Pine species determine fungal microbiome composition in a common garden experiment

The factors shaping the composition of microbial communities in trees remain poorly understood. We evaluated whether the core and satellite fungal communities in five pine species (Pinus radiata, Pinus pinaster, Pinus sylvestris, Pinus nigra, and Pinus uncinata) were shaped by the host species identity. Because the trees had earlier been inoculated with a fungal pathogen (Fusarium circinatum), we also explored the possibilities to detect its presence and potential co-occurrence networks. We found interspecific variation in the fungal community composition and abundance among the different tree species and the existence of a core microbiome that was independent of the host species. The presence of F. circinatum was confirmed in some samples through qPCR but the pathogen did not co-occur with a specific fungal community. The results highlight the importance of host species as a determinant of microbiome assembly in common environments