LAUSR

Abstract Effects of presowing seed treatment of Triticum aestivum L. and Tr. timopheevii Zhuk. wheat with bacteria Bacillus subtilis and B. thuringiensis were studied. Seedling growth, their generation of hydrogen peroxide, and the activities of pathogenesis-related (PR) proteins oxalate oxidase (OxO), peroxidase (PO), proteinase inhibitor (PI), and chitinase upon infection with the causal fungus of bunt Tilletia caries (DC.) Tul. were analyzed. It was found that Bacillus spp. bacteria attenuated the growth suppression of seedlings caused by the bunt infection and alleviated their affection by the pathogen. The found increase in bunt resistance was associated with the boost in the H 2 O 2 level, OxO and PO activities, and transcriptional activities of the chitinase TaChiI gene initiated by Bacillus spp. bacteria. The differences in activation of transcriptional activity of the proteinase inhibitor TaPI gene in soft wheat seedlings under the influence of B. subtilis and B. thuringiensis strains and their mixture were revealed. The results suppose that the wheat resistance to Til. caries may be formed through different paths, which may be related to the nature of the producer organism.