title: A novel role for the TIR domain in association with pathogen-derived elicitors.
abstract: Plant innate immunity is mediated by Resistance (R) proteins, which bear a striking resemblance to animal molecules of similar function. Tobacco N is a TIR-NB-LRR R gene that confers resistance to Tobacco mosaic virus, specifically the p50 helicase domain. An intriguing question is how plant R proteins recognize the presence of pathogen-derived Avirulence (Avr) elicitor proteins. We have used biochemical cell fraction and immunoprecipitation in addition to confocal fluorescence microscopy of living tissue to examine the association between N and p50. Surprisingly, both N and p50 are cytoplasmic and nuclear proteins, and N's nuclear localization is required for its function. We also demonstrate an in planta association between N and p50. Further, we show that N's TIR domain is critical for this association, and indeed, it alone can associate with p50. Our results differ from current models for plant innate immunity that propose detection is mediated solely through the LRR domains of these molecules. The data we present support an intricate process of pathogen elicitor recognition by R proteins involving multiple subcellular compartments and the formation of multiple protein complexes.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Tessa M
authors.initials: TM
authors.lastname: Burch-Smith
authors.forename: Michael
authors.initials: M
authors.lastname: Schiff
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Caplan
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Tsao
authors.forename: Kirk
authors.initials: K
authors.lastname: Czymmek
authors.forename: Savithramma P
authors.initials: SP
authors.lastname: Dinesh-Kumar
mesh_terms: D000595:Amino Acid Sequence; D007113:Immunity, Innate; D010940:Plant Proteins / Q000502:physiology; D010944:Plants / Q000276:immunology* / Q000821:virology; D016133:Polymerase Chain Reaction; D014027:Tobacco Mosaic Virus / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D010940:Plant Proteins