Up-regulation of Squalene synthase in hairy root culture of Withania somnifera (L.) Dunal yields higher quantities of withanolides

Abstract The roots of Indian ginseng, Withania somnifera (L.) Dunal (Solanaceae) are extensively used in ayurvedic and other traditional medicines. The plant produces a steroidal lactone, withanolide which has multiple health benefits. Squalene synthase plays a central role in regulating the withanolide biosynthetic pathway in W. somnifera. The present approach investigated the up-regulation of squalene synthase in withanolides biosynthesis pathway in hairy roots. The higher expression of squalene synthase was noticed in hairy root line Ws9 which exhibited withanolide A (2.82 mg/g DW), withanolide B (1.34 mg/g DW), withaferin A (1.83 mg/g DW) and withanone (1.97 mg/g DW) on the 40th day of culture with 1.08 to 1.25-times higher, respectively. Semi-quantitative and quantitative polymerase chain reaction confirmed the incorporation and expression of squalene synthase in cultured hairy roots.