| To elucidate the functional mechanism of the GmMYB46 gene, a member of the soybean MYB transcription factor family, in response to drought stress, quantitative real\|time PCR was used to analyze its expression levels in soybeans subjected to PEG\|simulated drought conditions. The coding sequence of the GmMYB46 gene was cloned to construct an overexpression vector, and the wild Arabidopsis was transformed via Agrobacterium. Growth patterns of transgenic and wild Arabidopsis plants under normal cultivation and drought stress were observed. Leaf electrolyte leakage, soluble sugar, proline content and antioxidant enzyme activity were measured, and stomatal aperture was observed and compared. The results showed that drought stress significantly upregulated GmMYB46 in roots and leaves, increasing its expression by up to 8.9-fold and 16.3-fold, respectively. Arabidopsis plants with overexpression of the GmMYB46 gene (OE) were successfully obtained, and the drought tolerance of these plants was significantly enhanced under both medium and nutrient soil cultural modes, and its growth was better than that of WT plants. Post drought stress, the electrolyte leakage of OE plants was 46.1% lower than that of WT, the contents of soluble sugar and proline were significantly higher than those of WT, increased by 54.9% and 225.0%, respectively. The activities of superoxide dismutase, peroxidase, and catalase were also significantly increased, increasing by 8.8%, 14.6% and 47.0% in root, and by 11.2%, 69.2% and 21.2% in leaf, respectively. These results indicate that the soybean transcription factor GmMYB46 enhances plant drought tolerance by increasing soluble sugar and proline content, activating antioxidant enzymes, maintaining membrane integrity, regulating osmotic pressure, scavenging reactive oxygen species, and reducing water loss. |