Identification and cloning of a negative regulator of systemic acquired resistance, SNI1, through a screen for suppressors of npr1-1

Cell. 1999 Aug 6;98(3):329-39. doi: 10.1016/s0092-8674(00)81962-5.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Arabidopsis / genetics
  • Arabidopsis / microbiology
  • Arabidopsis / physiology*
  • Arabidopsis Proteins*
  • Base Sequence
  • Chromosome Mapping
  • Cloning, Molecular
  • DNA, Complementary
  • Gene Expression Regulation, Plant*
  • Genes, Plant
  • Genes, Suppressor
  • Glucuronidase / genetics
  • Mice
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nuclear Proteins / genetics
  • Nuclear Proteins / physiology*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified
  • Pseudomonas / pathogenicity
  • Recombinant Fusion Proteins / biosynthesis
  • Retinoblastoma Protein / chemistry
  • Retinoblastoma Protein / genetics
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Signal Transduction


  • Arabidopsis Proteins
  • DNA, Complementary
  • NPR1 protein, Arabidopsis
  • Nuclear Proteins
  • Plant Proteins
  • Recombinant Fusion Proteins
  • Retinoblastoma Protein
  • SNI1 protein, Arabidopsis
  • Glucuronidase

Associated data

  • GENBANK/AF169596