The impacts of interaction between NO and H2O2 on Astrgalus adsurgens response to Embellisia astragali

A disease susceptible cultivar of Astrgalus adsurgens was applied with exogenous NO and AsA after inoculating Embellisia astragali. Disease incidence (DI), disease severity index (DSI), H2O2 concentration, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity were analyzed to investigate the interaction between NO and H2O2 during disease development. Compared with control plants, DI and DSI of NO treatment plants significantly decreased (P0.05). AsA treatment weakened the effects of NO. NO could induce more H2O2 during the earlier period. However, NO delayed H2O2 accumulation during the later period that concentration of H2O2 was relatively higher. The increasement of SOD, POD and CAT activity induced by NO was inhibited by AsA. The results showed that exogenous NO implication could improve the disease resistance of A.adsurgens. NO may interact with H2O2 and exert its effect by modulating the endogenous H2O2 level.