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.
Mesh Terms:
ATP-Binding Cassette Transporters, Arabidopsis, Arabidopsis Proteins, Ascomycota, N-Glycosyl Hydrolases, Qa-SNARE Proteins, SNARE Proteins
ATP-Binding Cassette Transporters, Arabidopsis, Arabidopsis Proteins, Ascomycota, N-Glycosyl Hydrolases, Qa-SNARE Proteins, SNARE Proteins
Nature
Date: Feb. 14, 2008
PubMed ID: 18273019
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