J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (7): 1703-1716.DOI: 10.1111/jipb.13483

• Cell and Developmental Biology • Previous Articles     Next Articles

Scaffold protein RACK1A positively regulates leaf senescence by coordinating the EIN3-miR164-ORE1 transcriptional cascade in Arabidopsis

Jan Masood, Wei Zhu†*, Yajuan Fu, Zhiyong Li, Yeling Zhou, Dong Zhang, Huihui Han, Yan Yan, Xing Wen, Hongwei Guo and Jiansheng Liang*   

  1. Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Sciences, Department of Biology, School of Life Sciences, Southern University of Science and Technology, 518055, Shenzhen, China
    These authors contributed equally to this work.
    *Correspondences: Wei Zhu (zhuwei0501@163.com); Jiansheng Liang (liangjs@sustech.edu.cn, Dr. Liang is fully responsible for the distributions of the materials associated with this article)
  • Received:2022-11-14 Accepted:2023-03-17 Online:2023-03-20 Published:2023-07-01

Abstract: Plants have adopted versatile scaffold proteins to facilitate the crosstalk between multiple signaling pathways. Leaf senescence is a well-programmed developmental stage that is coordinated by various external and internal signals. However, the functions of plant scaffold proteins in response to senescence signals are not well understood. Here, we report that the scaffold protein RACK1A (RECEPTOR FOR ACTIVATED C KINASE 1A) participates in leaf senescence mediated by ethylene signaling via the coordination of the EIN3-miR164-ORE1 transcriptional regulatory cascade. RACK1A is a novel positive regulator of ethylene-mediated leaf senescence. The rack1a mutant exhibits delayed leaf senescence, while transgenic lines overexpressing RACK1A display early leaf senescence. Moreover, RACK1A promotes EIN3 (ETHYLENE INSENSITIVE 3) protein accumulation, and directly interacts with EIN3 to enhance its DNA-binding activity. Together, they then associate with the miR164 promoter to inhibit its transcription, leading to the release of the inhibition on downstream ORE1 (ORESARA 1) transcription and the promotion of leaf senescence. This study reveals a mechanistic framework by which RACK1A promotes leaf senescence via the EIN3-miR164-ORE1 transcriptional cascade, and provides a paradigm for how scaffold proteins finely tune phytohormone signaling to control plant development.

Key words: Arabidopsis, ethylene signaling, leaf senescence, RACK1, scaffold protein, transcriptional cascade

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