The virulence of the causal agent of Septoria nodorum blotch of wheat pathogenic fungus Stagonospora nodorum Berk. is caused by the presence of necrotrophic effectors (SnTox). Isolates infect wheat varieties that carry susceptibility genes (Snn) corresponding to toxins in the genome. SnTox-Snn interactions are mirror images of classical gene-for-gene interactions and lead to the development of disease. In the present work, we have studied SnTox-Tsn1 and SnTox1-Snn1 interactions resulting in development of necrosis and chlorosis in wheat plant tissues with the formation of extensive lesions. It is assumed that the multiplicity of SnTox-Snn reactions can be carried out through the regulation of transcription of plant susceptibility genes. The aim of the work was to study the transcriptional activity of the Tsn1 and Snn1 susceptibility genes in wheat varieties with varying degrees of resistance to S. nodorum. Alleles of the Tsn1 and Snn1 susceptibility genes were identified by PCR in 12 varieties of winter and spring wheat. Seedling resistance was determined for all samples by the lawns method. Then five varieties were selected for further study. The resistance of the Omskaya 35 variety, which carries a single dominant Snn1 allele, was determined by the suppression of transcription of the Snn1 gene by almost 2 times. The resistance of the Yubileynaya 100 variety, which carries two dominant alleles Tsn1/Snn1, was determined by suppression of transcription of the Tsn1 gene by 8 times. The resistance of the Esaul and Yermak varieties, as well as the susceptibility of the Zhnitsa variety, were determined not only by the transcriptional activity of the Tsn1 gene, but possibly by other factors. A statistically significant positive correlation of 0.97 was found between the transcription level of the Tsn1 gene and the resistance of the variety.
Molecular screening of susceptibility genes Tsn1 and Snn1 in the accessions of genus Triticum L. for resistance to the toxins SnToxA and SnTox1 from the Stagonospora nodorum
