Habitat Disturbance Promotes Shifts in the Abundance of Major Fungal Phyla in the Roots of a Native Orchid, <i>Tipularia discolor</i>

Abstract

Orchids are a widely distributed group of flowering plants with important roles in ecosystems around the globe. However, many species are in decline due, in part, to human-driven changes in their habitat. It is well established that orchids are reliant on specific groups of mycorrhizal fungi for growth and reproduction and that these fungi can vary across the range in which an orchid species resides. Recent studies have shown that the orchid fungal mycobiome (mycobiome) includes a diverse array of non-mycorrhizal endophytic fungi that may also contribute to growth and resilience and that can vary across a particular orchid's range. The communities of mycorrhizal and non-mycorrhizal species that make up the orchid mycobiome may be altered by habitat disturbance, which could affect the ability of these plant species to thrive in different environments. Here a metagenomic approach is used to provide a snapshot of the root mycobiome of Tipularia discolor in habitats defined as disturbed or undisturbed. While amplicon sequence variant (ASV) richness and evenness were similar, the structure of the mycobiome differed between the two sites. Orchids growing in disturbed locations were associated with a greater abundance of Basidiomycota and Glomeromycota, while orchids in undisturbed habitats were associated with Ascomycota and Mucoromycota. The overall abundance of mycorrhizal families was similar across the two habitats. The data indicate that habitat disturbance induces a change in the composition of the fungal mycobiome of T. discolor, suggesting that the community of root fungi could be key to the ability of orchids to successfully adapt to different environments.