The surprising role of VvLYK6 in grapevine immune responses triggered by chitin oligomers
For sustainable viticulture, the substitution of chemical inputs with biocontrol products has become one of the most considered strategies. This strategy is based on elicitor-triggered immunity that requires a deep understanding of the molecular mechanisms involved in plant defense activation. Plant immune responses are triggered through the perception of conserved microbe-associated molecular patterns (MAMPs) which are recognized by pattern recognition receptors (PRRs) at the plasma membrane. Chitin, the major component of fungal cell walls, is well known to elicit plant immune responses. In Vitis vinifera, knowledge about the perception and immune responses triggered by chitin oligomers is now better understood . Among the LysM receptor-like kinases (LysM-RLKs) family of PRRs, which includes 16 members in Vitis vinifera, three of them (VvLYK1-1, VvLYK1-2 and VvLYK5-1) are involved in the perception of chitin oligomers to trigger plant immune responses [1,2]. Recently, another member of this family, named VvLYK6, was identified in grapevine as being overexpressed following a Botrytis cinerea infection. We characterized the role of VvLYK6 in plant immunity by overexpressing it in Arabidopsis thaliana and grapevine. Surprisingly, overexpression of VvLYK6 decreased chitin-induced MAPK activation, defense gene expression, callose deposition and increased plant sensitivity to fungal infections. According to these results, VvLYK6 negatively regulates chitin-induced defense reactions in grapevine and could be considered as a susceptibility gene in the context of fungal infections.
Acknowledgements: We acknowledge Institut Carnot Plant2Pro for funding the VitiLYKs project and DimaCell platform (Dijon, France) for the confocal microscopy.
1) Roudaire T. et al. (2023) The grapevine LysM receptor-like kinase VvLYK5-1 recognizes chitin oligomers through its association with VvLYL1-1. Front. Plant Sci. 14:1130782 DOI 10.3389/fpls.2023.1130782
2) Brulé D. et al. (2019) The grapevine (Vitis vinifera) LysM receptor kinases VvLYK1-1 and VvLYK1-2 mediate chitooligosaccharide-triggered immunity. Plant Biotechnol. J. 17, 812–825. DOI 10.1111/pbi.13017
Issue: ICGWS 2023
1Agroécologie, CNRS, INRAE, Institut Agro, Univ. Bourgogne, Univ. Bourgogne Franche-Comté, Dijon, France.