Glutathione S-transferases (GSTs) are multifunctional proteins and forms major part, of plant cellular detoxification system and antioxidant enzyme network. Previously, a novel GST gene PvGSTU3-3 has been isolated from roots of Phaseolus vulgaris L. plants. The isoenzyme shows high antioxidant catalytic function and acts as hydroperoxidase, thioltransferase, and dehydroascorbate reductase. In the present study, with a view to investigate the biological function of PvGSTU3-3 a constitutive plant overexpression vector of PvGST3-3 was constructed and transferred into tobacco (Nicotiana tabacum. L. cv Xanthi) plants via A. tumefaciencs. The PvGSTU3-3 gene was successfully integrated into the genome of the transgenic tobacco lines as confirmed by Real time PCR and expressed in the transformants, validated through quantitative reverse transcription PCR. Three tobacco transgenic lines overexpressing PvGSTU3-3 tested for their salt tolerance (200mM NaCl) under in vitro conditions. All lines were more tolerant compared to wt plants, as demonstrated by the increased root length. These results suggest that PvGSTU3-3 isoenzyme can mediate physiological pathways that enhance salt stress tolerance
