The synthetic elicitor 3,5-dichloroanthranilic acid induces NPR1-dependent and NPR1-independent mechanisms of disease resistance in Arabidopsis

Plant Physiol. 2009 May;150(1):333-47. doi: 10.1104/pp.108.133678. Epub 2009 Mar 20.


Immune responses of Arabidopsis (Arabidopsis thaliana) are at least partially mediated by coordinated transcriptional up-regulation of plant defense genes, such as the Late/sustained Up-regulation in Response to Hyaloperonospora parasitica (LURP) cluster. We found a defined region in the promoter of the LURP member CaBP22 to be important for this response. Using a CaBP22 promoter-reporter fusion, we have established a robust and specific high-throughput screening system for synthetic defense elicitors that can be used to trigger defined subsets of plant immune responses. Screening a collection of 42,000 diversity-oriented molecules, we identified 114 candidate LURP inducers. One representative, 3,5-dichloroanthranilic acid (DCA), efficiently induced defense reactions to the phytopathogens H. parasitica and Pseudomonas syringae. In contrast to known salicylic acid analogs, such as 2,6-dichloroisonicotinic acid (INA), which exhibit a long-lasting defense-inducing activity and are fully dependent on the transcriptional cofactor NPR1 (for Nonexpresser of Pathogenesis-Related genes1), DCA acts transiently and is only partially dependent on NPR1. Microarray analyses revealed a cluster of 142 DCA- and INA-responsive genes that show a pattern of differential expression coinciding with the kinetics of DCA-mediated disease resistance. These ACID genes (for Associated with Chemically Induced Defense) constitute a core gene set associated with chemically induced disease resistance, many of which appear to encode components of the natural immune system of Arabidopsis.

Publication types

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

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / microbiology
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / physiology*
  • Calmodulin / chemistry
  • Calmodulin / genetics
  • Calmodulin / physiology*
  • Chlorobenzoates
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant / drug effects*
  • Genes, Reporter
  • Immunity, Innate / genetics
  • Kinetics
  • Multigene Family
  • Oligonucleotide Array Sequence Analysis
  • Oomycetes / growth & development
  • Promoter Regions, Genetic
  • Pseudomonas syringae / growth & development
  • Recombinant Fusion Proteins / analysis
  • Salicylic Acid / pharmacology
  • ortho-Aminobenzoates / chemistry
  • ortho-Aminobenzoates / pharmacology*


  • 3,5-dichloroanthranilic acid
  • Arabidopsis Proteins
  • CaBP22 protein, Arabidopsis
  • Calmodulin
  • Chlorobenzoates
  • NPR1 protein, Arabidopsis
  • Recombinant Fusion Proteins
  • ortho-Aminobenzoates
  • Salicylic Acid