The 1R-MYB transcription factor SlMYB1L modulates drought tolerance via an ABA-dependent pathway in tomato

The MYB transcription factor family is one of the biggest transcription factors in plants, playing key roles in regulating many biological processes, including growth and development, responses to biotic and abiotic stresses and hormone signaling. In this study, we identified and characterized an 1R-MYB transcription factor, SlMYB1L, which is involved in regulating drought tolerance in tomato. SlMYB1L-RNAi transgenic plants displayed more severe dehydration phenotype with elevated malondiadehyde (MDA) and hydrogen peroxide (H2O2), as well as reduced proline content and antioxidant enzyme activities compared to wild-type under drought stress. Additionally, SlMYB1L influenced drought-induced stomatal closure and modulated endogenous ABA levels, leading to a decrease in the expression of ABA-related genes in SlMYB1L-RNAi transgenic plants. A dual-luciferase reporter assay further confirmed that SlMYB1L represses the expression of ABA catabolism gene SlCYP707A3. In conclusion, our findings suggest that SlMYB1L is a stress-responsive transcription factor that positively regulates drought tolerance and may serve as a candidate gene for developing drought-resistant crops.