Colonization of three Sphagneticola species by Funneliformis mosseae under cadmium stress is beneficial to phosphatase activity and nutrient uptake in rhizosphere soil

BACKGROUND: Soil cadmium (Cd) contamination poses threats to ecosystems and human health, and the plant arbuscular mycorrhizal fungi (AMF) symbiotic system represents a promising green remediation strategy. However, the underlying mechanisms are complex and context-dependent, and systematic comparative studies remain scarce regarding differential regulation of Cd tolerance enhancement in plants of the same genus but different ecotypes. This study used a native species (Sphagneticola calendulacea), invasive species (Sphagneticola trilobata), and their hybrid as materials. It conducted an integrated analysis of the synergistic effects of inoculating Funneliformis mosseae (FM) on the rhizosphere microenvironment and mineral element uptake of three plants under a Cd stress gradient. The objective was to elucidate the interactive mechanisms by which FM enhances plant Cd tolerance and to evaluate its remediation potential. RESULTS: Results indicate that FM regulation of rhizosphere pH exhibits species specificity but generally alleviates Cd induced acidification. FM significantly enhances acid phosphatase activity in rhizosphere soil and substantially promotes plant phosphorus (P) uptake. FM comprehensively altered plant mineral element uptake, including promoting root accumulation of sodium (Na), magnesium (Mg), and calcium (Ca), shoot potassium (K) allocation, and copper (Cu) and zinc (Zn) absorption. CONCLUSIONS: This study elucidates how FM enhances P uptake and systematically optimizes elemental absorption homeostasis by regulating rhizosphere pH and phosphatase activity. These synergistic effects improve Cd tolerance in Sphagneticola species and highlight the broad potential of AMF-plant symbioses for Cd remediation. It provides crucial theoretical foundations and germplasm selection references for targeted soil restoration using ecologically distinct Sphagneticola ecotypes and their optimal FM partners.