Fig. 4

Non-metric multi-dimensional scaling (NMDS) biplot showing the diversity in bacterial community composition in bulk soil and in lettuce, leek 2018 and leek 2019 rhizosphere soils under different soil treatments and determined via 16S rRNA gene amplicon sequencing (A, n = 5) and shotgun metagenomics (B, n = 3), with dimensions = 2 and stress = 0.078. For (A), differences between bulk and all rhizosphere soils were significant at the level of P < 0.001 (ANOSIM, R = 0.852) and between lettuce, leek 2018 and leek 2019 rhizosphere soils at the level of P < 0.001 (R = 0.821), and between leek 2018 and leek 2019 rhizosphere soils at the level of P < 0.001 (R = 0.384). For (B), differences between bulk and all rhizosphere soils were significant at the level of P < 0.001 (ANOSIM, R = 0.4307) and between individual rhizosphere soils at the level of P < 0.001 (R = 0.3294)