Mutations in the AXR3 gene of Arabidopsis result in altered auxin response including ectopic expression from the SAUR-AC1 promoter

Plant J. 1996 Sep;10(3):403-13. doi: 10.1046/j.1365-313x.1996.10030403.x.


A new auxin response gene in Arabidopsis called AXR3 has been identified. This gene is defined by two semi-dominant mutations which affect many auxin-regulated developmental processes. Auxin has been shown to maintain apical dominance, inhibit root elongation, stimulate adventitious rooting, mediate root gravitropism, and stimulate transcription from the SAUR-AC1 promoter. Mutant axr3 plants show enhanced apical dominance, reduced root elongation, increased adventitious rooting, no root gravitropism, and ectopic expression from the SAUR-AC1 promoter. These phenotypes suggest an increased auxin response in the mutants. In support of this hypothesis, many of the phenotypes are partially restored to wild-type by exogenous cytokinin, a treatment that could restore a more wild-type auxin to cytokinin ratio.

MeSH terms

  • 2,4-Dichlorophenoxyacetic Acid / pharmacology
  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Amino Acids / pharmacology
  • Amino Acids, Cyclic*
  • Arabidopsis / cytology
  • Arabidopsis / drug effects
  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins*
  • Benzyl Compounds
  • Cytokinins / pharmacology
  • Gene Expression
  • Genes, Plant*
  • Indoleacetic Acids / pharmacology*
  • Kinetin
  • Mutation
  • Naphthaleneacetic Acids / pharmacology
  • Phenotype
  • Plant Proteins / genetics*
  • Promoter Regions, Genetic*
  • Purines
  • Transcription, Genetic


  • Amino Acids
  • Amino Acids, Cyclic
  • Arabidopsis Proteins
  • Benzyl Compounds
  • Cytokinins
  • Indoleacetic Acids
  • Naphthaleneacetic Acids
  • Plant Proteins
  • Purines
  • SAUR-AC1 protein, Arabidopsis
  • 2,4-Dichlorophenoxyacetic Acid
  • 1-naphthaleneacetic acid
  • 1-aminocyclopropane-1-carboxylic acid
  • indoleacetic acid
  • Adenine
  • benzylaminopurine
  • Kinetin