Impact of phosphorus supply and arbuscular mycorrhizal fungi inoculation on rhizosphere fungal communities and growth of Macadamia integrifolia seedlings

Introduction: in subtropical soils, despite intrinsic adaptations such as cluster roots and rhizosphere P mobilization. However, the role of arbuscular mycorrhizal fungi (AMF) in enhancing P acquisition under varying P availability and inoculum identity remains unclear. Methods: ), assessing seedling growth, biomass allocation, organ-level P concentrations, rhizosphere soil properties, and fungal community composition. Results: inoculation under P1 increased aboveground biomass by 42.9% and root P concentration by 18.4%, whereas the indigenous AMF consortium enhanced leaf P and rhizosphere P under low-P conditions. AMF colonization was strongly associated with total plant biomass but decoupled from short-term P uptake efficiency. Rhizosphere fungal α-diversity and community composition varied with P supply and AMF identity, with Glomeromycota enrichment and reduced saprotroph abundance in inoculated treatments. Discussion: These findings demonstrate context-dependent AMF effects that integrate strain-specific functional traits with intrinsic plant P-acquisition strategies, highlighting functional differentiation between growth promotion and immediate nutrient acquisition. This study provides quantitative guidance for optimizing growth and P-use efficiency in low-P-adapted woody crops.