show Abstracthide AbstractHere, we studied the endophytic bacterial microbiome of perennial wheatgrass in comparison with annual wheat in a pan-European gradient. Samples were collected from two plant genotypes (Thinopyrum intermedium L. and Triticum aestivum L.), three compartments (roots, stems, and leaves), three sampling sites (France-St. Marcel, Belgium-Gembloux, Sweden-Lönnstorp), and two harvest years (June 2021 and April 2022). Samples were surface sterilized, DNA was extracted, the 16S rRNA gene fragment (V3-V4) was amplified and the amplicons were sent for high-throughput sequencing. In total, 704 samples were successfully amplified and sequenced.