Noncanonical Auxin Signaling

Cold Spring Harb Perspect Biol. 2021 May 3;13(5):a039917. doi: 10.1101/cshperspect.a039917.


Auxin influences all aspects of plant growth and development and exerts its function at scales ranging from the subcellular to the whole-organism level. A canonical mechanism for auxin signaling has been elucidated, which is based on derepression of downstream genes via ubiquitin-mediated degradation of transcriptional repressors. While the combinatorial nature of this canonical pathway provides great potential for specificity in the auxin response, alternative noncanonical signaling pathways required to mediate certain processes have been identified. One such pathway affects gene regulation in a manner that is reminiscent of mechanisms employed in animal hormone signaling, while another triggers transcriptional changes through auxin perception at the plasma membrane and the stabilization of transcriptional repressors. In some cases, the exact perception mechanisms and the nature of the receptors involved are yet to be revealed. In this review, we describe and discuss current knowledge on noncanonical auxin signaling and highlight unresolved questions surrounding auxin biology.

Publication types

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

MeSH terms

  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Indoleacetic Acids / metabolism*
  • Plant Development*
  • Plants / genetics
  • Plants / metabolism*
  • Protein Kinases / metabolism
  • Signal Transduction*


  • Arabidopsis Proteins
  • DNA-Binding Proteins
  • ETT protein, Arabidopsis
  • Indoleacetic Acids
  • Protein Kinases