Expression analysis of key genes involved in terpenes biosynthesis and antioxidant enzymes in hairy root of Origanum vulgare elicited with methyl jasmonate

In the current study, the effects of three levels of methyl jasmonate concentration were studied on the hairy root cultures of Origanum vulgare. For this purpose, A. rhizogenes strain A13 was used to create stable hairy root lines from shoot explants. In this regard, two co-cultivation media (MS and modified MS), two inoculation times (5 and 10 min) as well two concentrations of acetosyringone (0 and 100 µM) were attentively studied. Propagated hairy roots were treated with different concentrations of methyl jasmonate (0.1, 0.2, and 0.5 µM). Sampling after 24 and 96 h of methyl jasmonate application, the activities of antioxidant enzymes were evaluated. Moreover, the gene expression level of OvDXR and OvTPS2, two important genes involved in the MEP pathway, were studied using real-time PCR technique. The highest transformation rate was observed in the explants cultured modified MS which were incubated in the bacterial suspension with acetosyringone for 10 minutes. The biomass of hairy root cultures was significantly decreased by methyl jasmonate compared to control samples. In addition, the results indicated that the concentration of methyl jasmonate, harvesting time, and their interactions significantly affected the activity of catalase, peroxidase, and SOD enzymes. The expression of OvDXR significantly increased after 24 h of treatment by 0.2 µM methyl jasmonate, while in the same sample, the expression of OvTPS2 decreased noticeably. The expression of OvDXR and OvTPS2 genes was significantly increased by 0.5 µM methyl jasmonate after 96 h. The application of methyl jasmonate as an efficient elicitor in hairy root culture system of O. vulgare is suggested for the production of valuable metabolites.