Su Jiang, Ziwen Gong, Chenggang Li, Hui Tao, Feng He, Xiao Xu, Min Wang, Jisong Wang, Yuancheng Sun, Qin Feng, Zeyun Hao, Xiaoman You, Ruyi Wang, Jun Wu, Guo-Liang Wang, Yinghui Xiao, Yuese Ning, Dan Wang.E3 ubiquitin ligase-mediated degradation of Rab GTPase suppresses an MAPKK and activates immunity in rice.
Journal of Integrative Plant Biology， 2025.
http://doi.org/10.1111/jipb.70149
ABSTRACT
Small G proteins, functioning as monomeric GTPases, are critical molecular switches that regulate diverse processes in plants. However, little is known about their protein homeostasis during immune responses. Here, we demonstrate thatOsRab11C1, encoding a Rab-type GTPase, is transcriptionally upregulated uponMagnaporthe oryzaeinfection. Strikingly, loss ofOsRab11C1enhances rice blast resistance, concomitant with increased defense gene expression, MAPK activation, and ROS burst. Mechanistically, we identify the E3 ubiquitin ligase EL5 as an interactor that ubiquitinates and targets OsRab11C1 for degradation via the 26S proteasome. Consistently,EL5acts upstream ofOsRab11C1and positively regulates rice immunity. Further analysis reveals that OsRab11C1 interacts with and stabilizes mitogen-activated protein kinase kinase OsMKK6, thereby facilitating its autophosphorylation activity. In return,OsMKK6acts as a negative regulator of rice programmed cell death and immunity. Collectively, our findings unveil a dynamic EL5-OsRab11C1-OsMKK6 signaling module that orchestrates rice immunity against pathogen invasion.
Journal of Integrative Plant Biology，IF=9.3