Auxin-sensitive Aux/IAA proteins mediate drought tolerance in Arabidopsis by regulating glucosinolate levels

Nat Commun. 2019 Sep 6;10(1):4021. doi: 10.1038/s41467-019-12002-1.


A detailed understanding of abiotic stress tolerance in plants is essential to provide food security in the face of increasingly harsh climatic conditions. Glucosinolates (GLSs) are secondary metabolites found in the Brassicaceae that protect plants from herbivory and pathogen attack. Here we report that in Arabidopsis, aliphatic GLS levels are regulated by the auxin-sensitive Aux/IAA repressors IAA5, IAA6, and IAA19. These proteins act in a transcriptional cascade that maintains expression of GLS levels when plants are exposed to drought conditions. Loss of IAA5/6/19 results in reduced GLS levels and decreased drought tolerance. Further, we show that this phenotype is associated with a defect in stomatal regulation. Application of GLS to the iaa5,6,19 mutants restores stomatal regulation and normal drought tolerance. GLS action is dependent on the receptor kinase GHR1, suggesting that GLS may signal via reactive oxygen species. These results provide a novel connection between auxin signaling, GLS levels and drought response.

Publication types

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

MeSH terms

  • Adaptation, Physiological / genetics*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Droughts*
  • Gene Expression Profiling / methods
  • Gene Expression Regulation, Plant / drug effects
  • Glucosinolates / metabolism*
  • Indoleacetic Acids / metabolism
  • Indoleacetic Acids / pharmacology
  • Models, Genetic
  • Plant Growth Regulators / metabolism
  • Plant Growth Regulators / pharmacology
  • Plant Stomata / genetics
  • Plant Stomata / metabolism
  • Plants, Genetically Modified
  • Protein Kinases


  • Arabidopsis Proteins
  • Glucosinolates
  • Indoleacetic Acids
  • Plant Growth Regulators
  • indoleacetic acid
  • Protein Kinases
  • GHR1 protein, Arabidopsis