Effects of the Combined Application of Arbuscular Mycorrhizal Fungi and Reconstructed Microbial Communities on Soil Functional Restoration

ABSTRACT Open‐pit mining severely disrupts ecosystems in the Yellow River Basin. Microbial reclamation strategies can accelerate soil functional recovery, yet the mechanisms underlying synergistic interactions between reconstructed microbial communities and arbuscular mycorrhizal fungi (AMF) remain poorly understood. The work elucidated the effects and driving mechanisms of AMF and reconstructed microbial communities on soil functional restoration to promote plant growth and root expansion. It was hypothesized that AMF inoculation combined with reconstructed microbial communities would reshape rhizosphere community assembly through environmental filtering and niche enrichment, which would enrich soil nutrient availability. Six treatments were established using Amorpha fruticosa as the test plant, including (1) control (CK), (2) reconstructed microbial community from 5‐year natural reclamation (S), (3) reconstructed microbial community from 5‐year AMF‐assisted reclamation (F), (4) AMF alone, (5) co‐inoculation of AMF with the 5‐year natural reclamation microbial community (AS), and (6) co‐inoculation of AMF with the 5‐year AMF‐assisted reclamation microbial community (AF). Besides, samples were collected over four growth stages at 15, 30, 60, and 120 days. Soil physicochemical properties, plant nutrient levels, and bacterial community composition and diversity were analyzed using a random forest model. Functional potentials were predicted with Tax4Fun2 at three levels (Level 2, pathway, and KO). The AF treatment demonstrated the strongest synergistic effects, enhancing nutrient acquisition and signal transduction. This promoted soil nutrient availability and plant growth. Compared to the CK, the AF treatment increased available potassium, total potassium, available phosphorus, total phosphorus, and soil organic carbon by 46%, 4%, 17%, 19%, and 26%, respectively. This treatment also resulted in the highest bacterial phylogenetic diversity. Functional predictions indicated that carbohydrate and amino acid metabolism were activated at an early stage. Carbon flow was channeled toward phospholipid and glycosylphosphatidylinositol (GPI)‐anchored biosynthesis pathways, which supported sustained hyphal–root interactions. Functional coupling among membrane transport, signal regulation, and carbon metabolism was established by Day 120. In contrast, the F treatment primarily enhanced membrane transport, whereas the AS treatment prioritized carbon stabilization. These findings provide theoretical support for integrating reconstructed microbial communities into AMF‐based reclamation strategies, which improves the ecological restoration of mining‐impacted soils.