ARR1/12-ETP1/2 model negatively regulates submergence-induced hypoxia response in A. thaliana

Submergence-induced hypoxia stress hampers plant growth and yield, yet its molecular mechanisms remain elusive. Here, we found that ETP1/2 are repressed by submergence stress and negatively regulate plant tolerance to submergence. Further analysis showed that the repression of ETP1/2 during the submergence response is at least partly caused by the decreased expression of ARR1/12, as ARR1/12 can directly bind to the promoters via the AGATTTG motifs to activate ETP1/2 expression. ChIP-qPCR, Y1H, and EMSA further confirmed the direct interaction between ARR12 and ETP1/2. Genetic analysis demonstrated that ETP1/2 negatively regulates the submergence response downstream of ARR1/12. Additionally, some SNPs in the ARR1/12 and ETP1/2 promoters are correlated with habitat precipitation, suggesting a possible evolutionary adaptation through these SNPs. Our findings thus establish an ARR1/12-ETP1/2 module for precisely modulating the plant's hypoxic response, offering potential strategies to enhance crop resistance to submergence.