title: Rice Exo70 interacts with a fungal effector, AVR-Pii, and is required for AVR-Pii-triggered immunity.
abstract: Vesicle trafficking including the exocytosis pathway is intimately associated with host immunity against pathogens. However, we still have insufficient knowledge about how it contributes to immunity, and how pathogen factors affect it. In this study, we explore host factors that interact with the Magnaporthe oryzae effector AVR-Pii. Gel filtration chromatography and co-immunoprecipitation assays identified a 150 kDa complex of proteins in the soluble fraction comprising AVR-Pii and OsExo70-F2 and OsExo70-F3, two rice Exo70 proteins presumably involved in exocytosis. Simultaneous knockdown of OsExo70-F2 and F3 totally abrogated Pii immune receptor-dependent resistance, but had no effect on Pia- and Pik-dependent resistance. Knockdown levels of OsExo70-F3 but not OsExo70-F2 correlated with reduction of Pii function, suggesting that OsExo70-F3 is specifically involved in Pii-dependent resistance. Under our current experimental conditions, over-expression of AVR-Pii or knockdown of OsExo70-F2 and -F3 genes in rice did not affect the virulence of compatible isolates of M. oryzae. AVR-Pii interaction with OsExo70-F3 appears to play a crucial role in immunity triggered by Pii, suggesting a role for OsExo70 as a decoy or helper in Pii/AVR-Pii interactions.
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Fujisaki
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Abe
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Ito
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Saitoh
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanzaki
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Eiko
authors.initials: E
authors.lastname: Kanzaki
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Hiroe
authors.initials: H
authors.lastname: Utsushi
authors.affiliation: Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: The Sainsbury Laboratory, Norwich Research Park, Norwich, UK.
authors.forename: Sophien
authors.initials: S
authors.lastname: Kamoun
authors.affiliation: Iwate Biotechnology Research Center, Kitakami, Iwate, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Terauchi
mesh_terms: D000595:Amino Acid Sequence; D019117:Burkholderia / Q000472:pathogenicity; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D054884:Host-Pathogen Interactions; D020082:Magnaporthe / Q000378:metabolism / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D012275:Oryza / Q000276:immunology* / Q000382:microbiology* / Q000502:physiology; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D055503:Protein Multimerization; D014974:Xanthomonas / Q000472:pathogenicity
chemical_list: D005656:Fungal Proteins; D010940:Plant Proteins
keywords: AVR-Pii; Exo70; avirulence effector; decoy; effector-triggered immunity; helper