Co-option of a default secretory pathway for plant immune responses.
Kwon, Chian 1; Neu, Christina 1+; Pajonk, Simone 1; Yun, Hye Sup 1; Lipka, Ulrike 1,2+; Humphry, Matt 1; Bau, Stefan 1; Straus, Marco 1; Kwaaitaal, Mark 1; Rampelt, Heike 2; El Kasmi, Farid 3; Jurgens, Gerd 3; Parker, Jane 1; Panstruga, Ralph 1; Lipka, Volker 1,2+; Schulze-Lefert, Paul 1
[Letter]
Nature.
451(7180):835-840, February 14, 2008.
(Format: HTML, PDF)
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 1-3. 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.
(C) 2008 Nature Publishing Group