Genome-wide identification of BcR2R3-MYB transcription factors as candidate regulators of flavonoid biosynthesis in Chinese cabbage

Flavonoids are crucial plant secondary metabolites that play vital roles in development and stress responses. While R2R3-MYB transcription factors are known regulators of flavonoid biosynthesis, their specific role in Chinese cabbage ( Brassica campestris syn. B. rapa ), especially under abiotic stress conditions like heat and drought, remains poorly understood. This study systematically identified R2R3-MYB transcription factors in Chinese cabbage (BcR2R3-MYB) and pinpointed members potentially involved in both flavonoid biosynthesis and abiotic stress responses. We identified 215 BcR2R3-MYBs, with structural analyses revealing conserved MYB domains. Furthermore, diverse cis-acting elements were observed, including those related to growth, phytohormones, and stress. Integrative analysis of cis-elements, phylogenetic relationships, and expression patterns revealed specific BcR2R3-MYB members with dual regulatory potential in these pathways. In particular, BcMYB12-LF/MF2 were identified as putative positive regulators of these processes, exhibiting strong floral expression and potential roles in pigmentation and thermotolerance. These findings provide a foundation for exploring BcR2R3-MYB s as candidate molecular breeding targets to potentially improve flavonoid accumulation and abiotic stress tolerance in Chinese cabbage.