Receptor-like cytoplasmic kinases integrate signaling from multiple plant immune receptors and are targeted by a Pseudomonas syringae effector

Cell Host Microbe. 2010 Apr 22;7(4):290-301. doi: 10.1016/j.chom.2010.03.007.


Cell-surface-localized plant immune receptors, such as FLS2, detect pathogen-associated molecular patterns (PAMPs) and initiate PAMP-triggered immunity (PTI) through poorly understood signal-transduction pathways. The pathogenic Pseudomonas syringae effector AvrPphB, a cysteine protease, cleaves the Arabidopsis receptor-like cytoplasmic kinase PBS1 to trigger cytoplasmic immune receptor RPS5-specified effector-triggered immunity (ETI). Analyzing the function of AvrPphB in plants lacking RPS5, we find that AvrPphB can inhibit PTI by cleaving additional PBS1-like (PBL) kinases, including BIK1, PBL1, and PBL2. In unstimulated plants, BIK1 and PBL1 interact with FLS2 and are rapidly phosphorylated upon FLS2 activation by its ligand flg22. Genetic and molecular analyses indicate that BIK1, and possibly PBL1, PBL2, and PBS1, integrate immune signaling from multiple immune receptors. Whereas AvrPphB-mediated degradation of one of these kinases, PBS1, is monitored by RPS5 to initiate ETI, this pathogenic effector targets other PBL kinases for PTI inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / immunology*
  • Arabidopsis / microbiology*
  • Arabidopsis Proteins / metabolism*
  • Bacterial Proteins / metabolism*
  • Phosphorylation
  • Plant Proteins / metabolism*
  • Protein Binding
  • Protein Kinases / metabolism
  • Protein Serine-Threonine Kinases / metabolism*
  • Pseudomonas syringae / pathogenicity*
  • Signal Transduction
  • Virulence Factors / metabolism*


  • Arabidopsis Proteins
  • Bacterial Proteins
  • Plant Proteins
  • RPS5 protein, Arabidopsis
  • Virulence Factors
  • avrPphB protein, Pseudomonas syringae
  • Protein Kinases
  • FLS2 protein, Arabidopsis
  • PBS1 protein, Arabidopsis
  • BIK1 protein, Arabidopsis
  • Protein Serine-Threonine Kinases