抄録
Low temperature have been broadly applied for storage technique of various vegetable and crops. Sweetpotato is one of the most popular crops grown in tropical and temperature regions. Because sweetpotato, originated from semi-tropical plants, is susceptible to cold stress, severe chilling stress by itself causes deterioration and/or irreversible damage in sweetpotato tuber tissues. However, mechanisms involved in physiological and biochemical changes of sweetpotato under chilling stress remain unclear. Thus, we focused on the gene expression profiles of cold stress-responsive transcriptional factors and carbohydrate metabolisms of sweetpotato in response to chilling stress. A sweetpotato homolog of Drought Responsive Element Binding factor (swDREB) is induced in sweetpotato within 6 h after treatment of chilling stresses. The expression of swDREB under chilling stress was maintained until 3 d. Chilling stress sequentially upregulated the expression of β-amylase (β-AMY) and trehalose-6-phosphate phosphatase (TPP). Increase of amylase activity and sugar content was also observed in sweet potato under chilling stress, These results suggest that swDREB mediates the expression of β-AMY and TPP via a cold stress-responsive transcription factor cascade, leading to degradation of starch in sweetpotato tuber and accumulation of maltose and trehalose.
