Rerouting of plant late endocytic trafficking toward a pathogen interface.

A number of plant pathogenic and symbiotic microbes produce specialized cellular structures that invade host cells where they remain enveloped by host-derived membranes. The mechanisms underlying the biogenesis and functions of host-microbe interfaces are poorly understood. Here, we show that plant late endocytic trafficking is diverted toward the extrahaustorial membrane (EHM); a host-pathogen interface that develops in plant cells invaded by Irish potato famine pathogen Phytophthora infestans. A late endosome and tonoplast marker protein Rab7 GTPase RabG3c, but not a tonoplast-localized sucrose transporter, is recruited to the EHM, suggesting specific rerouting of vacuole-targeted late endosomes to a host-pathogen interface. We revealed the dynamic nature of this process by showing that, upon activation, a cell surface immune receptor traffics toward the haustorial interface. Our work provides insight into the biogenesis of the EHM and reveals dynamic processes that recruit membrane compartments and immune receptors to this host-pathogen interface.