Evaluation of RBOH gene expression and physiological responses of Citrullus colocynthis under nickel stress conditions

Respiratory Burst Oxidase Homologue (RBOH) is involved in the perception and response to environmental stresses in plants by producing reactive oxygen molecules. In the present study, the expression of RBOH gene and morphophysiological parameters of Citrullus colocynthis in different concentrations of nickel chloride were investigated. 15-day-old seedlings were treated with different concentrations of nickel chloride (0, 150, 300 and 450 µM). The results showed that with increasing nickel chloride concentration, shoot and root length, shoot and root dry weight and relative water content decreased and the activity of superoxide dismutase and catalase, and content of proline, malondialdehyde and hydrogen peroxide increased significantly compared to the control group. Also, in treated plants, the uptake of elements such as manganese and zinc decreased. The expression level of RBOH gene also increased with increasing the amount of nickel chloride compared to untreated plants. According to the results of this study, nickel metal stress induces the expression of RBOH gene in C. colocynthis.