The StDREB1 transcription factor is involved in oxidative stress response and enhances tolerance to salt stress

Abstract

We have shown previously that the potato dehydration responsive element binding (StDREB1) transcription factor plays an important role in regulating and improving salt and drought stress-response genes in potato plant. To further characterize StDREB1 involvement in stress response, we focuse here on the investigation of the StDREB1 target genes by an Electrophoretic mobility shift assay. The data obtains indicated that the StDREB1 protein can bind to both GCC and DRE boxes in the promoter sequence of target genes, suggesting that this transcription factor may play a key role in the response to abiotic- and biotic-stresses by the activation of the DRE- and GCC- mediated signaling pathways. In a second step, since some DREB factors were related to the oxidative stress response, we showed that H2O2 treatment led to a significant increase of StDREB1 expression in wild- type potato plants. Moreover, the analysis of the oxidative stress response of StDREB1 transgenic potato plants revealed lower levels of H2O2 and malondialdehyde than wild-type control plants submitted in vitro to salt stress. An increase in the antioxidant enzyme activities including superoxide dismutase (SOD) and catalase was also observed in StDREB1 plants. In addition, an enhanced expression of the Cu/Zn SOD gene was noticed in these StDREB1 transgenic plants, cultivated under salt stress conditions. These results suggest that StDREB1 plays an essential role in the regulation of stress-response by regulating the oxidative stress response. The involvement of this transcription factor in the activation of osmoprotectant synthesis was also confirmed.