Abstract

Extracellular vesicles (EVs) transport biologically active molecules and are known to mediate host defence against microbial pathogens, including plant fungal pathogens. However, the mechanism by which pathogens disrupt EV-dependent defence remains unclear. Here we show that Phytophthora capsici , a global crop pathogen, counteracts EV-mediated plant defence through targeted lipase activity. We show that Arabidopsis releases EVs containing tetraspanin (TET), specifically TET8- and TET9-EVs, which damage germinated spores of Phytophthora , reducing infection. As a counter-defence, Phytophthora secretes an infection-induced apoplastic lipase, Plant Extracellular Vesicle Destroyer 1 (PED1), which targets TET8- and TET9-EVs. This occurs via interaction with the EV membrane-localized protein Defective Glycosylation 1 (DGL1), which directly interacts and co-localizes with TET8 and TET9 on the EV membrane. PED1 damages TET8- and TET9-EVs through its lipase activity towards campesteryl esters, suppressing EV-mediated plant defence. Our study reveals a mechanism used by Phytophthora to counteract EV-mediated host defence.