Exploring biochar-mediated remediation of tetracycline-contaminated soil via a metagenomic approach: insights into soil microbial community and potential functions.

Biochar is widely used as a soil amendment; however, information regarding its effects on soil microbial communities under tetracycline (TET) stress remains limited. In this study, metagenomic sequencing was employed to investigate the effects of TET contamination and biochar amendment on soil microbial community profiles, the abundance of antibiotic resistance genes (ARGs), and carbohydrate-active enzymes (CAZymes) genes through a pot experiment. Results showed that TET exposure reduced microbial diversity and evenness, and significantly altered the relative abundance of dominant microbes (e.g., Acidobacteriota and Candidatus_Rokubacteria) whereas biochar amendment especially at 0.5% application significantly increased both diversity and evenness, facilitated the recovery of dominant microbes, and improved community stability. TET exposure also enriched glycopeptide resistance genes and shifted CAZyme gene profiles. Overall, the metagenomic results demonstrated that reed biochar can regulate soil microbial responses under TET stress, providing insights into its role in alleviating antibiotic-induced microbial disturbance and supporting soil ecological resilience.