The control of wheat defense responses during infection with Bipolaris sorokiniana by chitooligosaccharides

We studied the effects of low-molecular-weight water-soluble derivatives of chitin, chitooligsaccharides (ChOS) with a mol wt of 5–10 kD and the degree of acetylation of 65% on expression and molecular heterogeneity of peroxidase and the content of phytohormones in wheat plants differing in their resistance to the causal agents of root rots. Plant infection or their treatment with ChOS induced expression of the gene for anionic peroxidase and enhanced enzyme activity, and these processes depended on the degree of wheat resistance. They were more intense in the resistant cultivar. Treatment of susceptible plants with ChOS prevented a pathogen-induced drop in the cytokinin level, thus simulating defensive responses, which are characteristic of the resistant plants.