Arabidopsis growth-regulating factor7 functions as a transcriptional repressor of abscisic acid- and osmotic stress-responsive genes, including DREB2A

Plant Cell. 2012 Aug;24(8):3393-405. doi: 10.1105/tpc.112.100933. Epub 2012 Aug 31.

Abstract

Arabidopsis thaliana DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN2A (DREB2A) functions as a transcriptional activator that increases tolerance to osmotic and heat stresses; however, its expression also leads to growth retardation and reduced reproduction. To avoid these adverse effects, the expression of DREB2A is predicted to be tightly regulated. We identified a short promoter region of DREB2A that represses its expression under nonstress conditions. Yeast one-hybrid screening for interacting factors identified GROWTH-REGULATING FACTOR7 (GRF7). GRF7 bound to the DREB2A promoter and repressed its expression. In both artificial miRNA-silenced lines and a T-DNA insertion line of GRF7, DREB2A transcription was increased compared with the wild type under nonstress conditions. A previously undiscovered cis-element, GRF7-targeting cis-element (TGTCAGG), was identified as a target sequence of GRF7 in the short promoter region of DREB2A via electrophoretic mobility shift assays. Microarray analysis of GRF7 knockout plants showed that a large number of the upregulated genes in the mutant plants were also responsive to osmotic stress and/or abscisic acid. These results suggest that GRF7 functions as a repressor of a broad range of osmotic stress-responsive genes to prevent growth inhibition under normal conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / pharmacology*
  • Arabidopsis / drug effects
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Base Sequence
  • Electrophoretic Mobility Shift Assay
  • Gene Expression Regulation, Plant
  • Gene Knockout Techniques / methods
  • Genes, Plant
  • Genetic Vectors / genetics
  • Genetic Vectors / metabolism
  • Molecular Sequence Data
  • Osmosis
  • Promoter Regions, Genetic
  • Protein Binding
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Stress, Physiological*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic
  • Transcriptional Activation
  • Two-Hybrid System Techniques
  • Up-Regulation

Substances

  • Arabidopsis Proteins
  • DREB2A protein, Arabidopsis
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • Trans-Activators
  • Transcription Factors
  • Abscisic Acid