MYB30 regulates submergence tolerance by repressing ethylene biosynthesis via ACS7 in Arabidopsis.

Floods impose detrimental effects on natural and agro-ecosystems, leading to significant loss of worldwide crop production. Global climate change has even strengthened this situation. Flooding is a continuous process including two stages of submergence and re-oxygenation, and both are harmful to plant growth and development, resulting in a serious decline on crop yield. Therefore, the understanding of plant flooding tolerance and developing flooding-resistant crops are of great significance. Here, we report that the Arabidopsis thaliana (Arabidopsis) R2R3-MYB transcription factor MYB30 participates in plant submergence response through ACS7 by repressing ethylene (ET) biosynthesis. The MYB30 loss-of-function mutant exhibits reduced submergence tolerance with higher level of ET production, whereas the MYB30-overexpressing plant displays enhanced submergence tolerance and repressed ET production. The coding gene of ACC synthase 7 (ACS7) might be a direct target of MYB30 during submergence response. MYB30 binds to the promoter of ACS7 and represses its transcription. ACS7 loss-of-function mutant with defect in ET biosynthesis displays enhanced submergence tolerance, whereas plants overexpressing ACS7 exhibit a submergence-sensitive phenotype. Genetic analysis shows that ACS7 functions downstream of MYB30 both in ET biosynthesis and submergence response. Taken together, our work revealed a novel transcriptional regulation that modulates submergence response in plants.