Membrane Lipid Remodeling Modulated Maize Response to Environmentally Relevant Atmospheric Nanoplastics

Atmospheric nanoplastics are emergingly found to deposit on leaves of terrestrial plants and adversely affect plant growth. Lipid remodeling has been verified as one of the important strategies for plants to respond to abiotic stress; however, its molecular response to atmospheric nanoplastics in crop leaves remains unclear. In this study, maize leaves were exposed to 50 nm polystyrene nanoplastics (PSNPs) with pristine (nPS), carboxy (nPS-COOH), and amino groups (nPS-NH₂) at environmentally relevant doses (1 and 10 μg/d). Ten-day exposure of nPS-NH₂ induced the strongest phenotypic and physiological inhibition regardless of the exposure dose. All PSNPs were internalized into maize leaves via the stomatal pathway, accumulating dose-dependently. Meanwhile, the highest PSNP absorption efficiency was found in nPS-NH₂ treatment (0.208%), which was 3.92- and 2.37-fold of those in the treatments of nPS and nPS-COOH, respectively. The significant inhibitory effect of three PSNPs on the biosynthesis of 31 membrane "structural" and "signaling" lipids and their gene expression in maize leaves was found through lipidomics and transcriptomics analysis. Five key genes (LACS4, GPAT2, LPP2, DGK1, and PLD1) involved in membrane lipid metabolisms were identified by weighted gene coexpression network analysis. These findings provide valuable insights into the interactions between atmospheric NPs and crop growth from the molecular perspective of lipid remodeling.