Abstrakt av seminarium (på engelska): In forest ecosystems, tree roots are typically colonized by a range ectomycorrhizal fungi that are thought to supply a range of nutrients in return for plant photosynthate. Despite the prevalence of these important fungi, little is understood concerning the molecular underpinnings of these relationships and where the balance of power in the relationship actually lies. In our co-presented seminar we will split this question into two parts: what is the role of inter-kingdom communication between host and fungal cells to favor the formation of these symbioses and is parity in the exchange of nutrients between the two symbiotic partners required for colonization maintenance and success. Using examples from our high- and medium-throughput screening using the fungus Pisolithus microcarpus and its host Eucalyptus grandis (e.g. sequencing, metabolomics, protein activity analysis), Jonathan will discuss the steps forward we have made in recent years in understanding the evolution and role of both protein- and metabolomic-based dialogue between mutualistic fungi and their hosts. Using stable isotope tracing and transcriptomic analyses, Krista will talk about mechanisms of how nutrient availability and competition in between the two organisms for nutrients affects these interactions. Further, she will talk about mechanisms used by the plant to protect its own interests from unhelpful symbionts, and how these mechanisms affect the exchange of nutrients between the two symbiotic partners.Together, we would like to reflect upon some of the bigger-picture ramifications of these findings and highlight some avenues of research that may be attractive to pursue in the future.