title: Making sense of plant autoimmunity and 'negative regulators'.
abstract: Genetics studies the structure/function of genes via the characterization of their mutant phenotypes. In plants, a readily scorable mutant phenotype comprises macroscopic lesions symptomatic of disease in the absence of pathogens. Such mutants therefore exhibit autoimmune phenotypes. Many of these mutants are considered to be associated with immunity and the corresponding genes have been described as 'negative regulators' of immunity and/or cell death. Pathogens deliver effectors into host cells to increase infectivity by modifying or removing host proteins. Plants detect effectors via nucleotide-binding, leucine-rich repeat (NLR) immune receptors, which monitor host effector targets. In response to effector-mediated target tampering, NLR proteins potentiate immunity. The guard hypothesis proposes that NLRs 'guard' host 'guardees' targeted by pathogen effectors. An obvious corollary to this guard model is that forms of plant autoimmunity are a result of inappropriate NLR protein activation. In this review, we discuss what is known about some of the 'negative regulators' of immunity, and propose simple strategies that may help to characterize autoimmune mutants.
authors.affiliation: Department of Biology, University of Copenhagen, Denmark.
authors.forename: Eleazar
authors.initials: E
authors.lastname: Rodriguez
authors.affiliation: Department of Biology, University of Copenhagen, Denmark.
authors.forename: Hassan
authors.initials: H
authors.lastname: El Ghoul
authors.affiliation: Department of Biology, University of Copenhagen, Denmark.
authors.forename: John
authors.initials: J
authors.lastname: Mundy
authors.affiliation: Department of Biology, University of Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Petersen
mesh_terms: D015551:Autoimmunity / Q000276:immunology*; D060467:Disease Resistance / Q000276:immunology*; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate / Q000276:immunology*; D010935:Plant Diseases / Q000276:immunology*; D010940:Plant Proteins / Q000276:immunology*; D010944:Plants / Q000276:immunology*; D011971:Receptors, Immunologic; D015398:Signal Transduction; D037521:Virulence Factors
chemical_list: D010940:Plant Proteins; D011971:Receptors, Immunologic; D037521:Virulence Factors
keywords: autoimmunity; cell death; innate immunity; negative regulators; resistance proteins