Over-expression of AtGSTU19 provides tolerance to salt, drought and methyl viologen stresses in Arabidopsis.

The plant-specific tau class of glutathione S-transferases (GSTs) is often highly stress-inducible and expressed in a tissue-specific manner, thereby suggesting its important protective roles. Although activities associated with the binding and transport of reactive metabolites have been proposed, little is known about the regulatory functions of GSTs. Expression of AtGSTU19 is induced by several stimuli, but the function of this GST remains unknown. In this study, we demonstrated that transgenic over-expressing (OE) plants showed enhanced tolerance to different abiotic stresses and increased percentage of seed germination and cotyledon emergence. Transgenic plants exhibited an increased level of proline and activities of antioxidant enzymes, along with decreased malonyldialdehyde level under stress conditions. Real-time polymerase chain reaction (PCR) analyses revealed that the expression levels of several stress-regulated genes were altered in AtGSTU19 OE plants. These results indicate that AtGSTU19 plays an important role in tolerance to salt/drought/methyl viologen stress in Arabidopsis.