Pesticides are continually entering the soil ecosystem because of safety assurance of high-yield food in agricultural intensification. It is highly urgent to evaluate their effects on the soil biota. This study characterized the dose-dependent changes in the gut bacterial and fungal community of Enchytraeus crypticus after oral exposure to an environmental dose of the fungicide azoxystrobin (AZ; 0.5, 1, and 10 mg/L) for 21 days. AZ not only induced the growth opportunistic pathogens and reduced the relative abundance of beneficial bacteria in the E. crypticus gut, but also destroyed the stability of the gut microecology of E. crypticus. Meanwhile, the dose-dependent effects of AZ were observed on the number and normalized abundance of antibiotic resistance genes (ARGs; copies/bacterial cell), and trace dose of AZ (> 0 and < 0.085 μg/individual) might enrich the ARG numbers in the gut of E. crypticus. Moreover, we used structural equation modeling to speculate that apart from mobile genetic elements and the bacterial community, the microbial interaction of E. crypticus gut might be another key contributor that drived the emergence and dissemination of ARGs. This study provides new perspectives in assessing the gut health of soil fauna under pesticide pollution in intensive agricultural production.

由于农业集约化对高产食品的安全保障，农药不断进入土壤生态系统。评估它们对土壤生物群的影响非常紧迫。本研究描述了在口服环境剂量的杀真菌剂嘧菌酯（AZ；0.5、1 和 10 mg/L）21 天后，隐孢子虫肠道细菌和真菌群落的剂量依赖性变化。AZ不仅诱导了机会性病原体的生长，降低了隐孢子虫肠道中有益菌的相对丰度，而且破坏了隐孢子虫肠道微生态的稳定性。. 同时，观察到 AZ 对抗生素抗性基因（ARGs；拷贝/细菌细胞）的数量和归一化丰度的剂量依赖性影响，微量 AZ（> 0 和 < 0.085  μg/个体）可能会丰富 ARG 数量在E. crypticus的肠道中。此外，我们使用结构方程模型推测，除了移动遗传元件和细菌群落之外，隐匿大肠杆菌肠道的微生物相互作用可能是推动 ARGs 出现和传播的另一个关键因素。本研究为评估集约化农业生产中农药污染下土壤动物的肠道健康提供了新的视角。