TCP15 negatively regulates anthocyanin biosynthesis under low light in Brassica

Low light caused by industrial development and environment change has become a limitation in crop production. This condition inhibits the stalk anthocyanin synthesis and even its tastes in brassica rapa L; however, the molecular basis on the inhibitory effects by low light on anthocyanin synthesis in brassica stalk is less reported. In this study, we combined transcriptomes and metabolisms to decipher key genes and /or metabolites that responsible for shading acclimation in a brassica cultivar, XH1. Results shows that anthocyanin is obviously repressed in low light condition, and consistently the structural genes related to anthocyanin biosynthesis pathway is significantly enriched in the list of differentially expressed genes according to both GO and KEGG analysis. Furthermore, amounts of some metabolites related to anthocyanin are dramatically decreased under shading treatment, such as cyanindin 3-O-glucoside chloride, cyanindin O-syringic acid, and cyanidin 3-O-rutinoside. In addition, we found that some transcription factors of interest such as TCP15 is stimulated by shading treatments, while acts as a negative regulator anthocyanin biosynthesis by low light. The mechanistic explanation of inhibitory effects of anthocyanin by low light condition through TCP15 was proposed. This study extend our knowledge on transcriptional regulation mechanism for anthocyanin biosynthesis in response to shading condition, and provides an evidence that a potential role of TCP15 in low light inhibitory effects in anthocyanin synthesis in brassica.