Transgenic potato plants expressing the cold-inducible transcription factor SCOF-1 display enhanced tolerance to freezing stress

Abstract

Potato (Solanum tuberosum) is a frost-sensitive species that is incapable of cold acclimation. Brief exposure to frost can significantly reduce yield, and hard frost can completely destroy entire crops. Thus, enhancing freezing tolerance by even a few degrees would considerably improve crop hardiness to frost damage. Transgenic potato plants expressing the soybean cold-inducible zinc finger transcription factor (SCOF-1) under control of the oxidative stress-inducible sweet potato peroxidase (SWPA2) promoter (designated as SF plants) were generated, and leaf discs and whole plants were evaluated for enhanced tolerance to cold and freezing conditions. SF plants were treated with 4 degrees C for 5days, and SCOF-1 expression positively correlated with tolerance to cold stress. SF plants treated with cold stress exhibited greater photosynthetic activity and total chlorophyll levels than those in cold-stressed non-transformed (NT) plants. During freeze-thaw treatment, lipid peroxidation levels in SF plants recovered to approximately prestress levels after 12h of recovery at 25 degrees C, whereas lipid peroxidation remained at an increased level in NT plants after the same recovery period. The results of our study indicate that freezing stress can be efficiently enhanced in potato by overexpressing SCOF-1.