Interactions between functionally diverse fungal mutualists inconsistently affect plant performance and competition
11 páginas, 4 figuras y 3 tablas. ; Plants form mutualistic relationship with a variety of belowground fungal species. Such a mutualistic relationship can enhance plant growth and resistance to pathogens. Yet, we know little about how interactions between functionally diverse groups of fungal mutualists affect plant performance and competition. We experimentally determined the effects of interaction between two functional groups of belowground fungi that form mutualistic relationship with plants, arbuscular mycorrhizal (AM) fungi and Trichoderma, on interspecific competition between pairs of closely related plant species from four different genera. We hypothesized that the combination of two functionally diverse belowground fungal species would allow plants and fungi to partition their symbiotic relationships and relax plant–plant competition. Our results show that: 1) the AM fungal species consistently outcompeted the Trichoderma species independent of plant combinations; 2) the fungal species generally had limited effects on competitive interactions between plants; 3) however, the combination of fungal species relaxed interspecific competition in one of the four instances of plant–plant competition, despite the general competitive superiority of AM fungi over Trichoderma. We highlight that the competitive outcome between functionally diverse fungal species may show high consistency across a broad range of host plants and their combinations. However, despite this consistent competitive hierarchy, the consequences of their interaction for plant performance and competition can strongly vary among plant communities. ; MPT acknowledges funding from the German Research Foundation (DFG, TH 2307/1‐1). This project has received funding from the European Union's Horizon 2020 research and Innovation programme under grant agreement No 765290. AMM, NMvD and AB further acknowledge the COST Action FA1405. AM acknowledges funding from the program for attracting talent to Salamanca from Fundación Salamanca Ciudad de Cultura y Saberes. Further support came from the German Centre for Integrative Biodiversity Research Halle–Jena–Leipzig, funded by the German Research Foundation (FZT 118). Author contributions ‐ MPT conceived the idea. MPT, NvD, NE, CR and AM‐M developed the ideas for the experiment. VQ, MPT and AM‐M performed the experiment. MPT analyzed the data and wrote the first draft of the manuscript. All authors contributed to manuscript revisions. ; Peer reviewed