He Zhao, Kai-Xuan Duan, Biao Ma, Cui-Cui Yin, Yang Hu, Jian-Jun Tao, Yi-Hua Huang, Wu-Qiang Cao, Hui Chen, Chao Yang, Zhi-Guo Zhang, Si-Jie He, Wan-Ke Zhang, Xiang-Yuan Wan, Tie-Gang Lu, Shou-Yi Chen & Jin-Song Zhang 

Nature Communications volume 11, Article number: 518 (2020)

Abstract

Ethylene plays essential roles during adaptive responses to water-saturating environments in rice, but knowledge of its signaling mechanism remains limited. Here, through an analysis of a rice ethylene-response mutant mhz1, we show that MHZ1 positively modulates root ethylene responses. MHZ1 encodes the rice histidine kinase OsHK1. MHZ1/OsHK1 is autophosphorylated at a conserved histidine residue and can transfer the phosphoryl signal to the response regulator OsRR21 via the phosphotransfer proteins OsAHP1/2. This phosphorelay pathway is required for root ethylene responses. Ethylene receptor OsERS2, via its GAF domain, physically interacts with MHZ1/OsHK1 and inhibits its kinase activity. Genetic analyses suggest that MHZ1/OsHK1 acts at the level of ethylene perception and works together with the OsEIN2-mediated pathway to regulate root growth. Our results suggest that MHZ1/OsHK1 mediates the ethylene response partially independently of OsEIN2, and is directly inhibited by ethylene receptors, thus revealing mechanistic details of ethylene signaling for root growth regulation.

Link：

1. Kai-Xuan Duan#, He Zhao#, Biao Ma#*, Cui-Cui Yin, Jian-Jun Tao, Yi-Hua Huang, Wu-Qiang Cao, Hui Chen, Chao Yang, Zhi-Guo Zhang, Si-Jie He, Wan-Ke Zhang, Xiang-Yuan Wan, Tie-Gang Lu, Shou-Yi Chen*, Jin-Song Zhang*. (2020) Histidine kinase MHZ1/OsHK1 acts immediately downstream of ethylene receptors to regulate root growth in rice. Nature Communications, 11:518, 

https://www.nature.com/articles/s41467-020-14313-0