Auxin Response Factor2 (ARF2) and its regulated homeodomain gene HB33 mediate abscisic acid response in Arabidopsis

PLoS Genet. 2011 Jul;7(7):e1002172. doi: 10.1371/journal.pgen.1002172. Epub 2011 Jul 14.


The phytohormone abscisic acid (ABA) is an important regulator of plant development and response to environmental stresses. In this study, we identified two ABA overly sensitive mutant alleles in a gene encoding Auxin Response Factor2 (ARF2). The expression of ARF2 was induced by ABA treatment. The arf2 mutants showed enhanced ABA sensitivity in seed germination and primary root growth. In contrast, the primary root growth and seed germination of transgenic plants over-expressing ARF2 are less inhibited by ABA than that of the wild type. ARF2 negatively regulates the expression of a homeodomain gene HB33, the expression of which is reduced by ABA. Transgenic plants over-expressing HB33 are more sensitive, while transgenic plants reducing HB33 by RNAi are more resistant to ABA in the seed germination and primary root growth than the wild type. ABA treatment altered auxin distribution in the primary root tips and made the relative, but not absolute, auxin accumulation or auxin signal around quiescent centre cells and their surrounding columella stem cells to other cells stronger in arf2-101 than in the wild type. These results indicate that ARF2 and HB33 are novel regulators in the ABA signal pathway, which has crosstalk with auxin signal pathway in regulating plant growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / pharmacology*
  • Arabidopsis / drug effects*
  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Base Sequence
  • Chromatin Immunoprecipitation
  • Cyclin B / genetics
  • Cyclin B / metabolism
  • Gene Expression Regulation, Plant / drug effects
  • Genes, Plant / genetics*
  • Germination / drug effects
  • Glucuronidase / metabolism
  • Homeodomain Proteins / genetics*
  • Homeodomain Proteins / metabolism
  • Indoleacetic Acids / metabolism
  • Molecular Sequence Data
  • Mutation / genetics
  • Plant Roots / drug effects
  • Plant Roots / growth & development
  • Plants, Genetically Modified
  • Promoter Regions, Genetic / genetics
  • Protein Binding / drug effects
  • RNA Interference / drug effects
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Seeds / drug effects
  • Seeds / genetics
  • Seeds / growth & development
  • Signal Transduction / drug effects


  • ARF2 protein, Arabidopsis
  • Arabidopsis Proteins
  • CycB1 protein, Arabidopsis
  • Cyclin B
  • HB33 protein, Arabidopsis
  • Homeodomain Proteins
  • Indoleacetic Acids
  • Repressor Proteins
  • Abscisic Acid
  • Glucuronidase