H2O2 sulfenylates GRF8 to facilitate JA response by relieving MYC2 inhibition in Arabidopsis

H2O2 functions as a signaling molecule regulating plant growth, development and stress responses, however its role in jasmonic acid (JA) signaling transduction and JA-regulated biological processes remains elusive. Here, we report that the 14-3-3 protein GRF8 is a critical factor inhibiting JA signaling while H2O2 removes this inhibition to facilitate JA response during root growth and leaf senescence in Arabidopsis. GRF8 interacts with and inhibits MYC2, the master transcription factor in JA signaling. It recruits JAZ repressors to enhance their interaction with and inhibition of MYC2. Additionally, GRF8 competes with MED25, a subunit of the Mediator coactivator complex, for interaction with MYC2. Upon increased JA levels, H2O2 sulfenylates GRF8 at Cysteine-103, reducing its interaction with MYC2 and releasing MYC2 activity to stimulate the JA response. Collectively, our findings demonstrate that H2O2, as a signaling molecule, sulfenylates GRF8 to alleviate MYC2 inhibition, thereby facilitating the JA response in Arabidopsis.