Subin O. Induced Resistance of Strawberry Plants (Fragaria ananassa Duch.) Against Main Phytopathogens

The dissertation is devoted to the study of eliciting properties and direct biocidal action of chitosan of various biological origins against the main phytopathogens of strawberry. The peculiarities of induction of the corresponding reactions of F. аnanassa in response to treatment with chitosan solutions are shown. The induction of reconstruction of secondary metabolism for the influence of salicylic acid with an active synthesis of terpenoids and conjugates of oxycoric acids with the properties of nonspecific growth regulators is established. The peculiarities of the monosaccharide composition of chitosan derived from Agaricus bisporus are shown. The features of the level of relative expression of PR-proteins PR-1, PR-2a (β-1,3-glucanase), PR-2b (endo-β-1,4-glucanase), and PR-3 (chitinase) of F. ananassa plants depending on the biological origin of chitosan, time after treatment is revealed. The relative level of gene data expression under plant treatment with low molecular weight chitosan was higher compared to high molecular weight one. The differences in the response reactions of the strawberry for processing low molecular weight chitosan and high molecular weight one are established. For processing plants with low molecular weight chitosan in leaves for 12 hours, the number of common phenols and antioxidants increased by 1.9 and 3.2 times, respectively. Unlike low molecular weight chitosan, a solution of high molecular weight one polymer caused a sharp decrease in the content of free and weakly linked with cellular walls phenolic compounds. The peculiarities of accumulation of ellagic acid as one of the key components in the system of primary protective reactions of plants against pathogens are established. Daily oscillations of the parameters of phenolic compounds are detected, in particular ellagitannins and flavonoids in F. ananassa leaves, as one of the main mechanisms in the adaptation of plants to stress factors. The dynamics of the species composition of phylloplane, rhizoplane, and rhizosphere mycobiota of the garden strawberries for the actions of low molecular weight chitosan and high molecular weight one are determined. The differences in the influence of chitosanes of different biological origins on the group of micromycetes are shown. It is proved that the chitosan complex with sorbic acid has a prolonged antibacterial effect on Pectobacterium carotovorum subsp. сarotovorum and Clavibacter michiganensis subsp. sepedonicus and antifungal effects for Fusarium spp. and Alternaria spp.