Most plants on Earth form a symbiosis with mycorrhizal fungi. This vital connection between plants and fungi stretches back over 400 million years, and continues to shape plant species interactions and ecosystem processes. In many ways, the mycorrhizal symbiosis has become a model for understanding how microbial life shapes the macro-biological world. In this session mycorrhizal ecologists will present research that is truly pushing the boundaries of our understanding of mycorrhizal symbiosis, and its consequences for plant and fungal biogeography and ecosystem function. Several scientists are taking advantage of new molecular approaches to shed light on previously untestable hypotheses. Others are making new connections across scales, highlighting how molecular interactions among plants and mycorrhizal fungi have ecosystem consequences that ripple out across the landscape. By bringing these diverse approaches together, we hope to inspire our audience to draw new connections between plants, fungi and the Earth.