Bifurcation of Arabidopsis NLR immune signaling via Ca²⁺-dependent protein kinases

PLoS Pathog. 2013 Jan;9(1):e1003127. doi: 10.1371/journal.ppat.1003127. Epub 2013 Jan 31.

Abstract

Nucleotide-binding domain leucine-rich repeat (NLR) protein complexes sense infections and trigger robust immune responses in plants and humans. Activation of plant NLR resistance (R) proteins by pathogen effectors launches convergent immune responses, including programmed cell death (PCD), reactive oxygen species (ROS) production and transcriptional reprogramming with elusive mechanisms. Functional genomic and biochemical genetic screens identified six closely related Arabidopsis Ca²⁺-dependent protein kinases (CPKs) in mediating bifurcate immune responses activated by NLR proteins, RPS2 and RPM1. The dynamics of differential CPK1/2 activation by pathogen effectors controls the onset of cell death. Sustained CPK4/5/6/11 activation directly phosphorylates a specific subgroup of WRKY transcription factors, WRKY8/28/48, to synergistically regulate transcriptional reprogramming crucial for NLR-dependent restriction of pathogen growth, whereas CPK1/2/4/11 phosphorylate plasma membrane-resident NADPH oxidases for ROS production. Our studies delineate bifurcation of complex signaling mechanisms downstream of NLR immune sensors mediated by the myriad action of CPKs with distinct substrate specificity and subcellular dynamics.

Publication types

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

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / immunology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / immunology
  • Cell Death
  • Disease Resistance / physiology*
  • Focal Adhesion Kinase 2 / genetics
  • Focal Adhesion Kinase 2 / immunology*
  • Gene Expression Regulation, Plant
  • Intracellular Signaling Peptides and Proteins
  • Signal Transduction*
  • Substrate Specificity

Substances

  • Arabidopsis Proteins
  • Intracellular Signaling Peptides and Proteins
  • Focal Adhesion Kinase 2