Effect of Chitosan on the Expression Pattern of Some Pathogenecity Related Genes in Wheat Infected with Powdery Mildew

Powdery mildew, caused by Blumeria graminis f.sp tritici, known as a destructive disease of wheat worldwide that led to severe crop loss, annually. As chemical control is expensive and not ecologically safe, application of non-toxic chemicals to induce defense mechanism in plant host is desirable. In present study, induction of host resistance using chitosan on the expression of pathogenicity related gene was investigated. The expression rate of PR1, PR2 and PR5 in wheat treated with chitosan (0, 250 and 500 mg/L) were examined in factorial completely randomized design with three independent replications at 5 time courses using Real Time PCR technique Based on the results, the number of mildew colony in wheat leaves treated with chitosan 250 mg/L was decreased 42.3% than control. Results of qPCR indicated that in treated plants, the gene expression were increased significantly after infection, for all three genes. Maximum expression level of genes were observed at 12 hours after infection. This process was observed slowly in control plants but in treated plants induction of plant defense genes seemed more faster than control. Furthermore chitosan 250 mg/L induced plant defense gene more effectively than chitosan 500 mg/L. The results would support the idea that application of chitosan can play an important role in inducing systemic resistance in wheat plants against powdery mildew disease.