Oilseed rape (Brassica napus) is an economically important crop. In temperate climate powdery mildew Erysiphe crucifertaum can reduce its yields dramatically. Nevertheless, cultivars resistant to this fungal disease have not been selected yet.

Glutathione plays an important role in plant resistance to oxidative stress. Reduced Glutathione (GSH) is involved in detoxification of ROS and toxic molecules, catalyzed by glutathione S-transferases (GSTs). Glutathione disulfide (GSSG) is formed during this process. Induction of the level of GSH and GST upon exposure to stress provide better protection of the plant cell. It is supposed that these mechanisms can also work during plant-fungus interactions, but they were never studied in oilseed rape, infected by E. crucifertaum.

B. napus plants, grown in the field and in the light chamber, were infected with powdery mildew. After 30 days there were severe signs of infection on most of the plants, however several individuals were less susceptible to it. Leaves of B. napus were used to measure the level of GSH, GSSG and GST by spectrophotometric assay.

The level of total glutathione was 2-3 times higher in plants with increased resistant to powdery mildew than in both severely infected plants and control plants that were not subjected to the infection. The GST activity in resistant and control plants was at the same level, however in susceptible plants it was 2-3 times lower.

Therefore, oilseed rape with naturally increased glutathione content can be used in the selection of resistant cultivars. GST and GSH genes should be also considered as targets for genetic engineering and genome editing.

Research was supported by grant of President of Russian Federation MK-1146.2020.11.