Environmental context modulates rhizosphere fungal distinctiveness across plant phylogeny and functional traits.

Compositional variation in rhizosphere communities among plant species is ubiquitous and fundamental in maintaining both soil and plant biodiversity. However, the magnitude and direction of environmental effects on this variation remain unquantified in complex natural settings. Here, by integrating a large-scale field survey and a complementary glasshouse experiment with 54 plant species, we disentangled the effects of environmental variation from intrinsic plant effects on rhizosphere fungal composition. Field environments can either amplify or reduce compositional variation in rhizosphere fungal communities among co-occurring plant species compared to glasshouse conditions. Notably, within plant communities, species that were more functionally distinct tended to recruit less compositionally distinct rhizosphere fungal communities under low-soil nitrogen conditions, whereas phylogenetically distinct species recruited more compositionally distinct rhizosphere fungal communities at warmer temperatures. Our findings underscore the importance of interactions between environmental context, plant evolutionary history and functional traits in shaping plant-soil interactions.