Processes underpinning the colonisation of plants by pathogenic and symbiotic filamentous microbes

Plant colonising filamentous microbes need to enter, establish a hyphal network and sustain their colonisation. Taking benefit of their broad host range, we comparatively study pathogenic Phytophthora palmivora oomycetes and symbiotic arbuscular mycorrhizal (AM) fungi within the same plant and ranging from the non-vascular liverwort Marchantia paleacea to model flowering plants and monocot crops.

I will present our most recent findings tracking filamentous microbe colonisation at the organ, tissue and cellular level using time-resolved imaging. 

Intracellular haustoria are a main site of effector secretion during Phytophthora infection. Likewise, extensively branched arbuscules are the site of nutrient exchange during AM symbiosis. We discovered changes at these intracellular interfaces in tissues colonised simultaneously by AM fungi and Phytophthora pathogens and study how Phytophthora and AM fungi both use effectors to facilitate their intracellular colonisation. Our work thus provides new insight on microbial strategies and host mechanisms underpinning the colonisation process.