Salt stress tolerance of transgenic alfalfa with the GsbZIP33 gene

In the present study,the physiological and biochemical indicators of two salt-tolerant transgenic lines (b32 and b77) and the wild type alfalfa were compared after 15 days treated with 200 mmol·L-1NaCl, including soluble sugar content, the activities of catalase (CAT),peroxidase (POD) and superoxide dismutase (SOD), photosynthetic rate (Pn) and the content of K+ and Na+. Compared with the wild type plants, the soluble sugar content of the two transgenic lines increased by 48.8% and 39.6%, respectively, the SOD activities increased by 71% and 89 %, CAT activities increased by 21% in b32 and 13% in b77, POD activities increased by 32.9% and 34.1%, Na+ contents decreased by 57% and 44% and K+ contents increased by 23% and 13%, respectively. The photosynthetic rate of transgenic plants increased by 2.4 times compared with the wild type plants. This study demonstrated that the transgenic alfalfa (b32 and b77) had a greater tolerance of saline stress compared with non-transgenic plants.