Resistome dynamics in soil exposed to the herbicide Smetolachlor

Soil microbiota is essential for maintaining soil health. Pesticides that disrupt microbial activities impair soil quality and harm the environment. Bacteria play a significant role in metabolizing chloroacetanilide pesticides. However, herbicide exposure induces environmental stress, triggering adaptive mechanisms such as horizontal gene transfer, which accelerate the establishment and spread of resistance. Surviving in pesticidecontaminated fields, bacteria become highly tolerant to pesticides/heavy metals and simultaneously resistant to antibiotics. The goal of this study was to determine real-life impact of chloroacetanilide herbicide Smetolachlor on antibiotic resistance gene (ARG) abundance in herbicide-treated and untreated soils. The soil from experimental fields sown with maize was sampled 1 week before and 4 weeks after spring spraying. The herbicide content in the soil was determined by LC-MS. Total metagenomic DNA was isolated from the treated and control samples and shortread shotgun sequencing was performed on the DNBSEQ-G400 platform (MGI). After the bioinformatics processing of sequences assembled contigs were checked against the CARD database with ResFinder/RGI. Preliminary analyses suggest notable differences in ARGs distribution before and after herbicide treatment, as well as between treated and control plots. These differences likely reflect the mobility and persistence of the herbicide under real-life agricultural conditions. Our study highlights the potential of herbicide to influence soil microbiome by disrupting microbial community’s structure and potentially promoting antibiotic resistance and selecting resistant genes. This interaction raises concerns about the widespread use of herbicides in agriculture, as it may undermine antibiotic effectiveness, posing a threat to public health and global efforts to combat resistance.