Aberrant synthesis of indole-3-acetic acid in Saccharomyces cerevisiae triggers morphogenic transition, a virulence trait of pathogenic fungi

Genetics. 2010 May;185(1):211-20. doi: 10.1534/genetics.109.112854. Epub 2010 Mar 16.


Many plant-associated microbes synthesize the auxin indole-3-acetic acid (IAA), and several IAA biosynthetic pathways have been identified in microbes and plants. Saccharomyces cerevisiae has previously been shown to respond to IAA by inducing pseudohyphal growth. We observed that IAA also induced hyphal growth in the human pathogen Candida albicans and thus may function as a secondary metabolite signal that regulates virulence traits such as hyphal transition in pathogenic fungi. Aldehyde dehydrogenase (Ald) is required for IAA synthesis from a tryptophan (Trp) precursor in Ustilago maydis. Mutant S. cerevisiae with deletions in two ALD genes are unable to convert radiolabeled Trp to IAA, yet produce IAA in the absence of exogenous Trp and at levels higher than wild type. These data suggest that yeast may have multiple pathways for IAA synthesis, one of which is not dependent on Trp.

Publication types

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

MeSH terms

  • Candida albicans / cytology
  • Candida albicans / drug effects
  • Diploidy
  • Gene Deletion
  • Genes, Fungal / genetics
  • Genetic Testing
  • Homeostasis / drug effects
  • Humans
  • Indoleacetic Acids / chemistry
  • Indoleacetic Acids / metabolism*
  • Metabolic Networks and Pathways / drug effects
  • Morphogenesis* / drug effects
  • Quantitative Trait, Heritable*
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / pathogenicity*
  • Tryptophan / pharmacology
  • Virulence / drug effects


  • Indoleacetic Acids
  • indoleacetic acid
  • Tryptophan