Ectopic Overexpression of Teff Grass (Eragrostis tef) Phi-class Glutathione S-transferase 1 (EtGSTF1) Enhances Prokaryotic Cell Survivability against Diverse Abiotic Stresses

The glutathione S -transferases (GSTs) are encoded by a large gene family and well conserved in all living organisms; however they have evolved and are classified clearly according to each kingdom. GSTs are a dimeric protein that has been reported to maintain redox homeostasis in cells, and to protect organisms against oxidative damage. Recently, we isolated a GST coding gene from stress-treated teff grass ( Eragrostis tef ) and identified it as a plant-specific phi class GST ( EtGSTF1 ) possessing conserved phi class-specific GST N- and C-terminal domains, GSH binding site, substrate binding pocket, and dimer interface. We found that overexpression of plant-specific phi class EtGSTF1 confers diverse abiotic stress tolerances including salt, osmotic, and heat stresses in E. coli which does not possess phi class GSTs. In addition, EtGSTF1 expression helps the E. coli cells tolerate arsenic (As)-induced cell toxicity. Collectively, although plantae and prokaryotae have differentiated a few billions of years ago, the plant-specific phi class EtGSTF1 could protect prokaryotic organisms by detoxification of molecules under diverse abiotic stresses.