Differential responses of gcd‑, phoD‑ and phoR‑harboring bacterial communities to P addition in the soil of Pinus massoniana plantations

The functional genes gcd , phoD , and phoR , which mediate inorganic phosphorus (P) solubilization, organic P mineralization, and P—starvation gene expression, respectively, serve as key proxies for microbial involvement in soil P cycling. However, how P addition shapes the communities of bacteria harboring these genes remains poorly understood. We conducted a one-year P addition experiment in a near-mature Pinus massoniana plantation and characterized the gcd -, phoD - and phoR -harboring bacterial communities using metagenomic sequencing. P addition had no significant effect on the α‑diversity and relative abundance (RPKM) of gcd , phoD , and phoR genes . PCoA indicated slight differences in the community structures of gcd ‑, phoD ‑, and phoR ‑harboring bacteria among P addition treatments ( R 2 = 0.3, p > 0.05). P addition significantly increased the relative abundance of Terracidiphius and Rhodopila in the gcd -, phoD - and phoR -harboring bacterial communities ( p < 0.05). RDA revealed that soil P fractions and physicochemical properties collectively explained 17%–35% ( R adj 2 = 0.17–0.35) of the variation in the community composition of gcd ‑, phoD ‑ and phoR ‑harboring bacteria, with MBP, NN, C.HCl-Po and Residual-P identified as major environmental variables of community structure. P addition increased the complexity of the co-occurrence network, as indicated by more nodes, edges, average path length and modules. AP was the central nodes of the gcd ‑, phoD ‑ and phoR ‑harboring bacterial communities, with its degree in the two‑way network increasing by 6.06%–233.33%. Our study provides new insights into the responses of microbial consortia mediating P solubilization, mineralization, and starvation to P addition in subtropical plantation ecosystems.