Cloning of F3 ' 5 ' Hand the correlation between this gene and delphinidin biosynthesis in Salvia splendens

Flavonoid 3'5' hydroxylase (F3'5'H) is a key enzyme catalyzing the formation of dihydromyricetin, which is converted into delphindin in the anthocyanins biosynthesis. This process determines whether or not flowers can appear blue to a certain extent. Four scarlet sage cultivars (`Vista Lavender, Aoyunshenghuo, 'Vista Rose' and 'Vista white') were used in this study. First, we detected the composition of anthocyanins in flowers of these four cultivars using ultra performance liquid chromatography-mass spectrometry (UPLC-MS). The lavender flowers contained three classes of anthocyanin compounds for color pigmentation: delphinidin, cyanidin and pelargonidin. The red flower pigment from Aoyunshenghuo' contained two pelargonidin-based anthocyanins. The 'Vista Rose' flowers contained cyanidin-and pelargonidin-based anthocyanins. In contrast, no color anthocyanins or derivatives were detected in the white flowers. It is expected that, in contrast to the blue flowers, the biosynthesis of delphinidin in the red and the white flowers could be cut off. It is inferred that this phenomenon could be related to F3'5'H. Second, we isolated F3'5'Hs separately from these four cultivars. It was unexpected that F3'5'H displayed a complete same sequence in these four different cultivars showing significant differences on the biosynthesis of blue anthocyanin Dp. We speculate that the expression of F3'5'H could be related to the synthesis of Dp. To verify the hypothesis, the expression of F3'5'H in stems and flowers was conducted by reverse transcription polymerase chain reaction (RT-PCR). Compared with the red and the white cultivars, F3'5'H showed high expression levels in both the stems and flowers of the lavender cultivar. For the red cultivars 'Aoyunshenghuo' and 'Vista rose; the expression levels of F3'5'H in the blue stem nodes were significant higher than the ones in the flowers. This result showed there was a positive correlation between the biosynthesis of Dp and the expression of F3'5'H. Taken together, this study might provide a theoretical support for flower color-associated breeding in Salvia splendens.