Anthocyanins accumulate in tartary buckwheat (Fagopyrum tataricum) sprout in response to cold stress

Tartary buckwheat (Fagopyrum tataricum) is rich in flavonoids. Anthocyanins, a special class of flavonoids, offer significant nutrients and provide the red pigment found in sprouts. The anthocyanins biosynthesis has been shown influenced by environmental stress. In this study, we investigate the effects of cold stress on anthocyanins biosynthesis of tartary buckwheat sprouts. On cellular level, cross-sectional observations were performed and result indicated that anthocyanins accumulated primarily in the epidermal and cortex cells of hypocotyls. Biochemical analysis, including anthocyanin quantification, thin-layer chromatography and radical scavenging assay, showed that cold stress significantly increased the synthesis of anthocyanins and antioxidant activity of tartary buckwheat sprouts. At the molecular level, semi-RTPCR was used to investigate 14 anthocyanin-related genes in tartary buckwheat sprouts treated with cold stress. All the selected genes were upregulated in cold-stressed sprouts, except for FtGST, FtAHA, and FtMYB. More importantly, the expression level of three late biosynthesis genes, FtF3'H, FtDFR, and FtANS, was highest in hypocotyl tissue. Our results suggest that anthocyanins play a considerable role in the cold stress tolerance of tartary buckwheat sprouts.