Plant-fungal symbioses date back to when plants first colonized Earth’s landmasses 500 million years ago.
Through the Palaeozoic, CO2 concentrations declined dramatically. This was largely being driven by, and provides the backdrop for, diversification of the terrestrial flora with plants increasing in number, stature, morphological complexity and demand for inorganic carbon. Fossil and molecular evidence suggest that the earliest plants to emerge onto the land were likely similar to modern-day liverworts. As such, these tiny plants provide an excellent opportunity for us to understand how mycorrhiza-like associations in the earliest plants may have facilitated plant domination of the terrestrial biosphere. Recent findings show that the earliest plants may not have associated with mycorrhizal fungi of the Glomeromycota as has been hitherto assumed, instead fungi of the Mucoromycotina may well have been key players in plant terrestrialization.
We are only just starting to understand the diversity, structure and physiological function of the relationships between early branching lineages of land plants and their symbiotic fungi. We aim to shed new light on the role fungal symbionts may have played in the development of Earth’s ecosystems.