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Kotsaridis K, Michalopoulou VA, Tsakiri D, Kotsifaki D, Kefala A, Kountourakis N, Celie PHN, Kokkinidis M, Sarris PF. The functional and structural characterization of Xanthomonas campestris pv. campestris core effector XopP revealed a new kinase activity. Plant J 2023; 116:100-111. [PMID: 37344990 DOI: 10.1111/tpj.16362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 06/23/2023]
Abstract
Exo70B1 is a protein subunit of the exocyst complex with a crucial role in a variety of cell mechanisms, including immune responses against pathogens. The calcium-dependent kinase 5 (CPK5) of Arabidopsis thaliana (hereafter Arabidopsis), phosphorylates AtExo70B1 upon functional disruption. We previously reported that, the Xanthomonas campestris pv. campestris effector XopP compromises AtExo70B1, while bypassing the host's hypersensitive response, in a way that is still unclear. Herein we designed an experimental approach, which includes biophysical, biochemical, and molecular assays and is based on structural and functional predictions, utilizing AplhaFold and DALI online servers, respectively, in order to characterize the in vivo XccXopP function. The interaction between AtExo70B1 and XccXopP was found very stable in high temperatures, while AtExo70B1 appeared to be phosphorylated at XccXopP-expressing transgenic Arabidopsis. XccXopP revealed similarities with known mammalian kinases and phosphorylated AtExo70B1 at Ser107, Ser111, Ser248, Thr309, and Thr364. Moreover, XccXopP protected AtExo70B1 from AtCPK5 phosphorylation. Together these findings show that XccXopP is an effector, which not only functions as a novel serine/threonine kinase upon its host target AtExo70B1 but also protects the latter from the innate AtCPK5 phosphorylation, in order to bypass the host's immune responses. Data are available via ProteomeXchange with the identifier PXD041405.
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Affiliation(s)
- Konstantinos Kotsaridis
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Vassiliki A Michalopoulou
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Dimitra Tsakiri
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
| | - Dina Kotsifaki
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
| | - Aikaterini Kefala
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Nikos Kountourakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Patrick H N Celie
- Division of Biochemistry, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Michael Kokkinidis
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Panagiotis F Sarris
- Department of Biology, University of Crete, Heraklion, 714 09, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
- Biosciences, University of Exeter, Exeter, UK
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Michalopoulou VA, Mermigka G, Kotsaridis K, Mentzelopoulou A, Celie PHN, Moschou PN, Jones JDG, Sarris PF. The host exocyst complex is targeted by a conserved bacterial type-III effector that promotes virulence. Plant Cell 2022; 34:3400-3424. [PMID: 35640532 PMCID: PMC9421483 DOI: 10.1093/plcell/koac162] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 05/23/2022] [Indexed: 05/30/2023]
Abstract
For most Gram-negative bacteria, pathogenicity largely depends on the type-III secretion system that delivers virulence effectors into eukaryotic host cells. The subcellular targets for the majority of these effectors remain unknown. Xanthomonas campestris, the causal agent of black rot disease of crucifers such as Brassica spp., radish, and turnip, delivers XopP, a highly conserved core-effector protein produced by X. campestris, which is essential for virulence. Here, we show that XopP inhibits the function of the host-plant exocyst complex by direct targeting of Exo70B, a subunit of the exocyst complex, which plays a significant role in plant immunity. XopP interferes with exocyst-dependent exocytosis and can do this without activating a plant NOD-like receptor that guards Exo70B in Arabidopsis. In this way, Xanthomonas efficiently inhibits the host's pathogen-associated molecular pattern (PAMP)-triggered immunity by blocking exocytosis of pathogenesis-related protein-1A, callose deposition, and localization of the FLAGELLIN SENSITIVE2 (FLS2) immune receptor to the plasma membrane, thus promoting successful infection. Inhibition of exocyst function without activating the related defenses represents an effective virulence strategy, indicating the ability of pathogens to adapt to host defenses by avoiding host immunity responses.
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Affiliation(s)
- Vassiliki A Michalopoulou
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | - Glykeria Mermigka
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | - Konstantinos Kotsaridis
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
| | | | - Patrick H N Celie
- Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Panagiotis N Moschou
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnean Center for Plant Biology, Uppsala S-75007, Sweden
| | | | - Panagiotis F Sarris
- Department of Biology, University of Crete, Heraklion, Crete 714 09, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete 70013, Greece
- Biosciences, University of Exeter, Exeter, UK
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Kotsaridis K, Tsakiri D, Sarris PF. Understanding enemy's weapons to an effective prevention: common virulence effects across microbial phytopathogens kingdoms. Crit Rev Microbiol 2022:1-15. [PMID: 35709325 DOI: 10.1080/1040841x.2022.2083939] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Plant-pathogens interaction is an ongoing confrontation leading to the emergence of new diseases. The majority of the invading microorganisms inject effector proteins into the host cell, to bypass the sophisticated defense system of the host. However, the effectors could also have other specialized functions, which can disrupt various biological pathways of the host cell. Pathogens can enrich their effectors arsenal to increase infection success or expand their host range. This usually is accomplished by the horizontal gene transfer. Nowadays, the development of specialized software that can predict proteins structure, has changed the experimental designing in effectors' function research. Different effectors of distinct plant pathogens tend to fold alike and have the same function and focussed structural studies on microbial effectors can help to uncover their catalytic/functional activities, while the structural similarity can enable cataloguing the great number of pathogens' effectors. In this review, we collectively present phytopathogens' effectors with known enzymatic functions and proteins structure, originated from all the kingdoms of microbial plant pathogens. Presentation of their common domains and motifs is also included. We believe that the in-depth understanding of the enemy's weapons will help the development of new strategies to prevent newly emerging or re-emerging plant pathogens.
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Affiliation(s)
| | | | - Panagiotis F Sarris
- Department of Biology, University of Crete, Crete, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Crete, Greece.,Biosciences, University of Exeter, Exeter, UK
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Sertedakis M, Kotsaridis K, Tsakiri D, Mermigka G, Dominguez‐Ferreras A, Ntoukakis V, Sarris P. Expression of putative effectors of different Xylella fastidiosa strains triggers cell death-like responses in various Nicotiana model plants. Mol Plant Pathol 2022; 23:148-156. [PMID: 34628713 PMCID: PMC8659589 DOI: 10.1111/mpp.13147] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 06/12/2023]
Abstract
The wide host range of Xylella fastidiosa (Xf) indicates the existence of yet uncharacterized virulence mechanisms that help pathogens to overcome host defences. Various bioinformatics tools combined with prediction of the functions of putative virulence proteins are valuable approaches to study microbial pathogenicity. We collected a number of putative effectors from three Xf strains belonging to different subspecies: Temecula-1 (subsp. fastidiosa), CoDiRO (subsp. pauca), and Ann-1 (subsp. sandyi). We designed an in planta Agrobacterium-based expression system that drives the expressed proteins to the cell apoplast, in order to investigate their ability to activate defence in Nicotiana model plants. Multiple Xf proteins differentially elicited cell death-like phenotypes in different Nicotiana species. These proteins are members of different enzymatic groups: (a) hydrolases/hydrolase inhibitors, (b) serine proteases, and (c) metal transferases. We also classified the Xf proteins according to their sequential and structural similarities via the I-TASSER online tool. Interestingly, we identified similar proteins that were able to differentially elicit cell death in different cultivars of the same species. Our findings provide a basis for further studies on the mechanisms that underlie both defence activation in Xf resistant hosts and pathogen adaptation in susceptible hosts.
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Affiliation(s)
| | - Konstantinos Kotsaridis
- Department of BiologyUniversity of CreteHeraklionGreece
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
| | - Dimitra Tsakiri
- Department of BiologyUniversity of CreteHeraklionGreece
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
| | - Glykeria Mermigka
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
| | | | | | - Panagiotis F. Sarris
- Department of BiologyUniversity of CreteHeraklionGreece
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
- BiosciencesUniversity of ExeterExeterUK
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Beris D, Kotsaridis K, Vakirlis N, Termentzi A, Theologidis I, Moury B, Vassilakos N. The plasma membrane Cation binding protein 1 affects accumulation of Potato virus Y in pepper both at the systemic level and in protoplasts. Virus Res 2020; 280:197899. [PMID: 32067976 DOI: 10.1016/j.virusres.2020.197899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 11/18/2022]
Abstract
The Plasma membrane Cation binding Protein 1 (PCaP1) has been shown to be important for the intra-cellular movement of two members of the Potyvirus genus in arabidopsis and tobacco plants. In this study, the orthologous PCaP1 gene of pepper (Capsicum annuum) was examined for its role in the accumulation of Potato virus Y, type member of the Potyvirus. Downregulation of C. annuum PCaP (CaPCaP) through tobacco rattle virus-induced gene silencing, resulted in lower accumulation of potato virus Y (PVY) in pepper plants. Using an improved pepper protoplast isolation protocol, we showed that knockdown of CaPCaP negatively affected PVY accumulation at the within-cell level in pepper in contrast with the turnip mosaic virus-arabidopsis pathosystem. Conversely, following overexpression of CaPCaP, the accumulation of PVY at the systemic level was increased. The results provide further knowledge on the role of PCaP in the potyvirus infection process and reveal differences of its action among different pathosystems.
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Affiliation(s)
- Despoina Beris
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Virology, 14561 Kifissia, Greece.
| | - Konstantinos Kotsaridis
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Virology, 14561 Kifissia, Greece.
| | - Nikolaos Vakirlis
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Virology, 14561 Kifissia, Greece.
| | - Aikaterini Termentzi
- Benaki Phytopathological Institute, Department of Pesticides Control and Phytopharmacy, 14561 Kifissia, Greece.
| | - Ioannis Theologidis
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Virology, 14561 Kifissia, Greece.
| | - Benoit Moury
- Pathologie Végétale, INRA, 84140 Montfavet, France.
| | - Nikon Vassilakos
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Virology, 14561 Kifissia, Greece.
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