The antioxidant system (AOS) maintains the optimal concentration of reactive oxygen
species (ROS) in a cell and protects it against oxidative stress. In plants, the AOS consists of
seven main classes of antioxidant enzymes, low-molecular antioxidants (eg, ascorbate,
glutathione, and their oxidized forms) and thioredoxin/glutaredoxin systems which can serve
as reducing agents for antioxidant enzymes. The number of genes encoding AOS enzymes
varies between classes, and same class enzymes encoded by different gene copies may …