Characterization of SBIP68: A Putative Tobacco Glucosyltransferase Protein and Its Role in Plant Defense Mechanisms

Plant secondary metabolites are essential for normal growth and development in plants ultimately affecting crop yield. They play roles ranging from appearance of the plants to defending against pathogen attack and herbivory. They have been used by humans for medicinal and recreational purposes amongst others. Glycosyltransferases catalyze the transfer of sugars from donor substrates to acceptors. Glucosyltransferases are a specific type of glycosyltransferases known to transfer glucose molecules from a glucose donor to a glucose acceptor (aglycone) producing the corresponding glucose secondary metabolite or glycone, in this case glucosides. It was hypothesized that SBIP68, a tobacco putative glucosyltransferase-like protein glucosylated salicylic acid. Salicylic acid is an essential plant defense secondary metabolite. SBIP68 was cloned and heterologously expressed in both prokaryotic and eukaryotic systems. Results from activity screening suggest that SBIP68 is a UDP-glucose flavonoid glucosyltransferase with broad substrate specificity. Further studies are required to fully characterize SBIP68