Over-expressing GsGST14 from Glycine soja enhances alkaline tolerance of transgenic Medicago sativa

Glutathione-S-transferases (GSTs) are ubiquitous enzymes that play a key role in stress tolerance and cellular detoxification. The GST gene GsGST14 selected from the gene expression profiles of Glycine soja under alkaline stress was transformed into alfalfa (Medicago sativa L.). Transgenic alfalfa plants showed 1.73-1.99 times higher GST activity than wild-type plants. Transgenic alfalfa grew well in the presence of 100 mM NaHCO3, while wild-type plants exhibited chlorosis and stunted growth, even death. There were marked changes in malondialdehyde content and relative membrane permeability caused by alkaline stress in non-transgenic lines compared to transgenic lines. The results indicate that the gene GsGST14 could enhance alkaline resistance in transgenic alfalfa.