An F-box gene, CPR30, functions as a negative regulator of the defense response in Arabidopsis.
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.
Mesh Terms:
Amino Acid Sequence, Arabidopsis, Arabidopsis Proteins, Carboxylic Ester Hydrolases, Cell Nucleus, Cloning, Molecular, Cytoplasm, DNA-Binding Proteins, F-Box Proteins, Genetic Complementation Test, Green Fluorescent Proteins, Immunity, Innate, Molecular Sequence Data, Plant Diseases, Recombinant Fusion Proteins, SKP Cullin F-Box Protein Ligases, Salicylic Acid, Signal Transduction, Temperature, Transcription Factors, Ubiquitin
Amino Acid Sequence, Arabidopsis, Arabidopsis Proteins, Carboxylic Ester Hydrolases, Cell Nucleus, Cloning, Molecular, Cytoplasm, DNA-Binding Proteins, F-Box Proteins, Genetic Complementation Test, Green Fluorescent Proteins, Immunity, Innate, Molecular Sequence Data, Plant Diseases, Recombinant Fusion Proteins, SKP Cullin F-Box Protein Ligases, Salicylic Acid, Signal Transduction, Temperature, Transcription Factors, Ubiquitin
Plant J.
Date: Dec. 01, 2009
PubMed ID: 19682297
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