Blue light regulates jasmonic acid synthesis via CRY1a and boosts antioxidant enzymes activity in Solanum lycopersicum to resist Botrytis cinerea.

Key message: Blue light treatment can stimulate antioxidant enzyme activity and induce JA synthesis through CRY1a enhancing the resistance of Solanum lycopersicum to Botrytis cinerea. Light signals are prevalent in the environment and significantly influence the growth, development, plant resistance, and pathogenicity of phytopathogenic fungi. The agricultural application of spectral engineering through optimized red and blue light proportions has been used as a practical methodology for synergistically improving plant photobiology, nutritional metabolism, and environmental adaptation capabilities. However, its role in plant disease resistance has not been comprehensively explored. In our study, the pathogenicity analysis indicates that blue light significantly enhances the resistance of Solanum lycopersicum to Botrytis cinerea. Transcriptomic profiling revealed that blue light activates OPR3 and JAR1 expression, concomitant with elevated jasmonic acid biosynthesis and significantly enhanced activities of key antioxidant enzymes including peroxidase, catalase, and ascorbate peroxidase in S. lycopersicum. Furthermore, the mutation of the blue light receptor cryptochrome 1a (CRY1a) was found to enhance S. lycopersicum resistance to B. cinerea. For the pathogen B. cinerea, blue light was observed to induce DHN-melanin synthesis-related genes Bop2, Bcbrn2, Bcpks4, and Bcpks21 expression, and the development of its infection cushion was notably slower under blue light in B. cinerea. The above results indicate that blue light can control tomato gray mold by enhancing S. lycopersicum resistance and suppressing B. cinerea infection, which suggests that blue light may possess potential application value in disease management for facility-based S. lycopersicum cultivation. Our study reveals how blue light and light receptor CRY1a function in S. lycopersicum to defend necrotrophic fungal pathogens.