Fig. 1

Main research questions (a) and experimental setup (b). a Main research question of the current study. Q1: Do different microbial soil communities lead to differences in phyllosphere communities? Q2: Do different microbial soil communities lead to differences in aphid communities? Q3: Does aphid feeding alter phyllosphere microbial communities? Q4: Does aphid feeding alter soil microbial communities? Assembly processes are depicted as solid arrows, and potential feedback effects are depicted as dashed arrows. b Conceptual figure of experimental design, including soil community preparation. The substrate was standardized in physicochemical properties by combining all soils, but with all soils sterilized except for one providing soil community inoculum (bottom). Black arrows indicate DNA extraction for amplicon sequencing of the corresponding microhabitat. ⁺: wilted seedlings and corresponding aphids were removed from the sampling process; therefore “n” refers to the total number of successfully assessed metagenome samples (phyllosphere and aphid samples) or the number of replicate samples per soil in clayey, mixed, and sandy soil microbiomes. *Ten “inoculum” replicates were drawn from microcosms before planting, five replicates per soil type going to be the substrate for aphid-infested plants, and five replicates going to be in the control group