Polyethylene microplastics induce microbial functional reprogramming via rhizosphere network disruption, accelerating...

Polyethylene microplastics (PE-MPs) are emerging soil pollutants with unclear mechanisms of impact on rhizosphere ecosystem functions. Using Angelica sinensis, a medicinal plant valued for its root use, as a model, this study integrated untargeted metabolomics, metagenomic sequencing, and PLS-PM modeling to investigate rhizosphere responses to different PE-MPs concentrations (250, 500, 1000 mg/kg). With increasing PE-MPs dosage, rhizosphere metabolic pathways shifted toward stress adaptation, featuring functional homeostasis and energy reprogramming. Exposure to PE-MPs significantly altered microbial community structure: bacterial and viral shannon, richness, and pielou evenness indices increased, fungal dominance and reduced evenness were observed, and archaeal diversity indices declined. Microbial network stability and functional redundancy weakened, increasing ecosystem sensitivity. Metabolite-microbe association analysis revealed synergistic enrichment patterns, suggesting that plants may recruit beneficial microbes through metabolite regulation. The PLS-PM modeling results indicated that metabolite changes regulate the expression of C/N/S/P cycling functional genes through shifts in bacterial and viral community compositions, where bacteria serve as the primary regulatory hubs and viruses play a key role in amplifying microbial signaling by influencing the microbial community. The expression of these functional genes was negatively correlated with the Soil Quality Index (SQI), indicating that PE-MPs-induced metabolic stress accelerates soil functional degradation. This study provides new insights into microplastic-driven rhizosphere disruption and offers a theoretical basis and biomarkers for microbial regulation and soil ecological restoration.