Identification and cloning of a negative regulator of systemic acquired resistance, SNI1, through a screen for suppressors of npr1-1.
Systemic acquired resistance (SAR) is a plant immune response induced after a local infection by necrotizing pathogens. The Arabidopsis NPR1 gene is a positive regulator of SAR, essential for transducing the SAR signal salicylic acid (SA). Mutations in the NPR1 gene abolish the SA-induced expression of pathogenesis-related (PR) genes and resistance to pathogens. To identify additional regulators of SAR, we screened for suppressors of npr1-1. In the npr1-1 background, the sni1 (suppressor of npr1-1, inducible 1) mutant shows near wild-type levels of PR1 expression and resistance to pathogens after induction. Restoration of SAR in npr1-1 by the recessive sni1 mutation indicates that wild-type SNI1 may function as a negative regulator of SAR. We cloned the SNI1 gene and found that it encodes a leucine-rich nuclear protein.
Li
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Developmental, Cell, and Molecular Biology Group, Department of Botany, Duke University, Durham, North Carolina 27708-1000, USA.
Zhang
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Clarke
J D
JD
Li
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Y
Dong
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X
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D016153:Genes, Suppressor; D005966:Glucuronidase / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011549:Pseudomonas / Q000472:pathogenicity; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D016160:Retinoblastoma Protein / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; C105496:NPR1 protein, Arabidopsis; D009687:Nuclear Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D016160:Retinoblastoma Protein; C121026:SNI1 protein, Arabidopsis; D005966:Glucuronidase