Assay of NPR1, MLO and BI-1 genes expression in susceptible wheat to powdery mildew after treatment with chitosan

Powdery mildew is one of the most important diseases of wheat that make yield damage annually. In recent years, the use of induction elicitors has been widely welcomed. Therefore, in this research in order to examine the ability of chitosan , Flat were selected as susceptible cultivar, and the leaves were sprayed with chitosan. Then treated plant together control plants were inoculated with Bgt pathogen.Finally, The expression rate of MLO, B-I1 and NPR1 genes was examined in using Real Time PCR technique Results showed that in both chitosan treated plants and the controls, rate of gene expression were increased after infection for all genes, So that, in the first hours after inoculation, treated plants showed NPR1 expression more rapidly than control. Maximum expression level of this gene was observed at 24 hours after infection. But, in treated plants, the expression rate of BI-1 and MLO were less than the control and they showed minimum expression at 24 hours after infection. These results indicated these genes by decreasing their expression rate in order to increase the level of active oxygen species causes induction of cell death in the plant to inhibition of fungal growth and development in the early stages after infection. The gene expression rate in plants treated with 250 mg/L was more indicative than those treated with chitosan 500 mg/L. Overall; results showed that chitosan could induce systemic resistance in susceptible wheat against powdery mildew in low concentration.