甜菜碱对稻瘟病的防效及其诱导水稻抗瘟性的分子机制OA

To elucidate the control effect of the rice metabolite betaine on rice blast and its resistance-inducing mechanism,exogenous betaine sprays at different concentrations and time points were applied to assess the resistance of rice cultivars against rice blast.The optimal concentration and timing for exogenous betaine application were screened.Furthermore,transcriptome sequencing was performed on rice treated with betaine under the optimal application conditions to analyze its resistance induction mechanism.The results showed that exogenous application of betaine effectively reduced the severity of rice blast in the susceptible rice varieties Huangkenuo and Lijiangxintuanheigu.The optimal relative control effect(40.06%)was achieved with a pretreatment of 20 mmol/L betaine applied 24 hours before inoculation with Magnaporthe oryzae.Transcriptome analysis of rice leaves pretreated with betaine indicated that differentially expressed genes were significantly enriched in the phenylpropanoid biosyn-thesis pathway at 0,24,and 48 hours.This treatment also induced the expression of lignin synthesis-related genes,including OsCCR17,OsCCR14,OsPAL3,OsCOMT15,OsCAD2,and the peroxidase gene OsPOX1.Additionally,lignin content and the activities of peroxidase and superoxide dismutase were significantly increased.These findings suggest that betaine induces the expression of genes involved in lignin synthesis and antioxidant enzymes,promotes lignin accumulation,and enhances antioxidant enzyme activity,thereby improving systemic resistance in rice against rice blast.