Cloning and expression trait of UDP-glucose:flavonoid 3-O-glucosyltransferase gene (UF3GT) in turnip
Anthocyanin is a class of important secondary metabolites in plants. UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) is a committed catalytic enzyme in the late stage of anthocyanin biosynthesis. BrUF3GT1 and BrUF3GT2 genes were cloned by reverse transcription polymerase chain reaction (RT-PCR) method from ‘Tsuda’ and ‘Yurugi Akamaru’ turnips. The open reading frame (ORF) of BrUF3GT1 and BrUF3GT2 genes contained 1407 bp encoding proteins of 468 amino acids. Amino acid sequence analysis showed that BrUF3GT1 and BrUF3GT2 had 87% identity to UF3GT of Arabidopsis thaliana, and the glycosyltransferase protein family domain was in the amino acids sequence from 16 to 453. The nucleotide sequence of BrUF3GT1 and BrUF3GT2 genes showed only seven nucleotide differences, and one common deduced amino acid sequence. The northern blotting results showed that the expression of BrUF3GT1 and BrUF3GT2 genes could be induced by irradiation of ultra-violet A (UV-A), and the expression of the genes was correlated with light-exposure time. The 51.88 and 51.89 KDa proteins of BrUF3GT1 and BrUF3GT2 were successfully purified after prokaryotic induced expression.
Key words: Turnip, UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) gene, gene clone, sequence analysis, gene expression.