Cloning of Cinnamate 4-hydroxylase Gene(C4H) from Tartary Buckwheat(Fagopyrum tararicum) and Its Tissue-specific Expression under UV-B Stress during Seed Germination
Abstract：Cinnamate 4-hydroxylase (C4H) is the second enzyme of phenylpropanoid metabolic pathway in plant, and its expression level affects the contents of many secondary metabolites such as flavonoid and lignin. In order to learn more about the molecular mechanisms of flavonoids biosynthesis, a cDNA encoding C4H was cloned through the methods of RT-PCR and RACE from tartary buckwheat(Fagopyrum tararicum). The results showed that the FtC4H cDNA with 1 515 bp in full-length encoded 504 amino acids including all the active sites of C4H. The semi-quantitative RT-PCR analysis showed that the expression level of FtC4H was improved in both cotyledon and hypocotyl (P<0.05) under UV-B stress. Statistical analysis indicated that both of the expression levels of FtC4H in the cotyledon and hypocotyl were significantly associated with the flavonoid contents in the relative tissues, and their correlation coefficients were 0.945 and 0.768, respectively. Our results can provide useful information to understand the relationship between expression level of FtC4H and flavoniod content induced by environmental factors in tartary buckwheat. Further more, this study indicated that FtC4H can be a new candidate target gene for developing high flavoniod tartary buckwheat by secondary metabolic engineering.
