[Identification and characterization of a flavonoid-3-O-glucosyltransferase gene from Saussurea involucrata].

The flavonoid-3-O-glucosyltransferas (3GT) is one of the most important enzymes for biosynthesis of plant secondary metabolites. In this paper, the homology analysis and gene special primers design were used. With the methods of modern molecular biology, the full-length gene of 3GT (GenBank Accession No. JN092127) which was cloned from Saussurea involucrata Kar. et Kir by RT-PCR and RACE. The cDNA sequence of 3GT consisted of 1548 bp open reading frame (ORF) encoding 516 amino acid, the deduced 3GT protein shared 91% and 89% identities with that of Fragaria x ananassa GT6, Manihot esculenta anthocyanidin 3-O-glucosyltransferase. Homology analysis showed that deduced 3GT protein has a glycosyltransferase signature domain PSPG-box. The transcripts of 3GT members were found mainly in leaves and callus. 3GT gene of S. involucrata was under the control of the cauliflower mosaic virus (CaMV) 35S promoter, homologous transformation used an Agrobacterium rihizogenes-mediated transformation system. The results on UV spectrophotometry showed S. involucrata callus after suspension culture that an average of total flavonoids on transgenic callus was 2.06 times higher than non-transgenic callus.