Effect of Yeast Extract on h6h Gene Expression and Tropane Alkaloids Production in Atropa belladonna L. Hairy Roots

Plant alkaloids, are one of the largest groups of pharmaceutical metabolites. Scopolamine and atropine are most common tropane alkaloids in Atropa belladonna L. with great application in pharmaceutical industry. Phytochemical biosynthetic pathways induction via various elicitors is an effective strategy for increasing the production of valuable substances. Therefore, in this research effect of yeast extract were studied on expression of h6h gene, antioxidant enzymes activity and production of tropane alkaloid in A. belladonna hairy roots. Hairy roots of A. belladonna were obtained from cotyledonary leaf explants by A7 strain of Agrobacterium rhizogenes . Polymerase chain reaction (PCR) analysis with specific primers confirmed the insertion of rolB in putative transgenic hairy roots genome. Different concentrations of yeast extract (YE) (0, 0.5, 1 and 1.5 mg/L) at different exposure time (24 and 48 h) were used as elicitor. Scopolamine and atropine content and activity of antioxidant enzymes such as guaiacol peroxidase, ascorbate peroxidase and catalase increased and expression of h6h (hyoscyamine 6 beta-hydroxylase) gene in elicited hairy roots were investigated. High concentration of YE decreased the growth of hairy roots but increased the atropine content compared to the control. According to the results, the highest content of scopolamine (9.21%) and atropine (43.39%) which were 9 and 5 fold than control, were obtained by 1 and 1.5 mg/L YE at 48 h exposure time, respectively. The results demonstrated that YE can be used as effective elicitor to increase tropane alkaloids production in hairy root cultures of A. belladonna .