title: Co-option of a default secretory pathway for plant immune responses.
abstract: Cell-autonomous immunity is widespread in plant-fungus interactions and terminates fungal pathogenesis either at the cell surface or after pathogen entry. Although post-invasive resistance responses typically coincide with a self-contained cell death of plant cells undergoing attack by parasites, these cells survive pre-invasive defence. Mutational analysis in Arabidopsis identified PEN1 syntaxin as one component of two pre-invasive resistance pathways against ascomycete powdery mildew fungi. Here we show that plasma-membrane-resident PEN1 promiscuously forms SDS-resistant soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) complexes together with the SNAP33 adaptor and a subset of vesicle-associated membrane proteins (VAMPs). PEN1-dependent disease resistance acts in vivo mainly through two functionally redundant VAMP72 subfamily members, VAMP721 and VAMP722. Unexpectedly, the same two VAMP proteins also operate redundantly in a default secretory pathway, suggesting dual functions in separate biological processes owing to evolutionary co-option of the default pathway for plant immunity. The disease resistance function of the secretory PEN1-SNAP33-VAMP721/722 complex and the pathogen-induced subcellular dynamics of its components are mechanistically reminiscent of immunological synapse formation in vertebrates, enabling execution of immune responses through focal secretion.
authors.affiliation: Department of Plant Microbe Interactions, Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany.
authors.forename: Chian
authors.initials: C
authors.lastname: Kwon
authors.forename: Christina
authors.initials: C
authors.lastname: Neu
authors.forename: Simone
authors.initials: S
authors.lastname: Pajonk
authors.forename: Hye Sup
authors.initials: HS
authors.lastname: Yun
authors.forename: Ulrike
authors.initials: U
authors.lastname: Lipka
authors.forename: Matt
authors.initials: M
authors.lastname: Humphry
authors.forename: Stefan
authors.initials: S
authors.lastname: Bau
authors.forename: Marco
authors.initials: M
authors.lastname: Straus
authors.forename: Mark
authors.initials: M
authors.lastname: Kwaaitaal
authors.forename: Heike
authors.initials: H
authors.lastname: Rampelt
authors.forename: Farid
authors.initials: F
authors.lastname: El Kasmi
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Jane
authors.initials: J
authors.lastname: Parker
authors.forename: Ralph
authors.initials: R
authors.lastname: Panstruga
authors.forename: Volker
authors.initials: V
authors.lastname: Lipka
authors.forename: Paul
authors.initials: P
authors.lastname: Schulze-Lefert
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001203:Ascomycota / Q000502:physiology; D009699:N-Glycosyl Hydrolases / Q000235:genetics / Q000378:metabolism; D050765:Qa-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D050600:SNARE Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; C510424:PDR8 protein, Arabidopsis; C479425:PEN1 protein, Arabidopsis; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D009699:N-Glycosyl Hydrolases; C505663:PEN2 protein, Arabidopsis