The effect of chitosan on induced resistance against Septoria of wheat

The septoria leaf spot caused by Zymoseptoria tritici، is one of the most destructive wheat diseases in the world, which causes lots of damage to this crop annually. The aim of this study was to investigate the effect of 0 and 200 ppm of chitosan on the expression of defense genes and antioxidant enzymes (peroxidase, catalase and ascorbate peroxidase) activity, in Koohdasht wheat cultivar (susceptible cultivar) in interaction with the pathogen. Therefore, two-week plants were sprayed with chitosan, and then treated plants along with control plants were inoculated with Z. tritici pathogen. Finally, the expression rate of PR1, PR2 and PR5 genes were examined using qRT-PCR technique at 0, 12, 24, 48, 96, and 240 hours after inoculation (hai). According to the results, disease severity reduced by about 55% in chitosan pre-treated plants compared to control. The results of qPCR showed that expression of mentioned genes increased in treated and control plants, but the expression of PR1, PR2 and PR5 genes increased by 7.5, 4.15 and 3.76 times more in treated plants compared to control in 24 hai, respectively. Comparing enzyme activity in chitosan pre-treated plants and control, indicates an increasing trend of peroxidase enzyme and a decreasing trend of catalase and ascorbate peroxidase in the first group of plants. The examined gene expression and antioxidants pattern changed in both groups of plants indicates the effectiveness of chitosan in inducing resistance against septoria leaf blotch in wheat.