Overexpression of an alfalfa glutathione S-transferase gene improved the saline-alkali tolerance of transgenic tobacco.

Abiotic stresses restrict the productivity and quality of agricultural crops. Glutathione S-transferase (GST) utilizes glutathione to scavenge reactive oxygen species (ROS) that result from abiotic stresses. This study aimed to determine the expression pattern of the gene and its effects on saline-alkali tolerance. , from alfalfa ( 'Zhaodong'), was transformed into transgenic tobacco () and overexpressed to determine its effects on saline-alkali tolerance. The gene products in alfalfa localized to the cytoplasm and the transcript levels were higher in the leaves than the roots and stems. Expression was strongly induced by cold, drought, salt and saline-alkali stresses as well as abscisic acid (ABA) treatments. The transgenic tobacco lines had significantly higher transcription levels of the abiotic stress-related genes and higher GST activity than the wild types. Transgenic tobacco lines with saline-alkali treatments maintained their chlorophyll content, showed improved antioxidant enzyme activity and soluble sugar levels, reduced ion leakage, O , HO accumulation and malondialdehyde content. Our results indicate that overexpression of could improve resistance to saline-alkali stresses by decreasing the accumulation of ROS and increasing the levels of antioxidant enzymes. Furthermore, they suggest that could be utilized for transgenic crop plant breeding.