RRC ID 81256
Author Holmes DR, Bredow M, Thor K, Pascetta SA, Sementchoukova I, Siegel KR, Zipfel C, Monaghan J.
Title A novel allele of the Arabidopsis thaliana MACPF protein CAD1 results in deregulated immune signaling.
Journal Genetics
Abstract Immune recognition in plants is governed by two major classes of receptors: pattern recognition receptors (PRRs) and nucleotide-binding leucine-rich repeat receptors (NLRs). Located at the cell surface, PRRs bind extracellular ligands originating from microbes (indicative of "non-self") or damaged plant cells (indicative of "infected-self"), and trigger signaling cascades to protect against infection. Located intracellularly, NLRs sense pathogen-induced physiological changes and trigger localized cell death and systemic resistance. Immune responses are under tight regulation in order to maintain homeostasis and promote plant health. In a forward-genetic screen to identify regulators of PRR-mediated immune signaling, we identified a novel allele of the membrane-attack complex and perforin (MACPF)-motif containing protein CONSTITUTIVE ACTIVE DEFENSE 1 (CAD1) resulting from a missense mutation in a conserved N-terminal cysteine. We show that cad1-5 mutants display deregulated immune signaling and symptoms of autoimmunity dependent on the lipase-like protein ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), suggesting that CAD1 integrity is monitored by the plant immune system. We further demonstrate that CAD1 localizes to both the cytosol and plasma membrane using confocal microscopy and subcellular fractionation. Our results offer new insights into immune homeostasis and provide tools to further decipher the intriguing role of MACPF proteins in plants.
Volume 217(4)
Published 2021-4-15
DOI 10.1093/genetics/iyab022
PII 6144930
PMID 33779749
PMC PMC8049551
MeSH Amino Acid Motifs Arabidopsis Arabidopsis Proteins / chemistry Arabidopsis Proteins / genetics* Arabidopsis Proteins / metabolism Aspartic Acid Endopeptidases / chemistry Aspartic Acid Endopeptidases / genetics* Aspartic Acid Endopeptidases / metabolism DNA-Binding Proteins / genetics DNA-Binding Proteins / metabolism Mutation, Missense Perforin / chemistry Plant Immunity* Signal Transduction*
Resource
Arabidopsis / Cultured plant cells, genes pst21828