Abstract
The medicinal plant Hyoscyamus reticulatus L. is a rich source of hyoscyamine and scopolamine, the tropane alkaloids. The use of hairy root cultures has focused significant attention on production of important metabolites such as stable tropane alkaloid production. Elicitation is an effective approach to induce secondary metabolite biosynthetic pathways. Hairy roots were derived from cotyledon explants inoculated with Agrobacterium rhizogenes and elicited by iron oxide nanoparticles (FeNPs) at different concentrations (0, 450, 900, 1800, and 3600 mg L(-1)) for different exposure times (24, 48, and 72 h). The highest hairy root fresh and dry weights were found in the medium supplemented with 900 mg L(-1) FeNPs. Antioxidant enzyme activity was significantly increased in induced hairy roots compared to non-transgenic roots. The highest hyoscyamine and scopolamine production (about fivefold increase over the control) was achieved with 900 and 450 mg L(-1) FeNPs at 24 and 48 h of exposure time, respectively. This is the first report of the effect of FeNP elicitor on hairy root cultures of a medicinal plant. We suggest that FeNPs could be an effective elicitor in hairy root cultures in order to increase tropane alkaloid production.