<i>SlGSTU43</i> and <i>SlERF-B12</i> Genes Are Involved in SlMYB15-Regulated Redox Homeostasis to Enhance Cold Tolerance in Tomato

Cold stress is a major abiotic factor limiting plant growth and productivity. MYB transcription factors are important regulators of stress responses. Our previous study identified SlMYB15 as a positive regulator of cold tolerance in tomato. However, their downstream regulatory mechanisms remained unclear. Herein, subcellular localization confirmed that SlMYB15 is a nuclearly localized transcription factor. Transcriptomic analysis revealed that SlMYB15 modulates genes involved in redox processes, hormone signaling, and glutathione metabolism under cold stress. SlMYB15 upregulated <i>GSTU43</i>, <i>ERF-B12</i>, <i>CYP76A2-like</i>, and <i>CYP81D1-like</i>, reducing ROS accumulation by enhancing antioxidant enzyme activities and modulating <i>RBOH1</i>-dependent H₂O₂ signaling. Silencing <i>GSTU43</i> or <i>ERF-B12</i> impaired the cold tolerance in SlMYB15-overexpressing plants. Furthermore, SlMYB15 activated the expression of <i>GSTU43</i> and <i>ERF-B12</i> by directly binding to the promoter regions. Collectively, these findings suggest that SlMYB15 enhances cold tolerance by regulating key redox-related genes, providing new insights into MYB-mediated stress resistance in tomato.