Abstract
Dioscorea plants produce pharmaceutical diosgenin, which usually exists in plants in the form of saponins and has been a starting material for the production of steroids over seven decades. The first step of steroidal saponin biosynthesis from the corresponding aglycone is glycosylation by 3-O-sterol glycosyltransferase (S3GT), transferring the glycosyl from a sugar donor to the 3-OH position of the aglycone. In this study, a DzS3GT gene from Dioscorea zingiberensis was cloned and expressed in Escherichia coli, and the recombinant DzS3GT protein showed 3-O-sterol glycosyltransferase activity in vitro. Subcellular localization analysis revealed that the DzS3GT protein is located in the cytoplasm in rice protoplasts. The tissue profiles of DzS3GT differ from those reported SGT genes. DzS3GT is expressed strongly in leaves and very weakly in stems. The diosgenin 3-O-glucoside (trillin) content is much higher in the leaves than in other organs. The specificity of gene expression and saponins accumulation suggest that the biosynthesis of trillin may occur mainly in the leaves of D. zingiberensis. This is the first report of the cloning and biochemical characterization of a glycosyltransferase gene involved in the biosynthesis of diosgenin 3-O-glucoside in Dioscorea plants. In addition, the study provides a potential relevance to the biosynthesis and transport mechanism of steroidal saponins in Dioscorea plants.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
