ECAP Directly Interacts with MYB75 for Negatively Regulating the Salt Stress-Induced Anthocyanin Biosynthesis

Salt stress-induced anthocyanin accumulation in plant play important role to defend the oxidative stress which along with the salinity. MYB75 is a major regulator to regulate the biosynthesis of anthocyanin in Arabidopsis during multiple stress environment including salt stress. However, the mechanism of MYB75 regulating anthocyanin synthesis under salt stress is not yet clear. Our study illustrated that ECAP act as a transcriptional repressor, which could directly interact with MYB75 and inhibit the transcriptional activity of MBW complex. Further study showed that salt stress released the activity of MYB75 by degrading the ECAP though 26S proteasome pathway. Furthermore, we found ECAP played a negatively role in both JA-dependent and JA-independent anthocyanin biosynthesis during the salt stress. Our research elucidates the mechanism of the ECAP-MYB75 pathway involved in the synthesis of anthocyanin induced by salt stress.