Effects of mineral substrate on ectomycorrhizal fungal colonization and bacterial community structure

Ectomycorrhizal (ECM) fungi can promote the nutrient uptake of plants from soil minerals by bioweathering. However, effects of different minerals on ECM fungal colonization and bacterial community structures in the soil remains poorly documented. Here, we investigated ECM fungal composition and bacterial communities in different mineral-filled mesh bags buried in forest soil. Control (filled with quartz, which has little nutrients for plants) and mineral (apatite, potash feldspar and serpentine) -filled mesh bags were buried in E-horizon soil for six months. After incubation, the contents of available elements in bags were determined, bacterial population sizes were quantified by quantitative PCR, and bacterial and ECM fungal community structures in mesh bags were assessed using high-throughput sequencing. The results showed that dozens of ECM fungal species colonized in different mesh bags, of which 17, 54 and 47 ECM species were observed in apatite-, potash feldspar- and serpentine-filled bags, respectively. Ectomycorrhizal fungal composition and bacterial community structure are affected significantly by mineral types. Pseudomonas, Sphingomonas, Bacillus and Paenibacillus, known for high weathering potential, were the preponderant bacteria in mineral-filled bags compared to the control. Ectomycorrhizal fungi are able to selectively colonize mesh bags based on mineral types, and may have a certain influence on the formation of bacterial community structure, implying a possible cooperation of ECM fungi and bacteria in soil mineral weathering.