COI1 is a critical component of a receptor for jasmonate and the bacterial virulence factor coronatine

Proc Natl Acad Sci U S A. 2008 May 13;105(19):7100-5. doi: 10.1073/pnas.0802332105. Epub 2008 May 5.

Abstract

Jasmonate (JA) is a lipid-derived hormone that regulates diverse aspects of plant immunity and development. An amino acid-conjugated form of JA, jasmonoyl-isoleucine (JA-Ile), stimulates binding of the F-box protein coronatine-insensitive 1 (COI1) to, and subsequent ubiquitin-dependent degradation of, jasmonate ZIM domain (JAZ) proteins that repress transcription of JA-responsive genes. The virulence factor coronatine (COR), which is produced by plant pathogenic strains of Pseudomonas syringae, suppresses host defense responses by activating JA signaling in a COI1-dependent manner. Although previous data indicate that COR acts as a molecular mimic of JA-Ile, the mechanism by which JA-Ile and COR are perceived by plant cells remains unknown. Here, we show that interaction of tomato COI1 with divergent members of the JAZ family is highly specific for JA-Ile and structurally related JA conjugates and that COR is approximately 1,000-fold more active than JA-Ile in promoting this interaction in vitro. JA-Ile competes for binding of COR to COI1-JAZ complexes, demonstrating that COR and JA-Ile are recognized by the same receptor. Binding of COR to the COI1-JAZ complex requires COI1 and is severely impaired by a point mutation in the putative ligand-binding pocket of COI1. Finally, we show that the C-terminal region of JAZ3 containing the highly conserved Jas motif is necessary and sufficient for hormone-induced COI1-JAZ interaction. These findings demonstrate that COI1 is a critical component of the JA receptor and that COR exerts its virulence effects by functioning as a potent agonist of this receptor system.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acids / chemistry
  • Amino Acids / metabolism*
  • Cyclopentanes / metabolism*
  • Indenes / chemistry
  • Indenes / metabolism*
  • Isoleucine / metabolism
  • Ligands
  • Lycopersicon esculentum / microbiology*
  • Molecular Sequence Data
  • Oxylipins / metabolism*
  • Plant Proteins / chemistry
  • Plant Proteins / metabolism*
  • Protein Binding
  • Pseudomonas syringae / pathogenicity*
  • Receptors, Cell Surface / metabolism*
  • Virulence Factors / chemistry
  • Virulence Factors / metabolism*

Substances

  • Amino Acids
  • Cyclopentanes
  • Indenes
  • Ligands
  • Oxylipins
  • Plant Proteins
  • Receptors, Cell Surface
  • Virulence Factors
  • Isoleucine
  • coronatine
  • jasmonic acid

Associated data

  • GENBANK/EU194561