Bacterial strains to build the synthetic community used in this study.

* isolated by C. Knief from M. truncatula (#613) and A. thaliana (#964 and #968).aRelative fluorescence intensity determined by ARISA of the community colonizing Col-0 plants two weeks after inoculation (weighted mean ± weighted standard deviation, 10 biological replicates).b16S rRNA gene copy number determined by Southern blot analysis.c16S rRNA gene copy number based on the genome sequence.dOne-week old plants were inoculated with single isolates and mean population was estimated two weeks post-inoculation (n = 6 plants).