Elevated expression of diosgenin-related genes and stimulation of the defense system in Trigonella foenum-graecum (Fenugreek) by cold plasma treatment

Atmospheric pressure plasma jets (APPJs) have been extensively studied for improving plant quality and yield. The effect of different working voltages (3500 V, 4000 V) as well as different exposure times (0.5, 1, 2 and 5 min) was evaluated using dielectric barrier discharge (DBD) plasma jet to determine the best combinations of treatment. The results revealed that there was a significant difference in all tested traits except for chlorophyll b and carotenoid content. The observed increasing activities of catalase (24%), glutathione peroxidase (53%), ascorbate peroxidase (86%) in comparison to control group, suggested that cold plasma treatment has a positive effect on the enhancement of Fenugreek defense system. The results also demonstrated that the total chlorophyll (88%) and protein (49%) content were significantly elevated. Further, the expression of Sterol side chain reductase, Squalene synthase, Squalene epoxidase, Cycloartenol synthase, and Sterol methyltransferase grew by 5.26, 3.42, 1.9, 4.19, and 3-fold, respectively, compared with the control group. This indicates cold plasma treatment as a promising approach to enhance the accumulation of diosgenin in Fenugreek. With respect to this fact that the classical breeding approach is a time-consuming and labor-intensive strategy, cold plasma could be an effective approach to improve plant traits.