Novel positive regulatory role for the SPL6 transcription factor in the N TIR-NB-LRR receptor-mediated plant innate immunity

PLoS Pathog. 2013 Mar;9(3):e1003235. doi: 10.1371/journal.ppat.1003235. Epub 2013 Mar 14.

Abstract

Following the recognition of pathogen-encoded effectors, plant TIR-NB-LRR immune receptors induce defense signaling by a largely unknown mechanism. We identify a novel and conserved role for the SQUAMOSA PROMOTER BINDING PROTEIN (SBP)-domain transcription factor SPL6 in enabling the activation of the defense transcriptome following its association with a nuclear-localized immune receptor. During an active immune response, the Nicotiana TIR-NB-LRR N immune receptor associates with NbSPL6 within distinct nuclear compartments. NbSPL6 is essential for the N-mediated resistance to Tobacco mosaic virus. Similarly, the presumed Arabidopsis ortholog AtSPL6 is required for the resistance mediated by the TIR-NB-LRR RPS4 against Pseudomonas syringae carrying the avrRps4 effector. Transcriptome analysis indicates that AtSPL6 positively regulates a subset of defense genes. A pathogen-activated nuclear-localized TIR-NB-LRR like N can therefore regulate defense genes through SPL6 in a mechanism analogous to the induction of MHC genes by mammalian immune receptors like CIITA and NLRC5.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Arabidopsis / immunology*
  • Arabidopsis / microbiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / immunology
  • Arabidopsis Proteins / metabolism
  • Cell Nucleus / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant*
  • Immunity, Innate
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Plant Diseases / immunology*
  • Plant Diseases / microbiology
  • Plant Immunity*
  • Plant Leaves / metabolism
  • Plant Proteins / genetics
  • Plant Proteins / immunology
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified
  • Protein Structure, Tertiary
  • Pseudomonas syringae / physiology
  • Signal Transduction
  • Tobacco / cytology
  • Tobacco / genetics
  • Tobacco / immunology*
  • Tobacco / virology
  • Tobacco Mosaic Virus / physiology
  • Transcription Factors / genetics
  • Transcription Factors / immunology
  • Transcription Factors / metabolism
  • Transcriptome

Substances

  • Arabidopsis Proteins
  • Plant Proteins
  • SPL6 protein, Arabidopsis
  • Transcription Factors