Expression of Arabidopsis NDPK2 increases antioxidant enzyme activities and enhances tolerance to multiple environmental stresses in transgenic sweetpotato plants.

Transgenic sweetpotato ( Ipomoea batatas L. cv. Yulmi) plants expressing the Arabidopsis nucleoside diphosphate kinase 2 ( AtNDPK2) gene under the control of an oxidative stress–inducible peroxidase ( SWPA2) promoter (referred to as SN plants) were developed and evaluated for enhanced tolerance of SN plants under various abiotic stress conditions. The level of AtNDPK2 expression and NDPK activity in SN plants following methyl viologen (MV) treatment was positively correlated with the plant’s tolerance to MV. Interestingly, we observed that antioxidant enzyme activities such as peroxidase, ascorbate peroxidase, and catalase increased in MV-treated SN plants. In addition, SN plants showed enhanced tolerance to cold, high salinity, and drought stresses by an increase in the activity of H2O2 scavenging enzymes. These results indicate that overexpression of AtNDPK2 in sweetpotato might efficiently modulate oxidative stress from various environmental stresses. [ABSTRACT FROM AUTHOR]