, Warsaw, Poland
| | - Grzegorz Koczyk
- Institute of Plant Genetics (PAS), Department of Biometry and Bioinformatics, Poznań, Poland
| | - Marcin Grynberg
- Institute of Biochemistry and Biophysics (PAS), Department of Biophysics, Warsaw, Poland
| | - Magdalena Krzymowska
- Institute of Biochemistry and Biophysics (PAS), Laboratory of Plant Pathogenesis, Warsaw, Poland
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11
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Zembek P, Danilecka A, Hoser R, Eschen-Lippold L, Benicka M, Grech-Baran M, Rymaszewski W, Barymow-Filoniuk I, Morgiewicz K, Kwiatkowski J, Piechocki M, Poznanski J, Lee J, Hennig J, Krzymowska M. Two Strategies of Pseudomonas syringae to Avoid Recognition of the HopQ1 Effector in Nicotiana Species. FRONTIERS IN PLANT SCIENCE 2018; 9:978. [PMID: 30042777 PMCID: PMC6048448 DOI: 10.3389/fpls.2018.00978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/15/2018] [Indexed: 05/18/2023]
Abstract
Pseudomonas syringae employs a battery of type three secretion effectors to subvert plant immune responses. In turn, plants have developed receptors that recognize some of the bacterial effectors. Two strain-specific HopQ1 effector variants (for Hrp outer protein Q) from the pathovars phaseolicola 1448A (Pph) and tomato DC3000 (Pto) showed considerable differences in their ability to evoke disease symptoms in Nicotiana benthamiana. Surprisingly, the variants differ by only six amino acids located mostly in the N-terminal disordered region of HopQ1. We found that the presence of serine 87 and leucine 91 renders PtoHopQ1 susceptible to N-terminal processing by plant proteases. Substitutions at these two positions did not strongly affect PtoHopQ1 virulence properties in a susceptible host but they reduced bacterial growth and accelerated onset of cell death in a resistant host, suggesting that N-terminal mutations rendered PtoHopQ1 susceptible to processing in planta and, thus, represent a mechanism of recognition avoidance. Furthermore, we found that co-expression of HopR1, another effector encoded within the same gene cluster masks HopQ1 recognition in a strain-dependent manner. Together, these data suggest that HopQ1 is under high host-pathogen co-evolutionary selection pressure and P. syringae may have evolved differential effector processing or masking as two independent strategies to evade HopQ1 recognition, thus revealing another level of complexity in plant - microbe interactions.
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Affiliation(s)
- Patrycja Zembek
- Institute of Biochemistry and Biophysics (PAS), Warsaw, Poland
| | | | - Rafał Hoser
- Institute of Biochemistry and Biophysics (PAS), Warsaw, Poland
| | | | - Marta Benicka
- Institute of Biochemistry and Biophysics (PAS), Warsaw, Poland
| | | | | | | | | | | | | | | | - Justin Lee
- Leibniz Institute of Plant Biochemistry, Halle, Germany
| | - Jacek Hennig
- Institute of Biochemistry and Biophysics (PAS), Warsaw, Poland
| | - Magdalena Krzymowska
- Institute of Biochemistry and Biophysics (PAS), Warsaw, Poland
- *Correspondence: Magdalena Krzymowska,
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12
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Rufián JS, Lucía A, Rueda-Blanco J, Zumaquero A, Guevara CM, Ortiz-Martín I, Ruiz-Aldea G, Macho AP, Beuzón CR, Ruiz-Albert J. Suppression of HopZ Effector-Triggered Plant Immunity in a Natural Pathosystem. FRONTIERS IN PLANT SCIENCE 2018; 9:977. [PMID: 30154802 PMCID: PMC6103241 DOI: 10.3389/fpls.2018.00977] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 06/15/2018] [Indexed: 05/13/2023]
Abstract
Many type III-secreted effectors suppress plant defenses, but can also activate effector-triggered immunity (ETI) in resistant backgrounds. ETI suppression has been shown for a number of type III effectors (T3Es) and ETI-suppressing effectors are considered part of the arms race model for the co-evolution of bacterial virulence and plant defense. However, ETI suppression activities have been shown mostly between effectors not being naturally expressed within the same strain. Furthermore, evolution of effector families is rarely explained taking into account that selective pressure against ETI-triggering effectors may be compensated by ETI-suppressing effector(s) translocated by the same strain. The HopZ effector family is one of the most diverse, displaying a high rate of loss and gain of alleles, which reflects opposing selective pressures. HopZ effectors trigger defense responses in a variety of crops and some have been shown to suppress different plant defenses. Mutational changes in the sequence of ETI-triggering effectors have been proposed to result in the avoidance of detection by their respective hosts, in a process called pathoadaptation. We analyze how deleting or overexpressing HopZ1a and HopZ3 affects virulence of HopZ-encoding and non-encoding strains. We find that both effectors trigger immunity in their plant hosts only when delivered from heterologous strains, while immunity is suppressed when delivered from their native strains. We carried out screens aimed at identifying the determinant(s) suppressing HopZ1a-triggered and HopZ3-triggered immunity within their native strains, and identified several effectors displaying suppression of HopZ3-triggered immunity. We propose effector-mediated cross-suppression of ETI as an additional force driving evolution of the HopZ family.
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Affiliation(s)
- José S. Rufián
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ainhoa Lucía
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Javier Rueda-Blanco
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Adela Zumaquero
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Carlos M. Guevara
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Inmaculada Ortiz-Martín
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Gonzalo Ruiz-Aldea
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Carmen R. Beuzón
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Javier Ruiz-Albert
- Departamento Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Málaga, Spain
- *Correspondence: Javier Ruiz-Albert,
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13
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Adlung N, Bonas U. Dissecting virulence function from recognition: cell death suppression in Nicotiana benthamiana by XopQ/HopQ1-family effectors relies on EDS1-dependent immunity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:430-442. [PMID: 28423458 DOI: 10.1111/tpj.13578] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/07/2017] [Accepted: 04/11/2017] [Indexed: 05/27/2023]
Abstract
Many Gram-negative plant pathogenic bacteria express effector proteins of the XopQ/HopQ1 family which are translocated into plant cells via the type III secretion system during infection. In Nicotiana benthamiana, recognition of XopQ/HopQ1 proteins induces an effector-triggered immunity (ETI) reaction which is not associated with strong cell death but renders plants immune against Pseudomonas syringae and Xanthomonas campestris pv. vesicatoria strains. Additionally, XopQ suppresses cell death in N. benthamiana when transiently co-expressed with cell death inducers. Here, we show that representative XopQ/HopQ1 proteins are recognized similarly, likely by a single resistance protein of the TIR-NB-LRR class. Extensive analysis of XopQ derivatives indicates the recognition of structural features. We performed Agrobacterium-mediated protein expression experiments in wild-type and EDS1-deficient (eds1) N. benthamiana leaves, not recognizing XopQ/HopQ1. XopQ recognition limits multiplication of Agrobacterium and attenuates levels of transiently expressed proteins. Remarkably, XopQ fails to suppress cell death reactions induced by different effectors in eds1 plants. We conclude that XopQ-mediated cell death suppression in N. benthamiana is due to the attenuation of Agrobacterium-mediated protein expression rather than the cause of the genuine XopQ virulence activity. Thus, our study expands our understanding of XopQ recognition and function, and also challenges the commonly used co-expression assays for elucidation of in planta effector activities, at least under conditions of ETI induction.
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Affiliation(s)
- Norman Adlung
- Institute for Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, 06099, Halle (Saale), Germany
| | - Ulla Bonas
- Institute for Biology, Department of Genetics, Martin Luther University Halle-Wittenberg, 06099, Halle (Saale), Germany
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14
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Monteil CL, Yahara K, Studholme DJ, Mageiros L, Méric G, Swingle B, Morris CE, Vinatzer BA, Sheppard SK. Population-genomic insights into emergence, crop adaptation and dissemination of Pseudomonas syringae pathogens. Microb Genom 2016; 2:e000089. [PMID: 28348830 PMCID: PMC5359406 DOI: 10.1099/mgen.0.000089] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/13/2016] [Indexed: 12/24/2022] Open
Abstract
Many bacterial pathogens are well characterized but, in some cases, little is known about the populations from which they emerged. This limits understanding of the molecular mechanisms underlying disease. The crop pathogen Pseudomonas syringae sensu lato has been widely isolated from the environment, including wild plants and components of the water cycle, and causes disease in several economically important crops. Here, we compared genome sequences of 45 P. syringae crop pathogen outbreak strains with 69 closely related environmental isolates. Phylogenetic reconstruction revealed that crop pathogens emerged many times independently from environmental populations. Unexpectedly, differences in gene content between environmental populations and outbreak strains were minimal with most virulence genes present in both. However, a genome-wide association study identified a small number of genes, including the type III effector genes hopQ1 and hopD1, to be associated with crop pathogens, but not with environmental populations, suggesting that this small group of genes may play an important role in crop disease emergence. Intriguingly, genome-wide analysis of homologous recombination revealed that the locus Psyr 0346, predicted to encode a protein that confers antibiotic resistance, has been frequently exchanged among lineages and thus may contribute to pathogen fitness. Finally, we found that isolates from diseased crops and from components of the water cycle, collected during the same crop disease epidemic, form a single population. This provides the strongest evidence yet that precipitation and irrigation water are an overlooked inoculum source for disease epidemics caused by P. syringae.
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Affiliation(s)
- Caroline L Monteil
- 4Laboratoire de Bioénergétique Cellulaire, Institut de Biosciences et Biotechnologies d'Aix-Marseille, CEA, 13108, Saint-Paul-lès-Durance, France.,3INRA, UR0407 Pathologie Végétale, Montfavet cedex, France.,1Institute of Life Science, College of Medicine, Swansea University, Swansea, UK.,2Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, USA
| | - Koji Yahara
- 1Institute of Life Science, College of Medicine, Swansea University, Swansea, UK.,5National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Leonardos Mageiros
- 1Institute of Life Science, College of Medicine, Swansea University, Swansea, UK
| | - Guillaume Méric
- 7The Milner Centre for Evolution, Department of Biology and Biotechnology, University of Bath, Claverton Down, Bath, UK
| | - Bryan Swingle
- 8School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
| | - Cindy E Morris
- 3INRA, UR0407 Pathologie Végétale, Montfavet cedex, France
| | - Boris A Vinatzer
- 2Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, USA
| | - Samuel K Sheppard
- 7The Milner Centre for Evolution, Department of Biology and Biotechnology, University of Bath, Claverton Down, Bath, UK.,9Department of Zoology, University of Oxford, Oxford, UK
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15
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Adlung N, Prochaska H, Thieme S, Banik A, Blüher D, John P, Nagel O, Schulze S, Gantner J, Delker C, Stuttmann J, Bonas U. Non-host Resistance Induced by the Xanthomonas Effector XopQ Is Widespread within the Genus Nicotiana and Functionally Depends on EDS1. FRONTIERS IN PLANT SCIENCE 2016; 7:1796. [PMID: 27965697 PMCID: PMC5127841 DOI: 10.3389/fpls.2016.01796] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/15/2016] [Indexed: 05/18/2023]
Abstract
Most Gram-negative plant pathogenic bacteria translocate effector proteins (T3Es) directly into plant cells via a conserved type III secretion system, which is essential for pathogenicity in susceptible plants. In resistant plants, recognition of some T3Es is mediated by corresponding resistance (R) genes or R proteins and induces effector triggered immunity (ETI) that often results in programmed cell death reactions. The identification of R genes and understanding their evolution/distribution bears great potential for the generation of resistant crop plants. We focus on T3Es from Xanthomonas campestris pv. vesicatoria (Xcv), the causal agent of bacterial spot disease on pepper and tomato plants. Here, 86 Solanaceae lines mainly of the genus Nicotiana were screened for phenotypical reactions after Agrobacterium tumefaciens-mediated transient expression of 21 different Xcv effectors to (i) identify new plant lines for T3E characterization, (ii) analyze conservation/evolution of putative R genes and (iii) identify promising plant lines as repertoire for R gene isolation. The effectors provoked different reactions on closely related plant lines indicative of a high variability and evolution rate of potential R genes. In some cases, putative R genes were conserved within a plant species but not within superordinate phylogenetical units. Interestingly, the effector XopQ was recognized by several Nicotiana spp. lines, and Xcv infection assays revealed that XopQ is a host range determinant in many Nicotiana species. Non-host resistance against Xcv and XopQ recognition in N. benthamiana required EDS1, strongly suggesting the presence of a TIR domain-containing XopQ-specific R protein in these plant lines. XopQ is a conserved effector among most xanthomonads, pointing out the XopQ-recognizing RxopQ as candidate for targeted crop improvement.
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Affiliation(s)
- Norman Adlung
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
- *Correspondence: Norman Adlung
| | - Heike Prochaska
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Sabine Thieme
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Anne Banik
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Doreen Blüher
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Peter John
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Oliver Nagel
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Sebastian Schulze
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Johannes Gantner
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Carolin Delker
- Department of Crop Physiology, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-WittenbergHalle, Germany
| | - Johannes Stuttmann
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
| | - Ulla Bonas
- Department of Genetics, Institute for Biology, Martin Luther University Halle-WittenbergHalle, Germany
- Ulla Bonas
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16
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Lin ZJD, Liebrand TWH, Yadeta KA, Coaker G. PBL13 Is a Serine/Threonine Protein Kinase That Negatively Regulates Arabidopsis Immune Responses. PLANT PHYSIOLOGY 2015; 169:2950-62. [PMID: 26432875 PMCID: PMC4677916 DOI: 10.1104/pp.15.01391] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/30/2015] [Indexed: 05/17/2023]
Abstract
Receptor-like cytoplasmic kinases (RLCKs) are a subset of plant receptor-like kinases lacking both extracellular and transmembrane domains. Some of the 46 members in the Arabidopsis (Arabidopsis thaliana) RLCK subfamily VII have been linked to plant innate immunity; however, most remain uncharacterized. Thus, multiple subfamily VII members are expected to be involved in plant immune signaling. Here, we investigate the role of AvrPphB SUSCEPTIBLE1-LIKE13 (PBL13), a subfamily VII RLCK with unique domain architecture. Unlike other characterized RLCKs, PBL13 transfer DNA insertion lines exhibit enhanced disease resistance after inoculation with virulent Pseudomonas syringae. The pbl13-2 knockout also exhibits elevated basal-level expression of the PATHOGENESIS-RELATED GENE1 defense marker gene, enhanced reactive oxygen species (ROS) burst in response to perception of bacterial microbial patterns, and accelerated flagellin-induced activation of mitogen-activated protein kinases. Recombinant PBL13 is an active kinase, and its primary autophosphorylated sites map to a 15-amino acid repeat motif unique to PBL13. Complementation of pbl13-2 with PBL13-3xFLAG converts the enhanced resistance and elevated ROS phenotypes back to wild-type levels. In contrast, kinase-dead PBL13(K111A)-3xFLAG was unable to rescue pbl13-2 disease phenotypes. Consistent with the enhanced ROS burst in the pbl13-2 knockout, PBL13 is able to associate with the nicotinamide adenine dinucleotide phosphate, reduced oxidase RESPIRATORY BURST OXIDASE HOMOLOG PROTEIN D (RBOHD) by split-luciferase complementation assay, and this association is disrupted by flagellin treatment. We conclude that the PBL13 kinase negatively regulates plant innate immunity to pathogenic bacteria and can associate with RBOHD before pathogen perception. These data are consistent with the hypothesis that PBL13 acts to prevent inappropriate activation of defense responses in the absence of pathogen challenge.
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Affiliation(s)
- Zuh-Jyh Daniel Lin
- Department of Plant Pathology, University of California, Davis, California 95616
| | - Thomas W H Liebrand
- Department of Plant Pathology, University of California, Davis, California 95616
| | - Koste A Yadeta
- Department of Plant Pathology, University of California, Davis, California 95616
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California 95616
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17
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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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18
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Targeting of plant pattern recognition receptor-triggered immunity by bacterial type-III secretion system effectors. Curr Opin Microbiol 2015; 23:14-22. [DOI: 10.1016/j.mib.2014.10.009] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 10/16/2014] [Accepted: 10/24/2014] [Indexed: 01/08/2023]
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19
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Hann DR, Domínguez-Ferreras A, Motyka V, Dobrev PI, Schornack S, Jehle A, Felix G, Chinchilla D, Rathjen JP, Boller T. The Pseudomonas type III effector HopQ1 activates cytokinin signaling and interferes with plant innate immunity. THE NEW PHYTOLOGIST 2014; 201:585-598. [PMID: 24124900 DOI: 10.1111/nph.12544] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/02/2013] [Indexed: 05/26/2023]
Abstract
We characterized the molecular function of the Pseudomonas syringae pv. tomato DC3000 (Pto) effector HopQ1. In silico studies suggest that HopQ1 might possess nucleoside hydrolase activity based on the presence of a characteristic aspartate motif. Transgenic Arabidopsis lines expressing HopQ1 or HopQ1 aspartate mutant variants were characterized with respect to flagellin triggered immunity, phenotype and changes in phytohormone content by high-performance liquid chromatography-MS (HPLC-MS). We found that HopQ1, but not its aspartate mutants, suppressed all tested immunity marker assays. Suppression of immunity was the result of a lack of the flagellin receptor FLS2, whose gene expression was abolished by HopQ1 in a promoter-dependent manner. Furthermore, HopQ1 induced cytokinin signaling in Arabidopsis and the elevation in cytokinin signaling appears to be responsible for the attenuation of FLS2 expression. We conclude that HopQ1 can activate cytokinin signaling and that moderate activation of cytokinin signaling leads to suppression of FLS2 accumulation and thus defense signaling.
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Affiliation(s)
- Dagmar R Hann
- Section of Plant Physiology, Botanical Institute, Hebelstrasse 1, CH-4056, Basel, Switzerland
| | - Ana Domínguez-Ferreras
- Section of Plant Physiology, Botanical Institute, Hebelstrasse 1, CH-4056, Basel, Switzerland
| | - Vaclav Motyka
- Institute of Experimental Botany AS CR, Rozvojová 263, 165 02, Praha 6 - Lysolaje, Czech Republic
| | - Petre I Dobrev
- Institute of Experimental Botany AS CR, Rozvojová 263, 165 02, Praha 6 - Lysolaje, Czech Republic
| | | | - Anna Jehle
- Forschungsgruppe Pflanzenbiochemie, ZMBP - Zentrum für Molekularbiologie der Pflanzen, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 5, 72076, Tübingen, Germany
| | - Georg Felix
- Forschungsgruppe Pflanzenbiochemie, ZMBP - Zentrum für Molekularbiologie der Pflanzen, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 5, 72076, Tübingen, Germany
| | - Delphine Chinchilla
- Section of Plant Physiology, Botanical Institute, Hebelstrasse 1, CH-4056, Basel, Switzerland
| | - John P Rathjen
- The Australian National University, The Linnaeus Building, Building 134, Linnaeus Way, Canberra, ACT, 0200, Australia
| | - Thomas Boller
- Section of Plant Physiology, Botanical Institute, Hebelstrasse 1, CH-4056, Basel, Switzerland
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20
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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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