The Arabidopsis PEPR pathway couples local and systemic plant immunity

EMBO J. 2014 Jan 7;33(1):62-75. doi: 10.1002/embj.201284303. Epub 2013 Dec 15.

Abstract

Recognition of microbial challenges leads to enhanced immunity at both the local and systemic levels. In Arabidopsis, EFR and PEPR1/PEPR2 act as the receptor for the bacterial elongation factor EF-Tu (elf18 epitope) and for the endogenous PROPEP-derived Pep epitopes, respectively. The PEPR pathway has been described to mediate defence signalling following microbial recognition. Here we show that PROPEP2/PROPEP3 induction upon pathogen challenges is robust against jasmonate, salicylate, or ethylene dysfunction. Comparative transcriptome profiling between Pep2- and elf18-treated plants points to co-activation of otherwise antagonistic jasmonate- and salicylate-mediated immune branches as a key output of PEPR signalling. Accordingly, as well as basal defences against hemibiotrophic pathogens, systemic immunity is reduced in pepr1 pepr2 plants. Remarkably, PROPEP2/PROPEP3 induction is essentially restricted to the pathogen challenge sites during pathogen-induced systemic immunity. Localized Pep application activates genetically separable jasmonate and salicylate branches in systemic leaves without significant PROPEP2/PROPEP3 induction. Our results suggest that local PEPR activation provides a critical step in connecting local to systemic immunity by reinforcing separate defence signalling pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / immunology*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Bacteria / immunology
  • Cyclopentanes / metabolism
  • Ethylenes / metabolism
  • Oxylipins / metabolism
  • Plant Immunity*
  • Protein Precursors / metabolism
  • Salicylates / metabolism
  • Signal Transduction*

Substances

  • Arabidopsis Proteins
  • Cyclopentanes
  • Ethylenes
  • Oxylipins
  • Protein Precursors
  • Salicylates
  • jasmonic acid
  • ethylene