Salicylic Acid Inhibits Pathogen Growth in Plants through Repression of the Auxin Signaling Pathway

Academic Article

Abstract

  • The phytohormone auxin regulates almost every aspect of plant development. At the molecular level, auxin induces gene expression through direct physical interaction with the TIR1-like F box proteins, which in turn remove the Aux/IAA family of transcriptional repressors [1-4]. A growing body of evidence indicates that many plant pathogens can either produce auxin themselves or manipulate host auxin biosynthesis to interfere with the host's normal developmental processes [5-11]. In response, plants probably evolved mechanisms to repress auxin signaling during infection as a defense strategy. Plants overaccumulating the defense signal molecule salicylic acid (SA) frequently display morphological phenotypes that are reminiscent of auxin-deficient or auxin-insensitive mutants, indicating that SA might interfere with auxin responses. By using the Affymetrix ATH1 GeneChip for Arabidopsis thaliana, we performed a comprehensive study of the effects of SA on auxin signaling [12]. We found that SA causes global repression of auxin-related genes, including the TIR1 receptor gene, resulting in stabilization of the Aux/IAA repressor proteins and inhibition of auxin responses. We demonstrate that this inhibitory effect on auxin signaling is a part of the SA-mediated disease-resistance mechanism. © 2007 Elsevier Ltd. All rights reserved.
  • Published In

  • Current Biology  Journal
  • Digital Object Identifier (doi)

    Author List

  • Wang D; Pajerowska-Mukhtar K; Culler AH; Dong X
  • Start Page

  • 1784
  • End Page

  • 1790
  • Volume

  • 17
  • Issue

  • 20