Samuel Holland

Research Interests

My pronouns are he/they

The arbuscular mycorrhizal (AM) symbiosis is an evolutionarily ancient mutualistic symbiosis between the majority of land plants and AM fungi. The defining characteristic of AM symbiosis is the arbuscule, a highly branched fungal structure that forms within the plant symbiont's root cortical cells. The peri-arbuscular membrane, derived from the colonised plant cell, surrounds the arbuscule creating a shared interface for symbiotic communication and nutrient exchange known as the peri-arbuscular space. Arbuscules are short-lived, lasting 2-3 days on average before collapsing and withdrawing from the plant cell; both plant and fungal symbionts must coordinate symbiotic development and nutrient exchange in this short period. My research focuses on the molecular mechanisms which could underpin this communication, particularly building upon initial evidence that extracellular vesicles (EVs; small membrane-enclosed structures involved in inter-cellular communication and transport) are present in the peri-arbuscular space between plant and fungal symbionts (Roth et al. 2019). My project uses molecular genetics, bioinformatics, and biochemical approaches to functionally characterise these symbiotic EVs by identifying their protein cargos and any respective functions in AM symbiosis. In parallel, my project also uses a combination of live-cell confocal fluorescence microscopy and cryo-electron microscopy to dissect the spatiotemporal dynamics of EV secretion at this transient symbiotic interface. Combining these projects, I aim to clarify whether and how EVs regulate or modulate symbiotic engagement.

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