The effects of Silver Nanoparticles on the expression pattern of Limonene Synthase gene in Cell culture in Carum carvi L.

European black cumin (Carum carvi L.) is an important species of the Apiacea family that has valuable terpene compounds. The aims of this study were, to determine the effect of different hormonal treatments on the production of callus from leaf and root explants and also to select the best explant and hormonal treatment for cell culture, and then to investigate the effect of silver nanoparticles on the stimulation of the production of secondary metabolites and the expression of the Limonene synthase gene in callus was obtained from cell culture. First, the effect of 6 hormone treatments in MS culture medium on the callus produced from two explants (leaf and root) were investigated by measuring three quantitative and qualitative traits in each of the treatments. Considering the above traits, leaf explant in MS2 hormone treatment, which included IBA (0.1 mg/l), 2IP (0.5 mg/l) and BA (0.5 mg/l), were identified as superior explant and hormone treatment. To continue the studies, the calluses obtained from the superior explant on the superior hormone treatment were transferred to the cell culture medium containing MS culture medium without agar. Then the samples were placed in a shaker at 120 rpm under dark conditions at a temperature of 24°C. After multiplying the callus and reaching the desired growth, the samples were treated with silver nanoparticles in two concentration of 50 and 100 mg/l, and samples were taken from the calluses at zero, 24 and 48 hours after the treatment. The data obtained from GC and GC/MS and the results of limonene synthase gene expression showed that silver nanoparticles as a non-living stimulus by intensifying defense responses in black cumin, caused a change in the synthesis rate of secondary  metabolites such as Limonene, Carvone, Carvacrol, Thymol, p-Cymene and γ-Terpinene and also increased the expression of Limonene synthase gene.