Abstract
Pretreatment in plants is recognized as a valuable strategy to stimulate plant defenses, leading to better plant development. This study evaluated the effects of validamycin A priming pretreatment on the antioxidative mechanisms involved in the response of two rice cultivars plants to salt stress. Salt stress elevated the accumulation of hydrogen peroxide (ROS) and the endogenous Malonaldehyde (MDA). Additionally, salt stress increased the activity of antioxidative enzymes (Peroxidase, POD; Catalase, CAT; Glutathione reductase, GR). Content of phenolic compounds was also increased by salt stress, while the content of Ascorbic Acid (ASA) showed the opposite effect. Pretreatment with 30 mu M validamycin A as seed soaking increase the activities of superoxide dismutase, peroxidase, polyphenol oxidase, and elevate the contents of flavonoids, ascorbic acid and tocopherol. The combined effect of validamycin A and salt treatment led to a higher activity of enzymatic antioxidants including Superoxide dismutase (SOD) and GR, and elevated the content of nonenzymatic antioxidants including ascorbic acid and tocopherol. Overall, we can conclude that exogenous validamycin A could alleviate the damage induced by salt stress, via reducing the deleterious effects of salinity on lipid peroxidation. These responses could be attributed to the ability of validamycin A to induce antioxidant defenses.