Transmembrane uptake of polystyrene nanoplastics mediated by aquaporin in tartary buckwheat: Physiological consequence and genomic mechanism

It is still unclear how polystyrene nanoplastics (Ps-NPs) go through plant cell, and its physiological consequence and molecular mechanisms. To address this issue, the seedlings of tartary buckwheat (Fagopyrum tataricum) were exposed to hydroponic solution with 100 mg/L fluorescent-labeled Ps-NPs (100-nm diameter) across 0-2-4-6-8 days. Laser confocal microscopy, scanning electron microscopy and transmission electron microscope illuminated that Ps-NPs can go through root cells and cause significant physiological responses with time. Substantial redox reactions in root cells were significantly negatively associated with plant physiological parameters. Particularly, reactive oxygen species content rapidly increased with time, which activated the differential overexpression of specific aquaporin family genome (transcriptome analyses). Gene expression network analyses demonstrated that the aquaporin FtPIP2;8 (FT01Gene33590.t1) was identified as a core gene, mediating transport proteins or co-factors to drive the across-membrane transport of Ps-NPs. Moreover, there existed a clear co-localization and molecular docking simulations of FtPIP2;8 and Ps-NPs, a key mechanism causing above events, and it revealed the potential regulatory module of FtERF98-FtPIP2;8 by co-expression network analysis and dual luciferase reporter experiment. Here, we provided a key genomic mechanism regarding the targeted transport proteins activated by Ps-NPs for understanding environmental risk of Ps-NPs.