Alterations in antioxidant enzyme activities in rice plants treated with various abiotic inducers against the bacterial blight agent Xanthomonas oryzae pv. oryzae

Rice is the most important staple food in the world. Bacterial leaf blight of rice, caused by Xanthamonos oryzae pv. oryzae (Xoo), is a highly destructive and widespread disease. Chemical management approach to control this disease appears ineffective. In this experiment, the effects of three treatments of salicylic acid, potassium phosphite, and chitosan on susceptible rice plants inoculated with the bacteria were investigated  to assess the induction of resistance and activity of antioxidant enzymes including catalase (CAT), guaiacol peroxidase (GPX) and superoxide dismutase (SOD) during four days. The results showed that the highest and lowest activity of CAT was recorded in the chitosan and salicylic acid treatment, respectively. The maximum amount of catalase activity was 72 hours after inoculation.  Comparison of GPX and SOD enzyme activities at different sampling times  revealed that these enzymes reached their highest level at 48 and 72 hours after inoculation across all treatments, respectively. However, among different treatments, the highest activity of these enzymes was observed in plants infected with bacteria under potassium phosphite treatment. The findings show that potassium phosphite increases the activity of plant defense enzymes against the pathogen,  ultimately  reducing the symptoms of the disease.