Integrated metabolomic and transcriptomic analyses reveal differences in the biosynthetic pathway of anthocyanins in Fragaria nilgerrensis and Fragaria pentaphylla

摘要

Anthocyanins, which commonly exist in fruits, have substantial benefits for human health. Fragaria nilgerrensis and F. pentaphylla are two species of wild strawberry with white and red fruits, respectively. To understand the molecular mechanism that underlies the biosynthesis of anthocyanins in strawberry, combined analyses of transcriptomics and metabolomics were conducted between the two species of Fragaria to compare the anthocyanin component and the biosynthetic pathway. A total of 26 anthocyanins were obtained in both of the species. Cyanidin 3-O-glucoside chloride, cyanidin 3-galactoside, and cyanidin 3-glucoside were the major anthocyanins in F. nilgerrensis and F. pentaphylla. The content of most of the anthocyanin components in F. pentaphylla was higher than those in F. nilgerrensis. No glycoside pelargonidin was detected in the white fruits of F. nilgerrensis, revealing that the anthocyanins underlie the white mutation. Transcriptomic analysis revealed that the expression of almost all the anthocyanin structural genes and transcription factors genes MYB10 and MYB1 in the fruits of F. pentaphylla was up-regulated compared with those in the fruits of F. nilgerrensis. The results indicate that three structural genes, including chalcone synthase, dihydroflavonol reductase, and UDP-glucose: flavonol 3-O-glucosyltransferaseare likely to be the candidate genes related to anthocyanin biosynthesis in the two species of Fragaria. In addition, the lack of pelargonidin might be due to the block of transformation catalyzed by leucoanthocyanidin dioxygenase or UDP-glucose flavonoid glucosyl transferase.