Light-induced m6A RNA modification regulates anthocyanin accumulation during rose petal coloration

Light plays a crucial role in regulating anthocyanin biosynthesis during flower coloration. However, the involvement of epigenetic modifications in light-induced flower coloration remains poorly understood. Here, we studied the rose cultivar Rosa hybrida cv. Spectra, which exhibits dramatic light-induced changes in petal coloration. Integrated analysis of the m6A methylome and the transcriptome revealed significant changes in both m6A modifications and the expression of the anthocyanidin synthase gene RhANS (C_AA159414.1) in response to direct light in the petals. Light induced m6A modifications in the coding sequence (CDS) region of RhANS and repressed m6A modification at the 3' untranslated region (3'UTR). m6A modification in the CDS region enhanced mRNA stability and the translation efficiency of RhANS, whereas modification in the 3'UTR exerted an opposing effect. The expression of the m6A demethylase genes RhALKBH10A (C_AA159415.1) and RhALKBH10B (C_AA159416.1) was repressed in petals under direct light conditions. Silencing RhALKBH10A/10B enhanced anthocyanin accumulation, increased m6A abundance at CDS sites and concurrently reduced m6A abundance at the 3'UTR site of RhANS mRNA. Silencing RhANS abrogated the anthocyanin accumulation induced by RhALKBH10A/10B silencing. Our results reveal that light modulates m6A modifications to regulate mRNA stability and translation of RhANS, thereby driving petal coloration in rose.