Hyphobox
We constructed so-called hyphoboxes separating a rhizosphere, hyphosphere, and substrate compartment, with the hyphosphere and substrate compartments accessible only to microbes but not to roots using a 50-micro m mesh. The compartments were filled with sterilized soil. The substrate compartment was additionally partly amended with 13C-15N-labeled organic substrates of different complexity (the amino acid arginine or root litter). The hyphoboxes were buried in a temperate grassland soil, allowing us to investigate the effects of the substrates on the assembly of hyphosphere microbial communities and the transfer of substrate-derived 15N via hyphosphere microbes into plant roots. Hyphoboxes and adjacent bulk soil were sampled after 8 and 20 weeks of exposure to soil and analyzed for fungal community compositions.