SlRGLG2-SlBEL2 module regulates drought tolerance in tomato

BEL1-LIKE HOMEODOMAIN (BLH/BELL) family transcription factors play important roles in the response of plants to environmental stress. In this study, we found that the BLH/BELL transcription factor SlBEL2 affects drought tolerance in tomato plants, as SlBEL2-knockout (KO-SlBEL2) tomato plants showed enhanced drought tolerance, whereas SlBEL2-overexpression (OE-SlBEL2) tomato plants displayed impaired drought tolerance. Further research demonstrated that SlBEL2 negatively regulates drought tolerance in tomato plants by suppressing the expression of a number of genes that respond to drought. In addition, a RING E3 ligase, SlRGLG2, interacts with SlBEL2 and promotes ubiquitination degradation of SlBEL2, thus affecting the stability of the SlBEL2 protein, which in turn positively regulates drought tolerance in tomato plants. In summary, the SlRGLG2-SlBEL2 module regulates drought tolerance in tomato plants, and the aforementioned findings offer a novel viewpoint on the tomato plant's drought tolerance regulatory network.