Expression of yeast SOD2 in transgenic rice results in increased salt tolerance

Agricultural productivity is severely affected by soil salinity. One possible mechanism by which plants could survive salt stress is to remove sodium ions from the cytosol via plasma membrane Na+/H+ antiporters. In the present study, we demonstrated that expressing the plasma membrane Na+/H+ antiporter SOD2 from yeast (Schizosaccharomyces pombe) in transgenic rice increased salt tolerance. These transgenic plants accumulated more K+, Ca2+, Mg2+ and less Na+ in their shoots compared with those of non-transformed controls. Moreover, measurements on isolated plasma membrane vesicles derived from the SOD2 transgenic rice plant roots showed that the vesicles had enhanced P-ATPase hydrolytic activity. Furthermore, the transformed rice plants maintained higher levels of photosynthesis and root proton exportation capacity, whereas reduced ROS generation. Physiological analysis suggested that transgenic rice plants might employ multiple mechanisms to improve their salt tolerance under salt stress conditions.