Cloning and Bioinformatical Analysis of Dihydroflavonol 4-reductase Gene from Pigmented Potato

Abstract

The main pigment which affects flower colors is the anthocyanin, and dihydroflavonol 4-reductase (DFR) is a key enzyme in anthocyanin synthesis. In this study, we employed the native pigmented potato varieties ‘Jianchuanhong’ and ‘Zhuanxinwu’ from Yunnan Province, and the introduced potato variety ‘Heimeiren’ as the experimental materials. The complete cDNAs sequence of DFR was cloned from their tubers epidermis by RT-PCR, and the bioinformatics analysis was carried out. The sequence analysis displayed that DFR gene of the three tested pigmented potato varieties encoded 381 amino acid and had a complete open reading frame (ORF). It also showed that DFR had a highly conserved NADP(H)-binding site and substrate specificity site. Homologous alignment result demonstrated that the nucleotide similarity and amino acid homology of the three kinds of pigmente potato species are 99.24%, 98.78%, respectively. And the amino acid homology of these pigmented potatoes with other Solanaceae plants, such as Nicotiana alata and Petunia x hybrida , were more than 86%. None DFR of these pigmente potatoes had signal peptide, obvious transmembrane structure region, we speculated that DFR might be a kind of hydrophilic protein which probably located in cytoplasm. We still found that α-helix and random coil were primary secondary structural components of DFR which belong to NADB-Rossmann superfamily.