Synergistic fungal consortia enhance maize growth and soil biological functions under microplastic stress

Polyethylene terephthalate microplastics (PET-MPs) contamination in agricultural soils is an emerging global concern because these persistent particles disrupt soil structure, nutrient dynamics, and plant physiological processes, ultimately threatening crop productivity and food security. Despite their widespread occurrence in agroecosystem, yet their impacts on crop, soil, and microbe interactions remain poorly understood. Beneficial fungi such as Trichoderma and Metarhizium are widely recognized for promoting plant growth and stress tolerance, but their combined potential to alleviate microplastic toxicity has not been systematically evaluated. This study investigated how PET-MPs influence maize growth, redox homeostasis, metabolism, and soil biological functioning, and assessed whether single or combined inoculation with Trichoderma longibrachiatum and Metarhizium anisopliae can mitigate PET - MPs induced stress.

PET - MPs exposure caused strong growth inhibition in maize, with marked decline in biomass, chlorophyll content, and root development, accompanied by enhanced oxidative stress and membrane damage. These physiological injuries were linked to disrupted antioxidant systems, imbalanced redox metabolites, and major reprogramming of root exudates and central carbon metabolism. Soil nutrient availability, enzyme activities, and microbial community structure were also significantly altered. Inoculation with either Trichoderma or Metarhizium partially mitigated these effects, but their co-application produced a stronger response. The fungal consortium most effectively suppressed reactive oxygen species, restored antioxidant and redox homeostasis, and redirected root metabolism toward sugars, organic acids, and carbon release. At the soil level, the combined fungal inoculation enhanced nitrogen transformations, stimulated key enzymes, and promoted a more active and balanced microbial community under PET-MPs stress.

PET-MPs imposes severe physiological, biochemical, and ecological constraints on maize and its rhizosphere. Synergistic inoculation with Trichoderma and Metarhizium effectively counteracts these stresses by reinforcing redox balance, metabolic functioning, and soil biological health. This fungal consortium represents a promising, nature - based strategy for improving crop resilience and sustaining soil quality in PET-MPs contaminated agroecosystems.