Effect of Inoculation with Arbuscular Mycorrhizal Fungi (Rhizophagus irregularis BGC AH01) on the Soil Bacterial Community Assembly

Soil bacterial communities are crucial drivers of nutrient cycling and ecosystem functioning; however, their temporal dynamics under arbuscular mycorrhizal (AM) fungi colonization remain insufficiently characterized. In this study, we used a non-destructive continuous sampling method and undertook a 90-day pot experiment to examine the process of shaping the bacterial community of hyphosphere soil. Following inoculation with AM fungi, we found an increase in the α-diversity index of the hyphosphere bacterial community. The community diversity and richness and the key bacterial taxa in the hyphosphere both gradually increased from 30 to 60 days and stabilized thereafter. Principal coordinated (PCoA) analysis and network analysis further confirmed these findings. Stabilized by 60 days post-inoculation, with deterministic processes dominating assembly in inoculated AM fungi soils, while stochastic processes prevailed in non-inoculated controls. Inoculation strengthened bacterial associations with available phosphorus, while making the key bacterial communities more responsive to multiple soil physicochemical properties (available P, CEC, N, and TOC). These findings provide critical insights into AM fungi mediation of soil microbiome dynamics, with the identified 60-day stabilization period offering a key temporal framework for understanding tripartite soil-AM fungi-bacteria interactions.