Pyrosequencing reveals habitat and host effects on root-colonizing fungal communities

Belowground interactions affect communities and ecosystems, yet the diversity and composition of soil biota is still relatively unknown. We evaluated the richness, diversity, and composition of fungi colonizing three alpine plants, Taraxacum ceratophorum, T. officinale, and Polemonium viscosum. Roots were collected in open meadow and willow understory habitats above timberline. Fungal SSU rDNA was sequenced using 454 pyrosequencing, sample-specific DNA tags, and fungus-specific primers. We assigned operational taxonomic units to Glomeromycota (AM) or non-Glomeromycota (NON-AM) phyla, then tested whether habitat or host species influenced these fungal communities. AM richness was higher in the open meadow than in the willow understory, and both AM richness and diversity were highest in T. ceratophorum compared to the other host species. The NON-AM community was similar among host species except in the willow understory where diversity was reduced in T. officinale. AM composition was more similar between T. ceratophorum and P. viscosum, while NON-AM composition was more similar between T. ceratophorum and T. officinale. These results suggest that 1) alpine meadows support a more species rich AM community than nearby understory habitats, and 2) host identity affects fungal richness, diversity, and composition. This study highlights the need for more empirical tests of fungal diversity in previously unexplored ecosystems.