Combined effects of acetamiprid and tetraconazole on enzyme activity and gene expression in the earthworm-soil system

• Acetamiprid had a higher acute toxicity to the earthworm relative to tetraconazole. • Acute toxicity of acetamiprid and tetraconazole was elevated by mixture exposure. • CarE activity was induced by the mixture exposure of acetamiprid and tetraconazole. • Mixture stimulated the expression of sod gene compared with individual pesticides. Within an identical soil environment, various pesticides may be commonly identified, but their collective toxicological traits have not been thoroughly investigated. This research sought to elucidate the potential consequences of concurrent exposure to multiple pesticides on soil organisms, with a specific emphasis on examining alterations in transcript and enzyme levels induced by the co-presence of acetamiprid (ACE) and tetraconazole (TET) in earthworms ( Eisenia fetida ). The results indicated that the joint presence of ACE and TET exhibited an acute synergistic impact on the organisms. Notably, there was a significant elevation in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), coupled with a substantial suppression of caspase-9 and caspase-3 contents observed in the majority of both individual and combined groups. These findings suggested the occurrence of oxidative stress and cell death. Furthermore, the study revealed a substantial up-regulation of three genes ( gst , sod , and crt ) and down-regulation of one gene ( mt ) after exposure to individual pesticides and their mixtures. This pointed towards dysregulation of detoxification processes and oxidative damage. Collectively, the study underscored that the widespread application of these two pesticides might pose potential ecotoxicological risks to the soil ecosystem. In essence, these discoveries enriched our insights into the potential hazards linked to the simultaneous use of multiple pesticides in real-world settings. They underscored the significance of taking into account both synergistic effects and employing judicious pesticide management strategies to alleviate ecological impacts.