Impact of Tetracycline Stress on Water Quality and Rhizosphere Microbial Communities of Eichhornia crassipes: Implications for Bioremediation

To examine the impact of antibiotic contamination on water quality and rhizospheric microbial communities, a simulated cultivation experiment was employed to investigate the potential impacts of tetracycline (Tet) stress on water quality and microbial community composition in the rhizosphere of <i>Eichhornia crassipes</i> (<i>E. crassipes</i>), with a focus on its implications for bioremediation strategies. The results showed a significant disruption in microbial diversity and community structure in the rhizosphere at varying accumulated Tet concentrations (0, 2, 5, and 10 mg·L^-1). The microbial communities displayed resilience and functional stability from the low (2 mg·L^-1) to moderate (5 mg·L^-1) accumulated Tet concentrations; while significant root decay and a marked decline in microbial diversity were observed at the high (10 mg·L^-1) accumulated Tet concentration. Some bacterial taxa, including Rhizobiaceae (0.34%), Comamonadaceae (0.37%), and Chitinophagaceae (0.38%), exhibited notable enrichment under Tet stress, underscoring their functional roles in nitrogen cycling, organic matter decomposition, and antibiotic degradation. Physicochemical changes in the rhizosphere, such as shifts in low-molecular-weight organic acids (LMWOAs), nutrient cycling, and total organic carbon (TOC), revealed Tet-induced metabolic adaptations and environmental alterations. Correlation analysis between environmental factors and dominant operational taxonomic units (OTUs) highlighted the putative intricate interplay between microbial activity and Tet stress. These findings underscore the dual impact of Tet as both a stressor and a selective agent, favoring antibiotic-resistant taxa while suppressing sensitive groups. This study provides foundational insights into the ecological and functional dynamics of microbial communities under antibiotic contamination conditions and highlights the potential of rhizospheric microbial communities in the rhizosphere for bioremediation in Tet-polluted ecosystems.