Overexpression of DRM2 Increases Resistance to Botrytis cinerea by Modulating JA Signalling Pathway in Tomato.

The fungal pathogen Botrytis cinerea (B. cinerea) is highly destructive and threatens tomato production and shelf life. While plant defence mechanisms against B. cinerea are well-studied, its epigenetic regulation remains largely unknown. DRM2-mediated de novo DNA methylation plays pivotal roles in plant development and stress adaptation, yet its contribution to tomato resistance against fungal pathogens remains largely unclear. In this study, we show that tomato with lower global DNA methylation levels exhibit stronger resistance to B. cinerea, revealing a key contribution of epigenetic regulation to plant immunity. To determine the role of DRM2 in tomato defence against B. cinerea, we conducted an integrative multi-omics analysis. Further investigation revealed that overexpression of DRM2 promoted jasmonic acid (JA) accumulation and activated the JA-mediated signalling pathway, thereby enhancing tomato resistance to B. cinerea. Particularly, DRM2 was shown to bind the promoter of AOS, a key gene in JA biosynthesis, modulating its epigenetic state. Overall, this study uncovers the epigenetic mechanisms governing plant defence against B. cinerea and identifies a promising candidate gene for breeding tomatoes with enhanced disease resistance.