Engineered nanomaterials modulate arbuscular mycorrhizal symbiosis and rhizosphere functions: implications for plant growth and stress resilience

Arbuscular mycorrhizal fungi (AMF) form symbioses with plant roots that significantly enhance host nutrient acquisition and stress tolerance. Engineered nanomaterials (ENMs) can modulate this symbiosis; however, existing studies report highly variable outcomes, and a systematic, quantitative synthesis of the dose-response patterns and holistic interaction mechanisms is currently lacking. Here, we used a bibliometric analysis to document the paradigm shift in ENM-AMF research from early ecotoxicity assessments to nano-enabled growth promotion, followed by a quantitative meta-analysis to assess the concentration-dependent effects of ENMs on plant-AMF symbiosis. Meta-regression demonstrates dose-dependent responses of AMF-colonized plants to ENMs, with low concentrations promoting plant growth, photosynthetic traits and nutrient accumulation and high concentrations exerting inhibitory effects. At low doses, ENMs may promote plant growth by enhancing AMF colonization, increasing rhizosphere nutrient availability and recruiting beneficial microorganisms, thereby strengthening nutrient acquisition and exchange within the plant-AMF symbiosis. Furthermore, ENMs enhance plant tolerance to biotic and abiotic stresses by promoting AMF colonization and function, activating plant defense signaling pathways, and strengthening antioxidant capacity and ion homeostasis. Crucially, this study introduces an integrated framework linking ENMs effects on AMF colonization, plant physiological responses, and rhizosphere microecological processes, addressing the limitations of previous fragmented evaluations. These findings offer both a theoretical basis and quantitative benchmarks for optimizing the combined application of nanomaterials and mycorrhizal resources based on application concentration, thereby laying a scientific foundation for green and sustainable agricultural development.