We performed 4 experiments during which bacterial synthetic communities were inoculated on bean seeds. Experiment 1 : Inoculation of 35 single bacterial strains on bean seeds - Effect on seedling microbiota assembly Experiment 2 : Inoculation of one SynCom (14 strains) on bean seeds - Effect of inoculum concentration, inoculation fluid and seed disinfection on seed microbiota Experiment 3 : Inoculation of one SynCom (14 strains) on bean seeds sown in soil - Effect of inoculum concentration on seedling microbiota assembly Experiment 4 : Inoculation of twelve SynComs of increasing richness (3, 5, 8 or 11 strains) on bean seeds sown in soil - Effect of SynCom richness on seedling microbiota assembly We performed amplicon sequencing on the gyrB gene to characterize bacterial communities on the Illumina MiSeq platform. Embargo on the data in ENA until September 30th 2023.