CpMYB12 and CpMYB4 orchestrate antagonistic regulation of anthocyanin biosynthesis underlying bud sport-mediated floral color variation in Chimonanthus praecox

Chimonanthus praecox (L.) Link (wintersweet), a rare winter-blooming woody plant, typically produces yellow flowers. However, under high light intensity, the cultivar ‘TZ017’ exhibits a red-flowered mutant characterized by elevated anthocyanin accumulation, particularly cyanidin-3-O-rutinoside and delphinidin-3-O-rutinoside. Integrated metabolomic and transcriptomic analyses revealed that transcription factors CpMYB12 and CpMYB4 play key regulatory roles in this pigmentation shift. CpMYB12 directly activates early flavonoid biosynthetic genes ( CpCHS1 , CpF3H ) and, when co-expressed with CpbHLH128 and CpTTG1, also promotes CpLDOX expression, leading to enhanced anthocyanin biosynthesis. CpMYB12 expression is upregulated in RS and linked to the photoreceptor CpUVR8 , suggesting light-responsive regulation. Conversely, CpMYB4 functions as a transcriptional repressor of anthocyanin biosynthesis. The antagonistic relationship between CpMYB12 and CpMYB4 maintains flavonoid homeostasis in ‘TZ017’. This study identifies CpMYB12 and CpMYB4 as core regulators of flavonoid metabolism and floral pigmentation in C. praecox, proposing them as potential targets for improving ornamental traits and developing wintersweet as a novel source of natural pigments and high-value phytochemicals. These findings lay a theoretical foundation for both adaptive trait enhancement and industrial application of this species. ● Floral color mutation in C. praecox ‘TZ017’ is linked to differential anthocyanin accumulation. ● Integrated transcriptomic and metabolomic analyses identify CpMYB12 and CpMYB4 as key regulators. ● CpMYB12 forms an MBW complex with CpbHLH128 and CpTTG1 to activate anthocyanin biosynthetic genes. ● CpMYB4 acts as a repressor inhibiting the expression of core flavonoid biosynthesis genes. ● Findings offer molecular targets for flower color improvement and pigment-based industrial utilization.