Matching NLR Immune Receptors to Autoimmunity in camta3 Mutants Using Antimorphic NLR Alleles

• Published in: Cell host & microbe 2017-04, Vol.21 (4), p.518-529.e4
• Main Authors: Lolle, Signe, Greeff, Christiaan, Petersen, Klaus, Roux, Milena, Jensen, Michael Krogh, Bressendorff, Simon, Rodriguez, Eleazar, Sømark, Kenneth, Mundy, John, Petersen, Morten
• Format: Article
• Language: English
• Subjects: Alleles; Arabidopsis - immunology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Autoimmunity; Mutant Proteins - genetics; Mutant Proteins - metabolism; NLR Proteins - genetics; NLR Proteins - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 1931-3128; 1934-6069
• DOI: 10.1016/j.chom.2017.03.005

To establish infection, pathogens deploy effectors to modify or remove host proteins. Plant immune receptors with nucleotide-binding, leucine-rich repeat domains (NLRs) detect these modifications and trigger immunity. Plant NLRs thus guard host “guardees.” A corollary is that autoimmunity may result from inappropriate NLR activation because mutations in plant guardees could trigger corresponding NLR guards. To explore these hypotheses, we expressed 108 dominant-negative (DN) Arabidopsis NLRs in various lesion mimic mutants, including camta3, which exhibits autoimmunity. CAMTA3 was previously described as a negative regulator of immunity, and we find that autoimmunity in camta3 is fully suppressed by expressing DNs of two NLRs, DSC1 and DSC2. Additionally, expression of either NLR triggers cell death that can be suppressed by CAMTA3 expression. These findings support a model in which DSC1 and DSC2 guard CAMTA3, and they suggest that other negative regulators of immunity may similarly represent guardees. [Display omitted] •Dominant-negative NLR forms (DN-NLR) disrupt the function of wild-type NLR alleles•DN-NLRs can be used to screen for suppression of autoimmunity in autoimmune mutants•Two NLRs (DSC1 and DSC2) are responsible for autoimmunity in Arabidopsis camta3 mutants•Immunity triggered by DSC1 or DSC2 in tobacco is suppressed by CAMTA3 co-expression NLRs detect pathogen-induced modifications in plant proteins, triggering immunity. Lolle et al. express dominant-negative NLRs (DN-NLRs) and screen for suppressed autoimmunity in various mutants. DN-NLRs for DSC1 and DSC2 suppress autoimmunity in a camta3 mutant, a putative negative regulator of immunity, suggesting that autoimmunity results from detection of modified self.