Abstract: The dihydroflavonol-4-reductase (DFR) is an important enzyme in plant secondary metabolites and catalyzes the key step in the biosynthesis of anthocyanins. DFR gene (GenBank Accession JN092126) was cloned from Saussurea involucrata Kar. et Kir. by RT-PCR and RACE. The cDNA sequence of DFR was consisted of 1 029 bp open reading frame (ORF) encoding 343 amino acid, the deduced DFR protein has high homology with S.medusa (92% identity). Homology analysis showed that deduced DFR protein has the special domain regioselectivity towards NADPH. DFR gene of S.involucrata was under the control of the cauliflower mosaic virus (CaMV) 35S promoter, homologous transformation was conducted using an Agrobacter-ium rihizogenes-mediated transformation system. The results of UV spectrophotometry showed that Sinvolucrata callus after suspension culture had an obviously higher average content of total flavonoids than non-transgenic callus. This study will improve the products of medicinal compositions and realize the synthesis of anthocyanins in S.involucrata.

Key words: Saussurea involucrata, dihydroflavonol-4-reductase, homoosis, flavonoids