Loropetalum chinense , a widely cultivated ornamental shrub, exhibits dynamic changes in leaf colour that are regulated by environmental factors, particularly light quality. However, the molecular mechanisms underlying blue light (BL)–induced anthocyanin biosynthesis remain largely unexplored. This study systematically investigated the regulatory pathways through which BL increases anthocyanin accumulation and thus influences the ornamental quality of L. chinense . Integrated transcriptomic and metabolomic approaches revealed that anthocyanin and flavonoid biosynthesis were significantly upregulated by BL, which intensified red leaf pigmentation. Metabolomic data revealed increases in specific anthocyanin metabolites, predominantly glycosides and acylated derivatives of petunidin, delphinidin, and peonidin. Transcriptomic analysis demonstrated that the BL–induced activation of circadian rhythm pathways coordinated anthocyanin biosynthesis. WGCNA identified LcHY5.1 (a core photomorphogenesis regulator) as the hub gene in the most strongly correlated module, with transgenic validation confirming its positive regulation of anthocyanin production. Additionally, this study, based on the Agrobacterium –mediated genetic transformation system previously established by our research group, provides technical support for the efficient verification of functional genes in L. chinense . The research reveals the molecular mechanism by which BL regulates anthocyanin biosynthesis in L. chinense , offering theoretical foundations and technical support for studies on light quality response mechanisms in colored–leaf plants and molecular breeding of new high–ornamental cultivars.
Zhang et al. (Sun,) studied this question.