Exposure to fungicide difenoconazole reduces the soil bacterial community diversity and the co-occurrence network complexity

Difenoconazole is a triazole fungicide that is widely used worldwide and has been frequently detected in agricultural soils, but its ecotoxicological effect on soil bacterial community remains unknown. Here, the degradation of difenoconazole and its effect on soil bacterial communities were investigated at three concentrations in five different agricultural soils. Difenoconazole degraded faster in non-sterilized soils than in sterilized soils, suggesting that biodegradation is a major contributor to the dissipation of difenoconazole in soils. Exposure to high concentrations of difenoconazole decreased the soil bacterial community diversity in most soils, and this influence was aggravated with the increasing concentration. The effect of difenoconazole on soil bacterial community diversity was also enhanced with the increasing content of organic matter and total nitrogen in soils. Moreover, difenoconazole exposure also reduced the soil bacterial community network complexity and exhibited a concentration-dependent characteristic. In addition, a core bacterial community (57 operational taxonomic units, OTUs) was identified, and some core OTUs were strongly linked to the degradation of difenoconazole in soils. It is concluded that high concentrations of difenoconazole may have a significant effect on the soil bacterial communities, and co-occurrence networks may improve the ecotoxicological risk assessment of fungicides on soil microbiome. [Display omitted] •Biodegradation mainly contributed to the dissipation of difenoconazole in soil.•Difenoconazole exposure decreased the soil bacterial community diversity.•Effect of difenoconazole on soil bacterial diversity relied on edaphic factors.•Difenoconazole reduced the soil bacterial co-occurrence network complexity.•Some core OTUs were strongly linked to the degradation of difenoconazole in soil.