title: An F-box gene, CPR30, functions as a negative regulator of the defense response in Arabidopsis.
abstract: 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.
authors.affiliation: State Key Laboratory of Agrobiotechnology and National Center for Plant Gene Research (Beijing), China Agricultural University, Beijing 100193, China.
authors.forename: Mingyue
authors.initials: M
authors.lastname: Gou
authors.forename: Nan
authors.initials: N
authors.lastname: Su
authors.forename: Jun
authors.initials: J
authors.lastname: Zheng
authors.forename: Junling
authors.initials: J
authors.lastname: Huai
authors.forename: Guangheng
authors.initials: G
authors.lastname: Wu
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Zhao
authors.forename: Junguang
authors.initials: J
authors.lastname: He
authors.forename: Dingzhong
authors.initials: D
authors.lastname: Tang
authors.forename: Shuhua
authors.initials: S
authors.lastname: Yang
authors.forename: Guoying
authors.initials: G
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D044783:F-Box Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000032:analysis; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D010935:Plant Diseases; D011993:Recombinant Fusion Proteins / Q000032:analysis; D044843:SKP Cullin F-Box Protein Ligases / Q000032:analysis / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism
chemical_list: C120363:ASK1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C547210:CPR30 protein, Arabidopsis; D004268:DNA-Binding Proteins; C118837:EDS1 protein, Arabidopsis; D044783:F-Box Proteins; C109369:NDR1 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D025801:Ubiquitin; D049452:Green Fluorescent Proteins; C484058:ASK2 protein, Arabidopsis; D044843:SKP Cullin F-Box Protein Ligases; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis; D020156:Salicylic Acid