Abstract

The microbial communities inhabiting the interior of roots of healthy plants, as well as the rhizosphere, i.e., particles of soil firmly attached to roots, engage in symbiotic associations with their host. We employed a combination of 16S rRNA gene profiling and shotgun metagenome analysis to investigate the structural and functional diversification of the microbiota associated with wild and domesticated accessions of barley (Hordeum vulgare). Analyses of beta-diversity based on the 16S data revealed a small but significant genotype effect on the root-associated communities. In addition, functional characterization of metagenome samples allowed us to identify functional categories enriched in the rhizosphere of barley as well as protein families with evidence of being under positive selection. Our results indicate that the combined action of microbe-microbe and host-microbe interactions drives microbiota differentiation at the root-soil interface.