Taxonomic structure and functional assembly of the broad-spectrum sulfonylurea herbicide-degrading microbial consortium L1 under different herbicide substrates

The overuse of sulfonylurea herbicides (SUHs) in agricultural environments has resulted in severe residues that damage ecosystems and harm human health. In this study, we described a microbial consortium L1, capable of broad-spectrum degradation of SUHs, which degraded 200   mg   L -1 of bensulfuron-methyl, chlorimuron-ethyl, metsulfuron-methyl, tribenuron-methyl and thifensulfuron-methyl by 81.27%, 97.59%, 62.34%, 72.06% and 100%, respectively, within 7 days. The 16S rDNA and metagenome sequencing results showed that the dominant genera in consortium L1 under different SUHs were concentrated in Methyloversatilis , Pseudoxanthomonas and Chitinophaga . However, the diversity and structure of consortium L1 varied significantly under different SUHs, reflecting differences in both abundant and rare taxa, which could also interconvert. KEGG annotations showed that consortium L1 had the same functional composition when degrading different SUHs, but the number of gene annotations was significantly different, with benzoate degradation (ko00362) being the most enriched of all treatments. Furthermore, the results showed that functional redundancy existed in degradation high contribution genera, with abundant taxa having a greater impact on the degradation of different SUHs. Additionally, network analysis revealed that both rare and abundant genera had more positive edges, suggesting that the strains engaged in more mutualistic or symbiotic cooperation during the degradation process. More importantly, rare taxa play an important role in connectivity between modules. Overall, the assembly of abundant and rare taxa communities and functional composition were closely related to broad-spectrum consortium degrading. These findings deepen the understanding of bacterial consortia and provide valuable insights to enhance their potential in environmental remediation.