soil antibiotic resistance genes and carcass decomposition

As a common natural phenomenon, corpse decomposition may lead to serious environmental pollution such as nitrogen pollution. However, less is known about antibiotic resistance genes (ARGs), an emerging contaminant, during corpse degradation. Here, ARGs and microbiome in three soil types (black, red and yellow soil) had been investigated between experimental groups and control groups based on next-generation sequencing and high-throughput quantitative PCR techniques. We found that corpse decomposition raised the absolute abundance of total ARGs and MGEs were respectively enriched 536.96 and 240.60 times in different soil types, and the number of ARGs in experimental groups was 14-25 more than that in control groups. For experimental groups, the distribution of ARGs was distinct in different soil types, but sulfonamide resistance genes were always enriched in all experimental groups. Corpse decomposition was a primary determinant for ARGs profiles. Microbiome, NH4+ concentrates and pH also significantly affected ARGs profiles. Nevertheless, the soil type had few effects on ARGs profiles. For soil microbiome, some genera were elevated in experimental groups such as the Ignatzschineria and Myroides. The alpha diversity is decreased in experimental groups and microbial community structures are different between experimental and control groups. Additionally, the Escherichia and Neisseria were potential pathogens elevated in experimental groups. Network analysis indicated that most of ARGs like sulfonamide and multidrug resistance genes presented strong positively correlations with NH4+ concentrates and pH, and some genera like Ignatzschineria and Dysgonomonas were positively correlated with several ARGs such as aminoglycoside and sulfonamide resistance genes. Our study reveals a law of ARGs' enrichment markedly during corpse decomposing in different soil types, and these ARGs contaminant maintaining in environment may pose a potential threat to environmental safety and human health