Arbuscular mycorrhizal fungi change toxic effects of different types of microplastics on Lactuca sativa L. by influencing plant metabolic processes

Soil microplastics (MPs) pollution is becoming more serious, and symbiotic microorganisms in soil–plant systems may influence the environmental behavior and related plant responses to MPs stress. In this study, common primary plastic products were broken down into MPs to investigate the toxic effects and migration behavior of MPs on lettuce ( Lactuca sativa L.) in the presence of arbuscular mycorrhizal fungi (AMF). Our findings show that symbiotic AMF reduce the uptake and toxic effects of polyethylene terephthalate (PET) by increasing nucleotide metabolism and zeatin biosynthesis, resulting in a 20.64 % drop in PET uptake and an 11.43 % increase in lettuce biomass. In contrast, AMF promoted the absorption of polypropylene (PP) and polystyrene (PS) by lettuce, inhibiting ascorbate metabolism and lysine biosynthesis, and causing poorer lettuce growth. The positive regulatory effect of AMF on the nutritional quality and health status of plants under PET stress shows that AMF have the potential to alleviate the toxicity of MPs to lettuce in farmland and to remediate the MPs-related pollution in agricultural areas. • Arbuscular mycorrhizal fungi inhibit plant uptake of polyethylene terephthalate. • Arbuscular mycorrhizal fungi improve plants health and nutrients quality under polyethylene terephthalate stress. • Arbuscular mycorrhizal fungi promote plants uptake of polypropylene and polystyrene. • Arbuscular mycorrhizal fungi cause a more positive metabolic response to polyethylene terephthalate in plants. • Polypropylene and polystyrene caused negative metabolic response and demonstrated stronger toxicity to plants.