TAA1-mediated auxin biosynthesis is essential for hormone crosstalk and plant development

Cell. 2008 Apr 4;133(1):177-91. doi: 10.1016/j.cell.2008.01.047.


Plants have evolved a tremendous ability to respond to environmental changes by adapting their growth and development. The interaction between hormonal and developmental signals is a critical mechanism in the generation of this enormous plasticity. A good example is the response to the hormone ethylene that depends on tissue type, developmental stage, and environmental conditions. By characterizing the Arabidopsis wei8 mutant, we have found that a small family of genes mediates tissue-specific responses to ethylene. Biochemical studies revealed that WEI8 encodes a long-anticipated tryptophan aminotransferase, TAA1, in the essential, yet genetically uncharacterized, indole-3-pyruvic acid (IPA) branch of the auxin biosynthetic pathway. Analysis of TAA1 and its paralogues revealed a link between local auxin production, tissue-specific ethylene effects, and organ development. Thus, the IPA route of auxin production is key to generating robust auxin gradients in response to environmental and developmental cues.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / drug effects
  • Arabidopsis / embryology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Biosynthetic Pathways
  • Ethylenes / pharmacology
  • Indoleacetic Acids / metabolism*
  • Indoles / metabolism
  • Molecular Sequence Data
  • Mutation
  • Plant Roots / drug effects
  • Seedlings / metabolism
  • Sequence Alignment
  • Tryptophan Transaminase / chemistry
  • Tryptophan Transaminase / genetics
  • Tryptophan Transaminase / metabolism*


  • Ethylenes
  • Indoleacetic Acids
  • Indoles
  • indol-3-yl pyruvic acid
  • ethylene
  • Tryptophan Transaminase