Alleviation of copper phytotoxicity by acetylsalicylic acid and nitric oxide application in mung bean involves the up-regulation of antioxidants, osmolytes and glyoxalase system

The study assessed the individual and interactive role of acetylsalicylic acid (ASA) and nitric oxide (NO) against excess copper (Cu) concentrations. Excess Cu significantly reduced growth and photosynthesis, although the application of ASA and NO significantly mitigated the reduction with much visible effect in their combination. The oxidative effects of Cu have been evident as increased reactive oxygen species (ROS) production, resulting in increased malondialdehyde (MDA) and reduced membrane stability index (MSI). Both ASA and NO reduced oxidative damage obvious as reduced MDA and lipoxygenase (LOX) down-regulation. Up-regulation of enzymatic and non-enzymatic antioxidants due to ASA and NO application contributed to the quick elimination of excess ROS. Oxidative effects of excess Cu were mitigated by osmolyte accumulation, up-regulation of the γ-Glutamyl kinase (γ -GK), glyoxalase, and down-regulation of proline oxidase (PROX). Reduced Cu accumulation in our study showed the crosstalk effect of ASA and NO resulting in the protection of mung bean growth against the damaging effects of Cu.