Overexpression of SlERF.F4 in Tomato Delays Fruit Ripening and Enhances Drought Tolerance

The AP2/ERF transcription factor family plays pivotal roles in regulating plant growth, development, and responses to environmental stimuli. In this study, we identified and functionally characterized SlERF.F4, a tomato (Solanum lycopersicum) ERF gene encoding a nuclear-localized protein with a conserved AP2/ERF domain. SlERF.F4 transcript levels were rapidly induced by diverse abiotic stresses and phytohormones, including drought, salinity, temperature extremes, abscisic acid (ABA), and brassinosteroids (BR). Overexpression of SlERF.F4 in tomato resulted in reduced plant height, delayed fruit ripening, and downregulation of key ripening-associated genes (RIN, CNR, E4, E8, and PG). Furthermore, SlERF.F4 transgenic lines exhibited enhanced drought tolerance, characterized by reduced wilting, lower malondialdehyde (MDA) accumulation, and significantly higher survival rates under water-deficit conditions. Collectively, these results indicate that SlERF.F4 functions as a negative regulator of fruit ripening and a positive modulator of drought tolerance, highlighting its potential as a target for tomato genetic improvement.