Phytohormone Collaboration: Zooming in on Auxin-Brassinosteroid Interactions

Trends Cell Biol. 2007 Oct;17(10):485-92. doi: 10.1016/j.tcb.2007.08.003. Epub 2007 Sep 29.


Similar to animal hormones, classic plant hormones are small organic molecules that regulate physiological and developmental processes. In development, this often involves the regulation of growth through the control of cell size or division. The plant hormones auxin and brassinosteroid modulate both cell expansion and proliferation and are known for their overlapping activities in physiological assays. Recent molecular genetic analyses in the model plant Arabidopsis suggest that this reflects interdependent and often synergistic action of the two hormone pathways. Such pathway interactions probably occur through the combinatorial regulation of common target genes by auxin- and brassinosteroid-controlled transcription factors. Moreover, auxin and brassinosteroid signaling and biosynthesis and auxin transport might be linked by an emerging upstream connection involving calcium-calmodulin and phosphoinositide signaling.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Calcium Signaling
  • Calmodulin / metabolism
  • Cell Enlargement
  • Cell Proliferation
  • Feedback, Physiological
  • Gene Expression Regulation, Plant
  • Indoleacetic Acids / metabolism*
  • Phosphatidylinositols / metabolism
  • Plant Growth Regulators / metabolism*
  • Receptors, G-Protein-Coupled / metabolism
  • Signal Transduction*
  • Steroids, Heterocyclic / metabolism*
  • Transcription Factors / metabolism
  • Transcription, Genetic


  • Arabidopsis Proteins
  • Calmodulin
  • Indoleacetic Acids
  • Phosphatidylinositols
  • Plant Growth Regulators
  • Receptors, G-Protein-Coupled
  • Steroids, Heterocyclic
  • Transcription Factors