The effect of salicylic acid and vanil-line on wheat resistance to Cochliobolus sativus
The influence of salicylic acid (SA) and vanillin on the development of phytopathogen Cochliobolus sativus, causing dark brown spot of wheat has been studied. The results indicate that the immunomodula-ting effect of SA and vanillin towards hemi-biotrophic pathogen C. sativus depends on their concentrations. The 7-day-old wheat seedlings were treated with SA and vanillin 24 hours later were infected with the fungus (C. sativus). The treatment of wheat with 0.1-0.5 mM SA slightly reduced the disease severity. SA at a concentration greater than 2 mM showed high inducing effect against the fungus. Application of 5 mM salicylic acid reduced severity of disease caused by C. sativus to 50 % and it was connected with activation of peroxidase activity. The application of 0.1-0.5 mM vanillin had not reduced fungal infection in wheat. Immunomodulating effect of vanillin enhanced with increasing concentration of 1.0 to 15 mM. Pretreatment of wheat leaves with 10 mM vanillin reduced severity of the disease suppressing necrosis associated with susceptibility to C. sativus by 40 % and increasing peroxidase activity. It is suggested that the inducing effect of vanillin was associated with the regulation of the activity of antioxidant enzymes. Thus, induced resistance in wheat treated by SA and vanillin to hemibiotrophic pathogen C. sativus seems to depend on enhanced antioxidant capacity.