Confocal composite Z-stack images of B. dactyloides roots grown in T2 with no compost (A), T2 with 5% compost (B), T2 with 10% compost (C), Vinton soil with no compost (D), Vinton soil with 5% compost (E), and Vinton soil with 10% compost (F). Magnification, ×100; bar, 10 μm. FISH analysis was performed with the universal EUB338 probe mix labeled with Cy5.