ER-related E2-E3 ubiquitin enzyme pair regulates ethylene response by modulating the turnover of ethylene receptors
Qingcui Zhao, Xiaofeng Zhou, Qian Chen, Ruoyun Yang, Yonghong Li, Jiaxin Zhao, Xijia Fu, Yan Lin, Yuming Liu, Liangjun Zhao, Cai‐Zhong Jiang, Susheng Gan, Qi Xie, Junping Gao, Nan Ma
Abstract
Gaseous phytohormone ethylene regulates various aspects of plant development. Ethylene is perceived by ER membrane-localized receptors, which are inactivated upon binding with ethylene molecules, thereby initiating ethylene signal transduction. Here, we report that a novel E3 ligase RING finger for Ethylene receptor Degradation (RED) and its E2 partner UBC32 ubiquitinate ethylene-bound receptors for degradation through an ER associated degradation (ERAD) pathway in both Rosa hybrida and Solanum lycopersicum. The depletion of RED or UBC32 leads to hypersensitivity to ethylene, which is manifested as premature leaf abscission and petal shedding in roses, as well as the dwarf plants and accelerated fruit ripening in tomatoes. Disruption of the conserved ethylene binding site of receptors prevents RED-mediated degradation of the receptors. Our study discovers an ERAD branch that facilitates the ethylene-induced degradation of receptors, and provides insights into how the plant’s response to ethylene can be controlled by modulating the turnover of ethylene receptors. Zhao et al. identified a novel E3 ligase RED and its E2 partner UBC32 which mediates ethylene-induced degradation of ethylene receptors ETR3 via the ERAD pathway in Rosa hybrida and Solanum lycopersicum, providing new insights into controlling ethylene response through receptor turnover.