The symbiosis between mycorrhizal fungi and terrestrial plants plays a well-known role in determining the water and nutritional status of host plants, impacting aboveground community and ecosystem dynamics. This belowground partnership has cascading effects, including enhanced plant resistance to biotic agents via changes in plant physiology and secondary chemistry with effects on higher trophic levels. Insect and pathogen population dynamics are sensitive to mycorrhizal-induce shifts in phytochemistry and these interactions can affect nutrient cycling, plant competition, and community structure and function. Furthermore, insects and pathogens, as well as shifting environmental conditions, can affect mycorrhizal abundance, thus creating ecosystem-level feedbacks. While an increasing number of studies have demonstrated the importance of mycorrhizal fungi in mediating species interactions, the nature of these relationships can which vary across environmental gradients, temporally, and with land use change. Because mycorrhizal-plant dynamics are critical components of natural and managed ecosystems, a better understanding of their role in in these ecosystems will inform ecological and evolutionary theory, ecosystem models, and land management. The goal of the proposed session is to bring together ecologists working in diverse systems to offer contemporary perspectives on the causes and consequences of variation in plant-microbe interactions. The work presented in the session spans multiple levels of biological organization and exemplifies how innovative chemical, molecular, and ecological methods can help unravel some of the complex interactions driven by mycorrhizae-induced plant responses. In the spirit of this year’s meeting theme, “Vital Connections in Ecology,” it is fitting that the topic of this symposium seeks to highlight the central role soil microbes play in connecting species at higher trophic levels, links that are critical to both species survival and ecosystem function. Participants in this session will present original work within theoretical ecological frameworks to highlight recent advances in plant-microbe interactions and the cascading effects on species interactions across time and space.