Combined effect of water stress and infection with the necrotrophic fungal pathogen Drechslera tritici-repentis on growth and antioxidant activity in wheat

Treatment with various concentrations (0, 5, 15 and 20%) of PEG was used to simulate water stress, followed by inoculation with Drechslera tritici-repentis (DTR) at two different points of time (6 and 72 h after the PEG treatment) in two DTR resistant (M-3 and Mv Magvas) and two sensitive (Bezostaya 1 and Glenlea) wheat varieties. The reduction in biomass production due to the PEG treatments was more pronounced in the shoots than in the roots. While in the case of Bezostaya 15% PEG reduced the level of infection, 20% PEG treatment lowered the tolerance level of M-3. DTR infection may be more efficient in inducing antioxidative defence systems than water stress. However, there was no direct correlation between the activity of the individual antioxidant enzymes and the drought or DTR tolerance of wheat plants.