A study published in Nature (2014) explores how bacterial phylogeny influences the structure of soil resistomes across different habitats. Researchers identified 2895 antibiotic resistance genes (ARGs) from 18 agricultural and grassland soils, most of which were novel and represented all major resistance mechanisms. The study found that distinct soil types harbored distinct resistomes, with nitrogen fertilizer amendments significantly affecting ARG content. Resistome composition correlated with microbial phylogenetic and taxonomic structure, suggesting that ARGs in soil may not transfer between bacteria as readily as in clinical settings. Functional metagenomic selections allowed the identification of full-length, functionally-verified ARGs, revealing that soil ARGs were largely dissimilar from those in public repositories. The study also showed that soil resistomes were enriched in certain resistance mechanisms, such as β-lactamases, and that ARGs in soil were less likely to be horizontally transferred compared to those in human pathogens. The research highlights that bacterial community composition is the primary determinant of soil ARG content, challenging previous hypotheses that horizontal gene transfer decouples resistomes from phylogeny. The findings suggest that soil resistomes are shaped by bacterial diversity and phylogeny, rather than by horizontal gene transfer. The study also demonstrated that soil ARGs have limited genetic potential for horizontal exchange, which may explain why ARGs are rarely shared between soil and human pathogens. The research provides insights into the functional diversity of soil resistomes and their relationship with bacterial communities.A study published in Nature (2014) explores how bacterial phylogeny influences the structure of soil resistomes across different habitats. Researchers identified 2895 antibiotic resistance genes (ARGs) from 18 agricultural and grassland soils, most of which were novel and represented all major resistance mechanisms. The study found that distinct soil types harbored distinct resistomes, with nitrogen fertilizer amendments significantly affecting ARG content. Resistome composition correlated with microbial phylogenetic and taxonomic structure, suggesting that ARGs in soil may not transfer between bacteria as readily as in clinical settings. Functional metagenomic selections allowed the identification of full-length, functionally-verified ARGs, revealing that soil ARGs were largely dissimilar from those in public repositories. The study also showed that soil resistomes were enriched in certain resistance mechanisms, such as β-lactamases, and that ARGs in soil were less likely to be horizontally transferred compared to those in human pathogens. The research highlights that bacterial community composition is the primary determinant of soil ARG content, challenging previous hypotheses that horizontal gene transfer decouples resistomes from phylogeny. The findings suggest that soil resistomes are shaped by bacterial diversity and phylogeny, rather than by horizontal gene transfer. The study also demonstrated that soil ARGs have limited genetic potential for horizontal exchange, which may explain why ARGs are rarely shared between soil and human pathogens. The research provides insights into the functional diversity of soil resistomes and their relationship with bacterial communities.