Environmental Restoration: Managing Y₂O₃ Nanoparticle Soil Pollution Through Sustainable Mycorrhizal Strategies

Environmental toxicity from metal oxide nanoparticles (NPs) such as yttrium oxide NPs (Y₂O₃ NPs) poses a significant threat to crop productivity in agroecosystems. To evaluate the potential mitigating role of arbuscular mycorrhizal fungi (AMF), oat (Avena sativa L.) and soybean (Glycine max L.) plants were grown with or without AMF inoculation under Y₂O₃ NP exposure conditions. Y₂O₃ NPs caused severe growth and photosynthetic inhibition, with oat being more sensitive than soybean: shoot biomass decreased by 50%-75% in oat versus 30%-40% in soybean, and photosynthetic parameters dropped by 65%-70% in oat and 20%-35% in soybean. These effects were associated with pronounced oxidative stress, depletion of ascorbate and glutathione pools in oat, and species-specific induction of antioxidant and phenylpropanoid pathways. Soybean maintained relatively higher photosynthetic capacity, enabling stronger upregulation of antioxidant defences (phenolics, anthocyanins) and detoxification mechanisms (phytochelatins, metallothioneins, and glutathione S-transferase activity), reflecting a more robust thiol- and chelator-based detoxification system. AMF improved growth and photosynthetic performance in both species and partially alleviated NP-induced oxidative damage, but its protective effect was significantly stronger in soybean than in oat. Multivariate analysis showed that phenylpropanoid reprogramming and antioxidant capacity shaped species-specific responses. These findings suggest that maintenance of physiological and redox stability plays an important role in species-specific tolerance to Y₂O₃ NP exposure, while AMF inoculation partially moderates stress-related physiological and metabolic disruption.