RNAi-mediated gene silencing of <i>WsSGTL1</i> in <i>W.somnifera</i> affects growth and glycosylation pattern

Sterol glycosyltransferases (SGTs) belong to family 1 of glycosyltransferases (GTs) and are enzymes responsible for synthesis of sterol–glucosides (SGs) in many organisms. <i>WsSGTL1</i> is a SGT of <i>Withania somnifera</i> that has been found associated with plasma membranes. However its biological function in <i>W.somnifera</i> is largely unknown. In the present study, we have demonstrated through RNAi silencing of <i>WsSGTL1</i> gene that it performs glycosylation of withanolides and sterols resulting in glycowithanolides and glycosylated sterols respectively, and affects the growth and development of transgenic <i>W.somnifera</i>. For this, RNAi construct (pFGC1008-<i>WsSGTL1</i>) was made and genetic transformation was done by <i>Agrobacterium tumefaciens</i>. HPLC analysis depicts the reduction of withanoside V (the glycowithanolide of <i>W.somnifera</i>) and a large increase of withanolides (majorly withaferin A) content. Also, a significant decrease in level of glycosylated sterols has been observed. Hence, the obtained data provides an insight into the biological function of <i>WsSGTL1</i> gene in <i>W.somnifera</i>.