Effect of arbuscular mycorrhizal hyphae on the structure of fungal and bacterial communities: An in situ study

Soil microbial communities are key drivers of biogeochemical cycling in terrestrial ecosystems. However, under native soil conditions, since plant roots intimately interact with arbuscular mycorrhizal fungus (AMF) hyphae, the individual effects of AMF hyphae on the diversity and abundance of soil microbial communities remain unclear. Using an ingrowth core design, we isolated the hyphae of AMF from roots and quantified the affected soil microbial communities using meta-barcoding sequencing techniques. The results revealed that the presence of AMF hyphae significantly increased the diversity of fungi but not that of bacteria. In addition, AMF hyphae influenced the relative abundance of certain microbial taxa: the abundance of the phylum Ascomycota significantly increased, whereas that of the species Mortierella horticola and the phylum Mortierellomycota significantly decreased. The redundancy analysis results revealed that the soil nutrient availability and soil pH were closely related to the microbial community. In conclusion, AMF hyphae affect the structure of fungal and bacterial communities, and this process is regulated by soil properties. These findings provide new insight into the small-scale but complex interactions between the hyphae of AMF and microbes in terrestrial ecosystem soils from an in situ perspective.