PCoA of microbial communities based on Bray–Curtis distance. A PCoA plots for four different AMF inoculation and P-fertilization treatment groups. B PCoA plots for two different P-efficiencies of soybean groups. C PCoA plots for three different sampling compartment groups. The left panel is PCoA of bacterial community while the right panel is PCoA of fungal community. ‘W/t addition’ and ‘AMF + P’ represent ‘no P-fertilization or AMF inoculation’ and ‘AMF inoculation with P-fertilization’, respectively. NY-1001 and PT6 represent the lower P-efficiency recipient soybean ‘NY-1001’ and higher P-efficiency soybean ‘PT6’. SS, RS, and Rt represent surrounding soils, rhizospheric soils, and intact roots, respectively.