Isolation and functional characterization of BrUGT gene encoding a UDP-glycosyltransferase from Chinese cabbage (Brassica rapa)

Glycosyltransferases are enzymes (EC 2.4) that catalyze the transfer of monosaccharide moieties from activated nucleotide sugar to a glycosyl acceptor molecule which can be a carbohydrate, glycoside, oligosaccharide, or a polysaccharide. In this study, a UDP-glucosyltransferase cDNA was isolated from Brassica rapa using a rapid amplification of cDNA ends (RACE) and subsequently named BrUGT. It has a full-length cDNA of 1,236 bp with 119 bp 5′-untranslated region (UTR), a complete ORF of 834 bp encoding a polypeptide of 277 amino acids (31.19 kDa) and a 3′-UTR of 283 bp. BLASTX analysis hits a catalytic domain of Glycos_transf_1 super family (cl12012) that belongs to the Glycosyltransferases group 1 with tetratricopeptide (TPR)regions located between 165 to 350 bp. Expression analysis showed high mRNA transcripts in pistil, followed by petal, seed and calyx of flower. Moreover, expression analysis of BrUGT in Chinese cabbage seedlings under stresses of cold, salt, PEG, H2O2, drought and ABA showed elevated mRNA transcript. Furthermore, when BrUGT gene was transformed into rice using pUbi-1 promoter, overexpression was evident among the T1 plants. This study provides insights into the function of BrUGT in plants.