Transgenic Tobacco Over expressing Cytosolic Superoxide Dismutase Exhibit Enhanced Tolerance To UV-B Stress

Stress leads to generation of reactive oxygen species (ROS) in living cells, which are scavenged by antioxidant enzymes. Effect of UV-B stress on transgenic tobacco (Nicotiana tabacum cv. Xanthi) overexpressing cytosolic superoxide dismutase (AhCuZnSOD) and untransformed control plants were compared. Transgenic tobacco plants exhibited higher levels of total antioxidant enzyme activities, lower level of malonyldialdehyde content and hydrogen peroxide accumulation under stress conditions in comparison to the untransformed control (UC) plants. Our analysis revealed that antioxidant enzyme leads to increase in the total activity of the antioxidant ezymes and thus improve UV stress tolerance in transgenic plants.