title: Two distinct secretion systems facilitate tissue invasion by the rice blast fungus Magnaporthe oryzae.
abstract: To cause plant diseases, pathogenic micro-organisms secrete effector proteins into host tissue to suppress immunity and support pathogen growth. Bacterial pathogens have evolved several distinct secretion systems to target effector proteins, but whether fungi, which cause the major diseases of most crop species, also require different secretory mechanisms is not known. Here we report that the rice blast fungus Magnaporthe oryzae possesses two distinct secretion systems to target effectors during plant infection. Cytoplasmic effectors, which are delivered into host cells, preferentially accumulate in the biotrophic interfacial complex, a novel plant membrane-rich structure associated with invasive hyphae. We show that the biotrophic interfacial complex is associated with a novel form of secretion involving exocyst components and the Sso1 t-SNARE. By contrast, effectors that are secreted from invasive hyphae into the extracellular compartment follow the conventional secretory pathway. We conclude that the blast fungus has evolved distinct secretion systems to facilitate tissue invasion.
authors.affiliation: Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: Martha C
authors.initials: MC
authors.lastname: Giraldo
authors.forename: Yasin F
authors.initials: YF
authors.lastname: Dagdas
authors.forename: Yogesh K
authors.initials: YK
authors.lastname: Gupta
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Mentlak
authors.forename: Mihwa
authors.initials: M
authors.lastname: Yi
authors.forename: Ana Lilia
authors.initials: AL
authors.lastname: Martinez-Rocha
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Saitoh
authors.forename: Ryohei
authors.initials: R
authors.lastname: Terauchi
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Talbot
authors.forename: Barbara
authors.initials: B
authors.lastname: Valent
mesh_terms: D020126:Brefeldin A / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D025301:Hyphae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020082:Magnaporthe / Q000166:cytology / Q000187:drug effects / Q000472:pathogenicity*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D050600:SNARE Proteins / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D050600:SNARE Proteins; D020126:Brefeldin A