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Kharel A, Islam MT, Rookes J, Cahill D. How to Unravel the Key Functions of Cryptic Oomycete Elicitin Proteins and Their Role in Plant Disease. PLANTS 2021; 10:plants10061201. [PMID: 34204633 PMCID: PMC8231210 DOI: 10.3390/plants10061201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 12/13/2022]
Abstract
Pathogens and plants are in a constant battle with one another, the result of which is either the restriction of pathogen growth via constitutive or induced plant defense responses or the pathogen colonization of plant cells and tissues that cause disease. Elicitins are a group of highly conserved proteins produced by certain oomycete species, and their sterol binding ability is recognized as an important feature in sterol–auxotrophic oomycetes. Elicitins also orchestrate other aspects of the interactions of oomycetes with their plant hosts. The function of elicitins as avirulence or virulence factors is controversial and is dependent on the host species, and despite several decades of research, the function of these proteins remains elusive. We summarize here our current understanding of elicitins as either defense-promoting or defense-suppressing agents and propose that more recent approaches such as the use of ‘omics’ and gene editing can be used to unravel the role of elicitins in host–pathogen interactions. A better understanding of the role of elicitins is required and deciphering their role in host–pathogen interactions will expand the strategies that can be adopted to improve disease resistance and reduce crop losses.
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Solanský M, Mikulášek K, Zapletalová M, Petřivalský M, Chiltz A, Zdráhal Z, Leborgne-Castel N, Lochman J. The oligomeric states of elicitins affect the hypersensitive response and resistance in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3219-3234. [PMID: 33475728 DOI: 10.1093/jxb/erab011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Abstract
Successful plant defence against microbial pathogens is based on early recognition and fast activation of inducible responses. Key mechanisms include detection of microbe-associated molecular patterns by membrane-localized pattern recognition receptors that induce a basal resistance response. A well-described model of such responses to pathogens involves the interactions between Solanaceae plants and proteinaceous elicitors secreted by oomycetes, called elicitins. It has been hypothesized that the formation of oligomeric structures by elicitins could be involved in their recognition and activation of defensive transduction cascades. In this study, we tested this hypothesis using several approaches, and we observed differences in tobacco plant responses induced by the elicitin β-cryptogein (β-CRY) and its homodimer, β-CRYDIM. We also found that the C-terminal domain of elicitins of other ELI (true-elicitin) clades plays a significant role in stabilization of their oligomeric structure and restraint in the cell wall. In addition, covalently cross-linking β-CRYDIM impaired the formation of signalling complexes, thereby reducing its capacity to elicit the hypersensitive response and resistance in the host plant, with no significant changes in pathogenesis-related protein expression. By revealing the details of the effects of β-CRY dimerization on recognition and defence responses in tobacco, our results shed light on the poorly understood role of elicitins' oligomeric structures in the interactions between oomycetes and plants.
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Affiliation(s)
- Martin Solanský
- Department of Biochemistry, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Kamil Mikulášek
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Martina Zapletalová
- Department of Biochemistry, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | - Marek Petřivalský
- Department of Biochemistry, Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Annick Chiltz
- Agroécologie, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Zbyněk Zdráhal
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Nathalie Leborgne-Castel
- Agroécologie, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Jan Lochman
- Department of Biochemistry, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
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