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Curr Biol. 2017 Apr 24;27(8):1148-1160. doi: 10.1016/j.cub.2017.03.018. Epub 2017 Apr 13.

Activation of a Plant NLR Complex through Heteromeric Association with an Autoimmune Risk Variant of Another NLR.

Author information

1
Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
2
Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute, University of North Carolina, Chapel Hill, NC 27599, USA.
3
Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, Carolina Center for Genome Sciences, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA.
4
Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany. Electronic address: weigel@weigelworld.org.
5
Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany. Electronic address: eunyoung.chae@tue.mpg.de.

Abstract

When independently evolved immune receptor variants meet in hybrid plants, they can activate immune signaling in the absence of non-self recognition. Such autoimmune risk alleles have recurrently evolved at the DANGEROUS MIX2 (DM2) nucleotide-binding domain and leucine-rich repeat (NLR)-encoding locus in A. thaliana. One of these activates signaling in the presence of a particular variant encoded at another NLR locus, DM1. We show that the risk variants of DM1 and DM2d NLRs signal through the same pathway that is activated when plant NLRs recognize non-self elicitors. This requires the P loops of each protein and Toll/interleukin-1 receptor (TIR)-domain-mediated heteromeric association of DM1 and DM2d. DM1 and DM2d each resides in a multimeric complex in the absence of signaling, with the DM1 complex shifting to higher molecular weight when heteromerizing DM2 variants are present. The activation of the DM1 complex appears to be sensitive to the conformation of the heteromerizing DM2 variant. Autoimmunity triggered by interaction of this NLR pair thus suggests that activity of heteromeric NLR signaling complexes depends on the sum of activation potentials of partner NLRs.

KEYWORDS:

NLR; autoimmunity; epistasis; hybrid incompatibility; plant immune receptors; resistance genes

PMID:
28416116
PMCID:
PMC5405217
DOI:
10.1016/j.cub.2017.03.018
[Indexed for MEDLINE]
Free PMC Article

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