A comprehensive structure-function analysis of Arabidopsis SNI1 defines essential regions and transcriptional repressor activity

Rebecca A. Mosher, Wendy E. Durrant, Dong Wang, Junqi Song, Xinnian Dong

Research output: Contribution to journalArticle

100 Scopus citations

Abstract

The expression of systemic acquired resistance (SAR) in plants involves the upregulation of many Pathogenesis-Related (PR) genes, which work in concert to confer resistance to a broad spectrum of pathogens. Because SAR is a costly process, SAR-associated transcription must be tightly regulated. Arabidopsis thaliana SNM (for Suppressor of NPR1, Inducible) is a negative regulator of SAR required to dampen the basal expression of PR genes. Whole genome transcriptional profiling showed that in the sni1 mutant, Nonexpresser of PR genes (NPR1)-dependent benzothiadiazole S-methylester-responsive genes were specifically derepressed. Interestingly, SNM also repressed transcription when expressed in yeast, suggesting that it functions as an active transcriptional repressor through a highly conserved mechanism. Chromatin immunoprecipitation indicated that histone modification may be involved in SNI1-mediated repression. Sequence comparison with orthologs in other plant species and a saturating NAAIRS-scanning mutagenesis of SNM identified regions in SNM that are required for its activity. The structural similarity of SNM to Armadillo repeat proteins implies that SNM may form a scaffold for interaction with proteins that modulate transcription.

Original languageEnglish (US)
Pages (from-to)1750-1765
Number of pages16
JournalPlant Cell
Volume18
Issue number7
DOIs
StatePublished - Jul 1 2006
Externally publishedYes

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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