Fig. S2. Reinoculation of the microbiome back to axenic Lemna minor fronds. The container, filled with natural pond water is filled with fronds from the same site, with their microbiome intact. The floating circular boom isolates the sterilised target fronds. Although the fronds are spatially separated at the water’s surface, the roots intermingle. To reinoculate the microbiome back to the axenic fronds, the target fronds were cultured here for two weeks (about 4 generations).