A synthetic microbiome drives a multi-omics response to remediate 1,4-dithiane-contaminated soil and simultaneously suppresses antibiotic resistance genes.

1,4-Dithiane, a degradation product of abandoned Japanese chemical weapons, is a persistent organic pollutant with ecological risks. A synthetic microbiome (SM) was constructed through pollution stress screening and ratio optimization, consisting of Shinella sp., Alcaligenes faecalis, Sphingomonas sp., and Stenotrophomonas sp. at an optimal ratio of 1: 1: 2: 2. The SM achieved a 1,4-dithiane degradation rate of 95.2% and reduced intermediate accumulation. Soil remediation experiments showed complete pollutant removal within 60 days, along with improved soil health: reduced bioavailability of heavy metals (Cu, Zn, Cd), increased pH (6.47-6.95), elevated organic matter and enzyme activities, and decreased salinity and redox potential. Integration of ionomics, 16S sequencing, metagenomics, metabolomics, and HT-qPCR revealed that SM colonization reshaped microbial community structure, suppressed ARG-harboring bacteria (e.g., Pseudomonas), and activated core pathways (oxidative phosphorylation and glutathione metabolism), enhancing metabolic activity and oxidative stress tolerance. Consequently, the diversity, abundance, and diffusion potential of soil ARGs and mobile genetic elements were significantly reduced. These findings provide microbial solutions and a theoretical basis for concurrent organic pollution control and soil ecological risk management.