Salicylic and succinic acids as inducers of phytoimmunity in winter wheat for the management of powdery mildew (Blumeria graminis (DC) Speer f. sp. tritici).

Background: Growth regulators play an important role in activating the main signal transduction pathways in response to stress, and their activity is key in the general mechanism to understanding the formation of phytoimmunity under biotic stress. The study investigates the specificity of stress-protective reactions in winter wheat varieties with varying degrees of sensitivity to the phytopathogen Blumeria graminis (DC) Speer f. sp. tritici, and determined the effectiveness of exogenous salicylic and succinic acids as inducers of resistance to powdery mildew.

Results: Exogenous application of 0.1 mM salicylic acid induced stress-protective reactions in the resistant wheat, characterised by increased ethylene release, and phenylalanine amino-lyase and ascorbate peroxidase activity in the flag leaves. These steps help optimize its physiological state and productivity by preserving the integrity of cell membranes and its chlorophyll content. Exogenous succinic acid at a concentration of 0.1 mM also led to the activation of protective antioxidant systems, which did not have a positive effect on plant physiology or productivity during infection. The susceptible variety of winter wheat was unable to mobilize the necessary stress-protective systems, regardless of salicylic or succinic acid treatment, resulting in the spread of infection and reduced productivity.

Conclusions: The resistance of winter wheat to phytopathogen damage (Blumeria graminis (DC) Speer f. sp. tritici) is determined by the capacity of the plant to mobilize stress-protective reactions and optimize its metabolism. Salicylic acid (0.1 mM) effectively enhances plant defence systems, thus improving plant physiology and productivity during the spread of powdery mildew.