Microbial diversity in bulk soil (16S/ITS RNA sequencing) from different soil histories and plant species

Plants are known to influence belowground microbial communities, which in turn drive nutrient cycling, plant productivity and the maintenance of plant diversity. However, how plant diversity and plant community age affect soil microbial diversity and community composition in in the bulk soil is largely unknown. Here, we used 16S and ITS sequencing to analyze soil microbial communities under new vs. old plant communities on new vs. old soils. "Old" here refers to plants and soil taken from an eight-year old biodiversity experiment (the Jena Experiment in Germany), and "new" to plants without community history and soil from which community history was removed by sterilization. Plant species richness ranged from 1, 2, 4, 8 to 60 sown species. Our results show a weak relationship between aboveground diversity and soil diversity, but microbial community composition differed between monocultures and mixtures. Soil legacy increased soil microbial diversity (bacterial richness and evenness) more strongly than plant community age, but the latter significantly affected 10% of fungal OTUs. Our findings suggest that plant communities can select for a specific microbiome and for interactions between certain plant species and their associated microbial species.