Perfluorohexane sulfonate (PFHxS) restructures the rhizosphere microbiome of Lupinus polyphyllus

Perfluorohexane sulfonate (PFHxS) is persistent and highly mobile that is increasingly detected in agricultural soils, raising concerns about its long-term ecological impacts on plant-soil systems. Despite its widespread, little is known about how PFHxS restructures rhizosphere microbial communities, modifies microbial ecological interactions, or affects soil biochemical functioning that underpins ecosystem resilience. Using Lupinus polyphyllus as a model legume, this study investigated the effects of PFHxS (5, 25, and 125 mg/kg) on plant performance, soil biochemical functions, and rhizosphere microbial communities, with the latter characterized using high-throughput sequencing and microbial network analyses. PFHxS exposure at 5 mg/kg stimulated plant growth, whereas higher PFHxS concentrations attenuated this growth-promoting effect. Bacterial communities remained comparatively resilient and continued to be dominated by Actinobacteria, Proteobacteria, and Firmicutes, whereas fungal communities exhibited pronounced sensitivity, with Chao1 richness and unique operational taxonomic units (OTU) declining by 50.6% and 69.2%, respectively. Despite the compositional resilience of bacterial communities, Bray-Curtis ordination, heatmap clustering, and microbial network analyses revealed concentration-dependent restructuring of rhizosphere microbial interactions under PFHxS exposure. Collectively, these findings identify fungal communities as the most sensitive component of the rhizosphere microbiome to PFHxS stress and provide new insight into PFHxS-driven rhizosphere responses with implications for ecological risk assessment.