Exploring the Role of TaERF4a in Enhancing Drought Tolerance and Regulating Dehydrin WZY1-2 Gene Expression in Wheat

Dehydrins (DHNs) belong to the second family of late embryogenesis abundant (LEA) proteins, which are widely distributed in plants. We cloned a SK₃-type DHN gene named <i>WZY1-2</i> in Zheng yin 1 cultivar of <i>Triticum aestivum</i>. An ERF-type transcription factor TaERF4a was found to be involved in the regulation of the dehydrin <i>WZY1-2</i> gene in our last report. The stress-responsive ability and dual-luciferase assay demonstrated that TaERF4a positively regulates <i>WZY1-2</i> gene transcription under stress conditions. In this study, we further characterized the role of the transcription factor TaERF4a in plant drought tolerance. <i>Arabidopsis thaliana</i> heterologously overexpressing <i>TaERF4a</i> exhibited higher survival rate, increased superoxide dismutase (SOD) activity, elevated proline and chlorophyll content, and reduced malondialdehyde (MDA) content under drought conditions. Conversely, silencing <i>TaERF4a</i> in Chinese spring wheat using the virus-induced gene silencing (VIGS) method increased the sensitivity of plants to drought stress. Furthermore, we identified the specific binding site of TaERF4a in the <i>WZY1-2</i> promoter. Electrophoretic mobility shift assay (EMSA) and dual-luciferase reporter assay demonstrated that TaERF4a activates the expression of the <i>WZY1-2</i> dehydrin gene through binding to the DRE <i>cis</i>-element in its promoter. Taken together, the results of our study indicate that TaERF4a positively regulates the expression of the dehydrin <i>WZY1-2</i> gene and enhances drought tolerance in plants.