The focus of the Roth lab is to understand the mechanisms that underlie cross-kingdom communication during Arbuscular Mycorrhizal (AM) symbiosis.
AM symbiosis is a widespread interaction between most terrestrial plants and obligate biotrophic AM fungi. Plants benefit by receiving inorganic Phosphate (Pi) from AM fungi which it trades for organic carbon, mainly in the form of fatty acids. Fungal arbuscules are key for symbiotic exchange; these are short-lived terminally branched intracellular hyphal structures separated from the plant cytosol by a host-derived membrane, the Peri-Arbuscular Membrane (PAM).
Between the PAM and fungal cell wall is a membrane-rich Peri-Arbuscular Space (PAS) that forms an apoplastic symbiotic interface for nutrient and signal exchange. We recently discovered extracellular nanovesicles (EVs) in the PAS. In animals, EVs transport diverse cargoes (including proteins, mRNA, small interfering RNAs, lipids, and metabolites) between cells, consistent with their role in inter-cellular communication. Similarly, in plant-pathogen systems EVs transport small interfering RNAs (siRNAs) that function in cross-kingdom RNAi to modulate the interaction. The role of EVs in AM symbiosis is not known and this is a key area of research in the Roth lab.
We use cutting-edge imaging tools, molecular genetics, and biochemical approaches to identify EV cargoes and to determine their function in AM symbiosis. We also investigate the mechanisms that underlie EV biogenesis, selective cargo loading and unloading, and to determine how subpopulations of EVs modulate this dynamically regulated AM symbiosis.