Comparative transcriptome analysis of genes involved in anthocyanin synthesis in blueberry

Blueberry (Vaccinium, family Ericaceae) is well known for its strong antioxidant properties and abundant active ingredients including anthocyanins, flavonols, and proanthocyanidins. In this study, variations in anthocyanin and phenolic compounds content in Bluecrop and Northblue blueberry cultivar fruits were studied, and comparative transcriptome analysis was performed to analyze differences in the molecular mechanisms of anthocyanin biosynthesis. A total of 13 799 unique genes were identified by differential expression analysis, and further subjected to GO classification and pathway enrichment. Nine differentially expressed genes (DEGs), including CHI, DFR, F3'H, FLS, CHS, OMT, UGT, ANS and F3H, were selected to validate the differential expression data using quantitative real-time PCR. The obtained qRT-PCR expression results were consistent with the RNA-Seq results. The expression levels of 9 candidate genes involved in flavonoid biosynthesis and metabolism were concurrent with the anthocyanin content. The developmental stage appeared to affect the expression of genes related to flavonoid biosynthesis to a greater extent than the tissue or cultivar type. This study provides an abundant data resource that will further our understanding of the molecular mechanisms of anthocyanin biosynthesis in blueberries.