Selective regulation of the chitin-induced defense response by the Arabidopsis receptor-like cytoplasmic kinase PBL27

Plant J. 2014 Jul;79(1):56-66. doi: 10.1111/tpj.12535. Epub 2014 May 23.


Recognition of microbe-associated molecular patterns (MAMPs) initiates pattern-triggered immunity in host plants. Pattern recognition receptors (PRRs) and receptor-like cytoplasmic kinases (RLCKs) are the major components required for sensing and transduction of these molecular patterns. However, the regulation of RLCKs by PRRs and their specificity remain obscure. In this study we show that PBL27, an Arabidopsis ortholog of OsRLCK185, is an immediate downstream component of the chitin receptor CERK1 and contributes to the regulation of chitin-induced immunity in Arabidopsis. Knockout of PBL27 resulted in the suppression of several chitin-induced defense responses, including the activation of MPK3/6 and callose deposition as well as in disease resistance against fungal and bacterial infections. On the other hand, the contribution of PBL27 to flg22 signaling appears to be very limited, suggesting that PBL27 selectively regulates defense signaling downstream of specific PRR complexes. In vitro phosphorylation experiments showed that CERK1 preferentially phosphorylated PBL27 in comparison to BIK1, whereas phosphorylation of PBL27 by BAK1 was very low compared with that of BIK1. Thus, the substrate specificity of the signaling receptor-like kinases, CERK1 and BAK1, may determine the preference of downstream RLCKs.

Keywords: Arabidopsis thaliana; CERK1; PBL27; chitin; microbe-associated molecular pattern; plant immunity; receptor; receptor-like cytoplasmic kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternaria / physiology
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis / immunology
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Cell Membrane / metabolism
  • Chitin / metabolism
  • Disease Resistance*
  • Gene Expression Regulation, Plant*
  • Gene Knockout Techniques
  • Glucans / metabolism
  • Models, Biological
  • Phosphorylation
  • Plant Diseases / immunology*
  • Plant Leaves / enzymology
  • Plant Leaves / genetics
  • Plant Leaves / immunology
  • Plant Leaves / physiology
  • Plants, Genetically Modified
  • Protein Kinases / genetics
  • Protein Kinases / metabolism
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Reactive Oxygen Species / metabolism
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Receptors, Pattern Recognition
  • Signal Transduction*
  • Substrate Specificity
  • Tobacco / enzymology
  • Tobacco / genetics
  • Tobacco / immunology
  • Tobacco / physiology


  • Arabidopsis Proteins
  • Glucans
  • Reactive Oxygen Species
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Pattern Recognition
  • Chitin
  • callose
  • PBL27 protein, Arabidopsis
  • Protein Kinases
  • BAK1 protein, Arabidopsis
  • CERK1 protein, Arabidopsis
  • Protein Serine-Threonine Kinases