Ethylene regulates RGL2a homeostasis and gibberellin signaling responses by coordinating F-box protein EBF1 and kinase MPK7 in apple.

Authors

Miao-Yi Li, Lei Zhao, Di Ai, Yanru Hu, Yuepeng Han, Jian-Ping An

Published in

Plant physiology. Oct 03, 2025. Epub Oct 03, 2025.

Abstract

Although ethylene and gibberellin (GA) coordinately regulate plant growth, development, and stress responses, the specifics of how ethylene regulates GA signaling are not well understood. In this study, we clarified the molecular mechanism by which ethylene regulates GA signaling in anthocyanin biosynthesis in apple (Malus × domestica): ethylene promotes the ubiquitination and phosphorylation of a DELLA protein, a central regulator of GA signaling. Our findings revealed that ethylene and GA antagonistically regulate anthocyanin biosynthesis, with ethylene impairing the ubiquitination of the DELLA protein REPRESSOR-of-ga1-3-LIKE 2a (MdRGL2a). The F-box protein ETHYLENE-INSENSITIVE 3-BINDING F-BOX PROTEIN 1 (MdEBF1), a key regulator of ethylene signaling, destabilizes MdRGL2a via the 26S proteasome pathway. Conversely, the ethylene-activated protein kinase MITOGEN-ACTIVATED PROTEIN KINASE 7 (MdMPK7) enhances MdRGL2a stability by protecting it from MdEBF1-mediated degradation. Overall, our results demonstrate that ethylene regulates MdRGL2a homeostasis and GA signaling responses by coordinating MdEBF1 and MdMPK7. These insights advance our understanding of the post-translational modifications of DELLA proteins, GA signal transduction, and phytohormone crosstalk in anthocyanin biosynthesis.

PMID:
41042996
Bibliographic data and abstract were imported from PubMed on 04 Oct 2025.

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