Priming with salicylic acid induces defense against bacterial blight disease by modulating rice plant photosystem II and antioxidant enzymes activity

摘要

Bacterial blight is a serious threat to rice production, causing about 50% reduction in grain yield. In the present investigation, we have used chlorophyll fluorescence technique to assess the structural and functional characteristics of chloroplast in a susceptible rice variety, treated with different concentrations of salicylic acid (a multifaceted hormone) and infected withXanthomonas oryzaepv. oryzae. Results from various physiological (chlorophyll content and chlorophyll fluorescence) and biochemical parameters (catalase, superoxide dismutase, peroxidase and polyphenol oxidase activities) and disease index, suggested that treatment of plants with twomM salicylic acid has provided best protection to plants from bacterial blight disease thereby inducing resistance against the pathogen. The fieldtrial has also been carried out, and in comparison to diseased plants, an increase in different yield parameters was observedin diseased plants treated with twomM salicylic acid. So, salicylic acid treatment alters the physiology of plants and provides a useful way of crop protection, especially in thecase of bacterial blight. The study has been carried out in the net house and confirmed underthefield condition, on how priming with salicylic acid inducesdefenceagainst BB disease (by modulating photosystem II activity) and the effects of salicylic acid treatment on rice grain yield of BB infected plants.