Correlations Among the Enzyme Activity and Gene Expression of Dihydroflavonol 4-Reductase and Anthocyanin Accumulation in Purple-Fleshed Sweet Potato

【Objective】Two purple-fleshed sweet potato cultivar and strain,‘A5’ and ‘Yamakawamurasaki’,and one white-fleshed sweet potato cultivar ‘Yubeibai’ were used to study the role of dihydroflavonol 4-reductase(DFR) in anthocyanin accumulation of purple-fleshed sweet potato.【Method】Anthocyanin content,DFR activities and expression of IbDFR gene were determined respectively,while the correlation between the content of anthocyanin and DFR activities,and that between anthocyanin content and IbDFR gene expression were analyzed.【Result】The results showed that the activities of DFR were dramatically and positively correlated with the content of anthocyanin no matter in different organs of the same cultivar(strain) or in same organ of the same cultivar(strain) at different growth stages.Moreover,the variation trends of the relative expression of IbDFR gene also coincided with that of anthocyanin content in storage roots of different cultivars(strain) and of different developing states of ‘Yamakawamurasaki’.【Conclusion】These results indicate that DFR is a key enzyme in anthocyanin synthesis of purple-fleshed sweet potato,and the biosynthesis of anthocyanin is in situ synthesis in purple-fleshed sweet potato.