Rhizosphere interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungus (Funneliformis mosseae) promote utilization efficiency of phytate phosphorus in maize

• Use of non-phosphorus active soil (OECD) to assess the interactive impacts of earthworms and AMF on phytate mineralization and maize P uptake.
• Earthworms and AMF enhance the mineralization and improve the phytate-P utilization by regulating the soil bacterial diversity, which affects the soil microbial biomass P and alkaline phosphatase activity.
• Earthworms and AMF can interact to enhance the utilization efficiency of phytate-P in maize shoots and roots due to AMF hyphae acquiring P released by earthworms and transferring it to the host plant.

Rhizosphere interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungus (AMF, Funneliformis mosseae), suggested to promote phytate mineralization and maize phosphorus (P) content were studied in the Organization for Economic Co-operation and Development (OECD) (non-phosphorus active soil). Maize was planted and amended with AMF and/or earthworms (E) as well as insoluble phytate-P (C6H18O24P6), in comparison to not amended maize (control). The maize shoot and root biomass, shoot and root P uptake, soil alkaline phosphatase activity, soil microbial biomass P, available P, and the Shannon–Wiener index (H) for the bacterial communities from T-RFLP profiles were measured at harvest. The results indicated that both AM and AM + E treatments significantly increased the utilization efficiency of phytate-P in maize. Our results suggest there are significantly positive interactions between earthworms and AMF in terms of promoting the utilization efficiency of phytate-P in maize and enhancing soil microbial biomass P and alkaline phosphatase activity. The positive interaction enhanced soil microbial biomass P and alkaline phosphatase activity by regulating the bacterial diversity in the soil. The bacterial diversity was significantly correlated with alkaline phosphatase activity, shoot and root P content, biomass and the utilization efficiency of phytate-P. Additionally, alkaline phosphatase activity was positively correlated with microbial biomass P. Flavobacteriaceae and Xanthomonadales, which were the dominant bacteria under all conditions. A significant correlation was observed between Flavobacteriaceae and alkaline phosphatase activity as well as shoot P content, and there was also a significant correlation between Betaproteobacteria and the root and shoot P content. Earthworm and AMF interaction could enhance the phytate-P mineralization in the belowground and improve linking between the aboveground and belowground for phytate-P utilization.