Accumulation of H2O2and changes in activities of antioxidative enzymes andβ-1,3-glucanase in barley and meadow fescue leaves attacked byBipolaris sorokiniana

Abstract

The effects of Bipolaris sorokiniana inoculation on accumulation of hydrogen peroxide and changes in the activities of superoxide dismutase (SOD), catalase (CAT), non-specific peroxidase (PX) and β-1,3-glucanase enzymes in leaves of differentially resistant spring barley and meadow fescue were investigated in this study. Hydrogen peroxide accumulated slightly in inoculated barley leaves 24 hours after inoculation, and its accumulation after 48 hours of pathogenesis remained week around sites of infection. In leaves of fescue, which is more resistant to B. sorokiniana, accumulation of H2O2 was faster and stronger in comparison to barley. A slight increase in SOD activity was observed only in infected fescue. Catalase activity in infected barely leaves decreased significantly 48 hours after inoculation, while in fescue-infected plants CAT activity, following a slight decrease, remained similar to the control values. PX activity was considerable lower in inoculated barley leaves after 6 hours, but at 24 and 48 hours after inoculation its activity increased significantly compared to the control. In inoculated fescue leaves activity of PX was higher at 6 and 24 hours compared to the control, while at 48 hours PX activity was strongly inhibited. β-1,3-Glucanase activity in inoculated barley plants did not differ from that of the control, while in infected fescue leaves it increased significantly 48 hours after inoculation. Based on the results, we suggest that the strong accumulation of H2O2, changes in antioxidant levels, together with the significant increase of β-1,3-Glucanase activity in infected fescue leaves, plays an important role in fescue’s greater resistance to B. sorokiniana.