The MKK3-MPK7 cascade phosphorylates ERF4 and promotes its rapid degradation for releasing seed dormancy in Arabidopsis

• Published in: Molecular plant
• Main Authors: Chen, Xi, Li, Qiujia, Ding, Ling, Zhang, Shengnan, Shan, Siyao, Xiong, Xiong, Jiang, Wenhui, Zhao, Bo, Zhang, Liying, Luo, Ying, Lian, Yiming, Kong, Xiuqin, Ding, Xiali, Zhang, Jun, Li, Chunli, Soppe, Wim J J, Xiang, Yong
• Format: Journal Article
• Language: English
• Published: 13.09.2023
• ISSN: 1752-9867; 1752-9867
• DOI: 10.1016/j.molp.2023.09.006

Seeds establish dormancy to delay germination until the arrival of a favorable growth season. Here, we identify a fate switch constituted by the MKK3-MPK7 kinase cascade and the ethylene response factor ERF4 responsible for the seed state transition from dormancy to germination. We show that dormancy-breaking factors activate the MKK3-MPK7 module, which affects and relies on the expression of some EXPAs to control seed dormancy. Furthermore, we identify a direct downstream substrate of this module, ERF4, which suppresses the expression of these EXPAs by directly binding to the GCC boxes in their exon regions. The activated MKK3-MPK7 module phosphorylates ERF4, leading to its rapid degradation, thereby releasing its inhibitory effect on the expression of these EXPAs. Overall, our work identifies a signaling chain consisting of protein phosphorylation, degradation, and gene transcription, dependent on which the germination promoters within the embryo are sensing and activated by the germination signals from ambient conditions.Seeds establish dormancy to delay germination until the arrival of a favorable growth season. Here, we identify a fate switch constituted by the MKK3-MPK7 kinase cascade and the ethylene response factor ERF4 responsible for the seed state transition from dormancy to germination. We show that dormancy-breaking factors activate the MKK3-MPK7 module, which affects and relies on the expression of some EXPAs to control seed dormancy. Furthermore, we identify a direct downstream substrate of this module, ERF4, which suppresses the expression of these EXPAs by directly binding to the GCC boxes in their exon regions. The activated MKK3-MPK7 module phosphorylates ERF4, leading to its rapid degradation, thereby releasing its inhibitory effect on the expression of these EXPAs. Overall, our work identifies a signaling chain consisting of protein phosphorylation, degradation, and gene transcription, dependent on which the germination promoters within the embryo are sensing and activated by the germination signals from ambient conditions.