Studies on Salt Tolerance of Transgenic Sweetpotato which harbors two Genes Expressing CuZn Superoxide Dismutase and Ascorbate Peroxidase with the Stress-inducible SWPA2 Promoter

In this study, some physiological indexes of leaves in transgenic sweetpotato (Ipomoea batatas L. cv. Yulmi), which harbors two genes CuZn superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) genes, with the stress-inducible SWPA2 promoter were evaluated under different concentrations of NaCl treatment. The results showed that physiological indexes were no remarkable differences without NaCl stress between the transgenic sweetpotato (TS) and the non-transformed sweet potato (NS). The activity of superoxide dismutase (SOD), ascorbate peroxidease (APX), peroxidase (POD) and catalase (CAT) in leaves of TS was always higher than NS under the same NaCl stress, respectively, and when the concentration NaCl with 100 mmol/L, the enzyme activities was the most significant difference especially. On the other hand, the root length of TS was longer than that of NS. And the decline range of chlorophyll and malonaldehyde (MDA) content in leaves of TS was lower than that of NS. All these results indicated that transgenic sweetpotato had the resistance to salt tolerance. Therefore, there would be a great significance in efficiently utilizing saline land and alleviating the energy crisis by developing and planting transgenic sweetpotato plants with salt tolerance.