Abstract:In order to understand the effect of illumination on the expression of glucosyltransferase gene in Bougainvillea glabra, the cyclo-DOPA-5-glucosyltransferase gene (cDOPA 5GT) was cloned from bracts. The results showed that the full length cDNA of cDOPA 5GT was 1 446 bp, encoding 482 amino acids. The bioin-formatics analysis showed that isoelectric point of cDOPA 5GT was 5.77, showing an acidic and hydrophilic transmembrane protein without signal peptide. The cDOPA 5GT protein had characteristic motifs of glucosyl-transferase, and the secondary structure was dominant of α-helices and random coils, and the amino acid sequence was less conserved. The results of qRT-PCR and spectrophotometry showed that the expression of cDOPA 5GT gene and betacyanin accumulation in plants decreased significantly under shading by qRT-PCR and spectro-photometry. Therefore, it was suggested that the synthesis of betacyanin was regulated by glucosyltransferase gene, and positively correlated with light time.