Improved growth and control of oxidative stress in plants of Festuca arundinacea exposed to hydrocarbons by the endophytic fungus Lewia sp.

The protective role of fungal endophytes in plants under stress by hydrocarbons is yet poorly understood. The influence of the endophytic fungus Lewia sp. on growth and oxidative stress control in plants of Festuca arundinacea exposed to a hydrocarbon mixture (HCM) was evaluated. Plants of F. arundinacea were inoculated or not with Lewia sp. to establish endophytic association. After 15 days, the plant growth, oxidative stress, and activity of antioxidant enzymes were analyzed in associated and unassociated plants. Then, both groups of plants were exposed for 7 days to a HCM (800 mg kg(-1)) in a model soil. The effect of the HCM was assessed in the plants through the same variables as mentioned above. Endophytic association was established after 15 days. The fungus enhanced plant growth, as well as H2O2 and malondialdehyde concentration, and decreased glutathione S-transferase (GST) activity. Lewia sp. decreased the H2O2 concentration in plants exposed to the HCM and increased the activity of superoxide dismutase and peroxidases, while significantly decreasing GST activity. This study demonstrates the positive role of Lewia sp. in promoting growth and alleviating oxidative stress in F. arundinacea exposed to hydrocarbons.