An F-box gene, CPR30, functions as a negative regulator of the defense response in Arabidopsis

Plant J. 2009 Dec;60(5):757-70. doi: 10.1111/j.1365-313X.2009.03995.x. Epub 2009 Aug 13.


Arabidopsis gain-of-resistance mutants, which show HR-like lesion formation and SAR-like constitutive defense responses, were used well as tools to unravel the plant defense mechanisms. We have identified a novel mutant, designated constitutive expresser of PR genes 30 (cpr30), that exhibited dwarf morphology, constitutive resistance to the bacterial pathogen Pseudomonas syringae and the dramatic induction of defense-response gene expression. The cpr30-conferred growth defect morphology and defense responses are dependent on ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), PHYTOALEXIN DEFICIENT 4 (PAD4), and NONRACE-SPECIFIC DISEASE RESISTANCE 1 (NDR1). Further studies demonstrated that salicylic acid (SA) could partially account for the cpr30-conferred constitutive PR1 gene expression, but not for the growth defect, and that the cpr30-conferred defense responses were NPR1 independent. We observed a widespread expression of CPR30 throughout the plant, and a localization of CPR30-GFP fusion protein in the cytoplasm and nucleus. As an F-box protein, CPR30 could interact with multiple Arabidopsis-SKP1-like (ASK) proteins in vivo. Co-localization of CPR30 and ASK1 or ASK2 was observed in Arabidopsis protoplasts. Based on these results, we conclude that CPR30, a novel negative regulator, regulates both SA-dependent and SA-independent defense signaling, most likely through the ubiquitin-proteasome pathway in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / analysis
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology*
  • Carboxylic Ester Hydrolases / genetics
  • Carboxylic Ester Hydrolases / metabolism
  • Cell Nucleus / metabolism
  • Cloning, Molecular
  • Cytoplasm / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • F-Box Proteins / analysis
  • F-Box Proteins / genetics
  • F-Box Proteins / physiology*
  • Genetic Complementation Test
  • Green Fluorescent Proteins / analysis
  • Immunity, Innate / genetics
  • Molecular Sequence Data
  • Plant Diseases
  • Recombinant Fusion Proteins / analysis
  • SKP Cullin F-Box Protein Ligases / analysis
  • SKP Cullin F-Box Protein Ligases / metabolism
  • Salicylic Acid / metabolism
  • Signal Transduction
  • Temperature
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Ubiquitin / metabolism


  • ASK1 protein, Arabidopsis
  • Arabidopsis Proteins
  • CPR30 protein, Arabidopsis
  • DNA-Binding Proteins
  • EDS1 protein, Arabidopsis
  • F-Box Proteins
  • NDR1 protein, Arabidopsis
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Ubiquitin
  • Green Fluorescent Proteins
  • ASK2 protein, Arabidopsis
  • SKP Cullin F-Box Protein Ligases
  • Carboxylic Ester Hydrolases
  • PAD4 protein, Arabidopsis
  • Salicylic Acid