Comprehensive transcriptomics and metabolomics reveal the coloring mechanism of purple Camellia tachangensis.

Species within the Camellia sect. Theaceae of the genus Camellia, mianly distributed in Southwestern China, including Guizhou, Yunnan, and Sichuan, processes abundant wild germplasm for providing possible commercial cultivars breeding. Anthocyanins are an important functional component in tea and have been widespread attention. Two tea plants with different leaf colors: 'P113'from Camellia tachangensis F. C. Zhang and the buds and leaves are light red, 'C8' from C. sinensis (L.) Kuntze and the buds are green and the leaves purple. However, the molecular mechanism of the purple difference in bud between the C. tachangensis 'P113' and C.sinensis 'C8' has not been revealed. In this study, the anthocyanin components and the corresponding molecular mechanisms in the purple buds of C. tachangensis 'P113' and C. sinensis 'C8' were performed comparative analysis by using the transcriptome and metabolome analysis. The results showed that the relative contents of anthocyanin related metabolites were significantly different in bud between 'P113' and 'C8'. The relative content of pelargonidin, delphinidin and total proanthocyanidins in 'C8' buds was significantly higher than that in 'P113'. The expression level of the homologous genes in CHS, F3'5'H, ANS, LAR and ANR were significant difference between 'P113' and 'C8' in the anthocyanin synthesis pathway, and the expression level of homologous genes in 'C8' was higher than that in 'P113'. These differential genes have different regulatory effects on their related metabolites. The results can help us to understand the physiological metabolism of the purple difference in bud between C.tachangensis and C.sinensis, and help us to choose excellent purple tea plant strains from the different Species within the Sect. Thea.