Stronger effect of maize rhizosphere than phosphorus fertilization on soil phosphatase activity and associated bacterial communities in acidic soil: distinct influences on phoC- and phoD-harboring bacteria

Abstract

Aims The bacteria phoC and phoD genes encode acid and alkaline phosphatase (ACP and ALP), respectively, which mineralize organic phosphorus (P) to inorganic P. The relative importance of P fertilization and the plant rhizosphere on soil phosphatase activities and associated bacterial communities in acidic soils are poorly understood; whether phoC- and phoD-harboring bacterial communities display different responses remains undetermined. Methods Maize was grown in acidic soil supplemented with 0 (P0), 20 (P20), and 200 (P200) mg P2O5 kg− 1 for 42 days. Maize biomasses, plant nutrients, soil properties, phosphatase activities, and associated bacterial abundance and community composition were determined. Results Relative to bulk soils, rhizosphere showed increased ACP and ALP activities, phoC and phoD gene abundance, but these effects were reduced in strength with P200 treatment, except for phoC gene abundance. The rhizosphere effect increased α-diversity of phoC-harboring bacteria under P fertilization but reduced α-diversity of phoD-harboring bacteria under P0 and P20 treatments. The rhizosphere significantly influenced both phoC- and phoD-harboring bacterial community compositions, with stronger effect on phoD-harboring bacteria; while P fertilization affected phoD-harboring bacteria but not phoC-harboring bacteria. Immigrated and extinct species play important roles in reshaping phoC- and phoD-harboring bacterial communities, respectively, in response to the rhizosphere effect. Conclusions Compared with P fertilization, the maize rhizosphere more strongly influenced soil phosphatase activities and phoC- and phoD-harboring bacterial communities in acidic soils, with phoD-harboring bacteria responding more strongly to the rhizosphere effect and P fertilization. Notably, the strength of the rhizosphere effect heavily relied on P fertilization level.