Arbuscular mycorrhizal fungi in microplastic-contaminated agricultural soils: reciprocal interactions, context dependence and precision mycorrhizal remediation

Microplastics (MPs) are persistent, heterogeneous soil contaminants with effects on agricultural systems that depend on polymer identity, particle size and morphology, concentration, aging, soil properties and co-occurring stressors. Arbuscular mycorrhizal fungi (AMF) are situated in the soil-root interface and are able to respond to MP exposure and alter particle fate and plant responses. Agricultural and experimental systems suggest that MPs can modulate AMF colonization, fungal vitality and community composition, but responses are not uniformly suppressive. AMF can also modify MP movement and plant exposure through hyphal interception, particle retention, modified rhizosphere transport, and changes in root-to-shoot allocation. The effects were strongly particle dependent: AMF reduced the uptake or translocation of some PET, PMMA and larger particles but increased the uptake of other polymers or smaller particles. Nanoplastics (NPs) broaden these interactions to direct effects on spores, hyphae, organelles and plant–fungus signalling. The emerging literature thus supports a reciprocal, scale-dependent model rather than a simple contaminant–microbe toxicity framework. This review integrates the factors that influence MP-AMF interactions, assesses implications for AMF establishment and symbiotic functioning, and advances the concept of precision mycorrhizal remediation (PMR). PMR is defined as a site-specific, trait-based and risk-oriented approach where native or selected AMF are matched to MP characteristics, soil conditions, host plants and co-contaminants. In this framework, remediation refers to the biological management of contaminant exposure and associated ecological dysfunction, not to the physical removal or chemical degradation of plastic polymers. The primary objectives are to reduce biologically relevant exposure, maintain symbiotic functioning and stabilize soil–plant processes. Standardized particle characterization, functional AMF phenotyping, native-community comparisons and field validation are needed before PMR can move from a conceptual framework to operational management.