Diflufenican Perturbation Reshapes Bacterial Community Structure and Alters Functional Potential Across Agricultural...

Diflufenican is a herbicide widely used in agricultural systems, but its effects on soil bacterial communities across different soil depths remain insufficiently understood. In this study, we investigated depth-resolved bacterial community responses and functional potential following diflufenican perturbation in agricultural soils. Soil samples collected from different depths were incubated with or without diflufenican, and bacterial communities were analyzed using 16S rRNA gene amplicon sequencing. Co-occurrence network analysis was conducted to explore potential bacterial association patterns, and PICRUSt2 and FAPROTAX were used to infer bacterial functional potential. Diflufenican perturbation altered bacterial alpha diversity and reshaped community composition, with response patterns varying among soil depths. Principal coordinate analysis based on Bray-Curtis dissimilarity showed separation between control and diflufenican-treated soils, indicating treatment-associated shifts in bacterial community structure. Several genera, including Sphingomonas, Pseudarthrobacter, Bacillus, Microvirga, and Phenylobacterium, were enriched in diflufenican-treated soils, suggesting that they may represent candidate diflufenican-associated taxa. Co-occurrence network analysis further indicated changes in potential bacterial association patterns after diflufenican perturbation. Functional inference suggested shifts in bacterial functional potential, particularly in nutrient cycling-related functions, and these shifts differed among soil depths. Overall, these findings indicate that diflufenican perturbation reshapes soil bacterial community structure and alters inferred functional potential in a depth-dependent manner, highlighting the importance of soil vertical depth in assessing herbicide impacts on agricultural soil microbiomes.