Enzymatic activity and gene expression changes in the earthworms induced by co-exposure to beta-cypermethrin and triadimefon

Pesticides often exist as complex mixtures in soil environments, yet the toxicity of these combinations has not been thoroughly investigated. In light of this, the current study aimed to assess the enzymatic activity and gene expression responses in the earthworm Eisenia fetida when exposed to a mixture of beta-cypermethrin (BCY) and triadimefon (TRI). The findings revealed that co-exposure to BCY and TRI triggered acute synergistic toxicity in E. fetida, emphasizing the potential risk they pose to soil health. Significant elevations in MDA, Cu/Zn-SOD, and CAT levels were observed across most individual and combined treatments. Additionally, the expression of crt was notably upregulated under most exposure conditions, while the expression levels of tctp and sod were significantly downregulated. These changes suggested the occurrence of oxidative stress and potential carcinogenic effects upon exposure to BCY, TRI, and their combination. Notably, the activities of CAT, caspase-9, and CarE, along with the transcriptional levels of mt, displayed more pronounced variations in response to the pesticide mixture compared to individual exposures. These results indicated that the combined exposure to BCY and TRI intensified oxidative stress, promoted cellular apoptosis, and disrupted detoxification processes more than exposure to either chemical alone. Molecular docking results showed that these two pesticides could interact with CAT, SOD, and GST. These data provided critical insights into the biochemical and molecular toxicity caused by BCY and TRI on E. fetida, offering a deeper understanding of the ecological risks posed by chemical mixtures to soil organisms. This study shed light on the toxicological implications of BCY and TRI co-occurrence and underscored the importance of evaluating the environmental impact of pesticide mixtures to safeguard soil ecosystems.