Abstract：Dihydroflavonol 4-reductase (DFR) is a key enzyme converting dihydroflavonols to leucoanthocyanidins in the biosynthesis of anthocyanins. EST sequencing was carried out using a cDNA library of peanut(Arachis hypogaea L.) immature seed and full length cDNA of peanut DFR was cloned. Sequence alignment showed that DFR was highly conserved among different plant species. Peanut cDNA microarray and semi-quantitative RT-PCR were used to analysis the expression of DFR in different tissues. Results indicated that the expression level was highest in gynophores and followed by flowers, while the expression in roots and leavies was low. DFR gene expression was also analysed in seeds from different cultivars, which suggested that it expressed higher in cultivars with dark-color seed coat, the expression was the highest in ZH9 seeds with black seed coat. We also analysed the expression level of DFR in a peanut mutation with purple leaves and stems, which demonstrated that DFR was highly expressed in the purple tissues. These results demonstrate that the expression level of DFR gene is positively correlation to the accumulation of anthocyanins, which indicates that DFR catalytic reaction is the key step in the biosynthesis of anthocyanins.
