diversity Article Definition of Core Bacterial Taxa in Different Root Compartments of Dactylis glomerata, Grown in Soil under Different Levels of Land Use Intensity Jennifer Estendorfer 1, Barbara Stempfhuber 1,*, Gisle Vestergaard 1,2 , Stefanie Schulz 1, Matthias C. Rillig 3 , Jasmin Joshi 4 , Peter Schröder 1 and Michael Schloter 1,5 1 Research Unit Comparative Microbiome Analysis, Helmholtz Zentrum München, 85764 Neuherberg, Germany 2 Department of Health Technology, Technical University of Denmark, 2800 Lyngby, Denmark 3 Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany 4 Eastern Switzerland University of Applied Sciences, ILF Institute for Landscape and Open Space—Landscape Ecology, 8640 Rapperswil, Switzerland 5 Chair for Soil Sciences, Technical University Munich, 85354 Freising, Germany * Correspondence:
[email protected]; Tel.: +49-89-3187-2304 Received: 17 August 2020; Accepted: 2 October 2020; Published: 13 October 2020 Abstract: Plant-associated bacterial assemblages are critical for plant fitness. Thus, identifying a consistent plant-associated core microbiome is important for predicting community responses to environmental changes. Our target was to identify the core bacterial microbiome of orchard grass Dactylis glomerata L. and to assess the part that is most sensitive to land management. Dactylis glomerata L. samples were collected from grassland sites with contrasting land use intensities but comparable soil properties at three different timepoints. To assess the plant-associated bacterial community structure in the compartments rhizosphere, bulk soil and endosphere, a molecular barcoding approach based on high throughput 16S rRNA amplicon sequencing was used. A distinct composition of plant-associated core bacterial communities independent of land use intensity was identified.