title: The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance.
abstract: Plant resistance proteins of the class of nucleotide-binding and leucine-rich repeat domain proteins (NB-LRRs) are immune sensors which recognize pathogen-derived molecules termed avirulence (AVR) proteins. We show that RGA4 and RGA5, two NB-LRRs from rice, interact functionally and physically to mediate resistance to the fungal pathogen Magnaporthe oryzae and accomplish different functions in AVR recognition. RGA4 triggers an AVR-independent cell death that is repressed in the presence of RGA5 in both rice protoplasts and Nicotiana benthamiana. Upon recognition of the pathogen effector AVR-Pia by direct binding to RGA5, repression is relieved and cell death occurs. RGA4 and RGA5 form homo- and hetero-complexes and interact through their coiled-coil domains. Localization studies in rice protoplast suggest that RGA4 and RGA5 localize to the cytosol. Upon recognition of AVR-Pia, neither RGA4 nor RGA5 is re-localized to the nucleus. These results establish a model for the interaction of hetero-pairs of NB-LRRs in plants: RGA4 mediates cell death activation, while RGA5 acts as a repressor of RGA4 and as an AVR receptor.
authors.affiliation: INRA UMR BGPI, Montpellier, France CIRAD UMR BGPI, Montpellier, France CSIRO Plant Industry, Canberra, ACT, Australia.
authors.forename: Stella
authors.initials: S
authors.lastname: Césari
authors.affiliation: Iwate Biotechnology Research Center, Kitakami Iwate, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanzaki
authors.affiliation: Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama Ikoma, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: CSIRO Plant Industry, Canberra, ACT, Australia.
authors.forename: Maud
authors.initials: M
authors.lastname: Bernoux
authors.affiliation: INRA UMR BGPI, Montpellier, France CIRAD UMR BGPI, Montpellier, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Chalvon
authors.affiliation: Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama Ikoma, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kawano
authors.affiliation: Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama Ikoma, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Shimamoto
authors.affiliation: CSIRO Plant Industry, Canberra, ACT, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Dodds
authors.affiliation: Iwate Biotechnology Research Center, Kitakami Iwate, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Terauchi
authors.affiliation: INRA UMR BGPI, Montpellier, France CIRAD UMR BGPI, Montpellier, France thomas.kroj@supagro.inra.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kroj
mesh_terms: D016923:Cell Death; D060467:Disease Resistance; D020082:Magnaporthe / Q000254:growth & development* / Q000276:immunology*; D008954:Models, Biological; D012275:Oryza / Q000276:immunology* / Q000382:microbiology*; D010940:Plant Proteins / Q000276:immunology* / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D011523:Protoplasts / Q000502:physiology; D014026:Nicotiana / Q000276:immunology / Q000382:microbiology
chemical_list: D010940:Plant Proteins
keywords: Magnaporthe oryzae; pathogen recognition; plant immunity; resistance protein; rice