Co-option of a default secretory pathway for plant immune responses.
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.
Kwon
Chian
C
Department of Plant Microbe Interactions, Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany.
Neu
Christina
C
Pajonk
Simone
S
Yun
Hye Sup
HS
Lipka
Ulrike
U
Humphry
Matt
M
Bau
Stefan
S
Straus
Marco
M
Kwaaitaal
Mark
M
Rampelt
Heike
H
El Kasmi
Farid
F
Jürgens
Gerd
G
Parker
Jane
J
Panstruga
Ralph
R
Lipka
Volker
V
Schulze-Lefert
Paul
P
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
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