Butsenko L. Biological properties and microbe-plant interactions of the causative agent of basal bacteriosis of wheat agrophytocenosis

The dissertation is devoted to the systematic study of the distribution and biological properties of Pseudomonas syringae pv. atrofaciens and its changes under pesticide action, the ability of this pathogen and its lipopolysaccharides (LPS) to affect physiological and biochemical processes and induce changes in plant genetic material. P. syringae pv. atrofaciens is widespread in wheat agrophytocenoses as a pathogen, epiphyte and agent of diseases of segetal vegetation. The population of the pathogen is homogeneous in phenotypic and genotypic properties. Strains widespread in wheat agrophytocenoses belong to serological groups II, IV, V, VI, which made it possible to develop a polystrains antiserum for identification of the pathogen. The use of pesticides does not allow to control the pathogen effectively, however, widely used in cereal crops tribenuron-methyl + trifensulfuron-methyl and benomyl, thiophanate-methyl, fludioxonil are characterized by mutagenic effects on the pathogen, causing an increase in the number of StrR mutations. Alpha-cypermethrin and tribenuron-methyl + trifensulfuron-methyl induce a 10 – 100-fold increase in the frequency of morphological dissociation of P. syringae pv. atrofaciens with the formation of R-forms, which are characterized by an increased ability to form a biofilm while maintaining virulence properties. LPS P. syringae pv. atrofaciens shows antimutagenic activity in the bacterial test system, however, in the plant test system with A. cepa LPS of the pathogen cause an increase in the frequency of chromosomal aberrations, which may be due to the oxidative stress induced by this biopolymer in plant cells. P. syringae pv. atrofaciens increases the activity of antioxidant components, reduces the content of photosynthetic pigments, inhibits the processes of photosynthesis in wheat. Inactivated cells and the LPS of P. syringae pv. atrofaciens cause inhibition of division and proliferation of wheat callus cells and can be used in selection for resistance to the pathogen.