Histidine kinase MHZ1/OsHK1 interacts with ethylene receptors to regulate root growth in rice

Nat Commun. 2020 Jan 24;11(1):518. doi: 10.1038/s41467-020-14313-0.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Epistasis, Genetic
  • Ethylenes / metabolism*
  • Gene Expression Regulation, Plant
  • Genes, Plant
  • Histidine Kinase / metabolism*
  • Mutation / genetics
  • Oryza / genetics
  • Oryza / growth & development*
  • Oryza / metabolism*
  • Phenotype
  • Phosphorylation
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plant Roots / metabolism*
  • Plants, Genetically Modified
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • Receptors, Cell Surface / metabolism*
  • Signal Transduction


  • Ethylenes
  • Plant Proteins
  • Receptors, Cell Surface
  • Histidine Kinase