MYBL2 enhances salt tolerance via BES1-MYBL2-TPR3 module-mediated transcriptional repression

As a major abiotic stress factor, soil salinity severely impacts plant viability. Plant evolved multiple transcriptional machineries through an intricate network of transcription factors to maintain the growth and stress response. Here, we report that MYB-related transcription factor MYBL2 positively regulates salt tolerance in Arabidopsis thaliana. We found mybl2 mutants were more sensitive to salt stress, while MYBL2 overexpressing resulted in plants with increased antioxidant defence and tolerance to salinity stress. Moreover, MYBL2 physically interacts with the TPR3 corepressor via TLLLFR located at the C-terminal end. Further analyses revealed repression of HAT1 and NAC032 by MYBL2 is dependent on functional BES1 and TPR3. MYBL2 regulates repression of HAT1 and NAC032 via BES1-MYBL2-TPR3 module, thereby leading to increase salt-responsive gene transcription and suppress salt-induced senescence gene expression, thus conferring plant salt tolerance. Collectively, our results illustrate that transcriptional repression mechanism mediated by BES1-MYBL2-TPR3 module through regulating of downstream genes expression and help reveal the function of transcription repressors in modulating of plant stress response.