A novel plant glutathione peroxidase‐like protein provides tolerance to oxygen radicals generated by paraquat in Escherichia coli

Citrus salt-stress associated protein (Cit-SAP) reveals significant sequence homology to mammalian glutathione peroxidase (GP). In an attempt to assign biological function to this protein, transformed E. coli cells expressing Cit-SAP were examined for their ability to tolerate free radicals formed by paraquat, an O2- radical forming agent. In the presence of paraquat, the survival rate of the transformed bacteria expressing Cit-SAP was much higher as compared to the wild-type bacteria. The results support the assumption that Cit-SAP is a plant GP-like protein which participate in the enzymatic system aimed at scavenging oxygen free-radicals in plants.