Stereoselective toxicity and metabolic impacts of difenoconazole-alcohol enantiomers in earthworms: Accumulation, degradation, and oxidative stress

The stereoselective effects of difenoconazole-alcohol on soil organisms have not been extensively studied. This research investigates the accumulation, degradation, and oxidative stress induced by difenoconazole-alcohol and its enantiomers in earthworms at exposure levels of 0.5 mg/kg and 5 mg/kg. Transcriptomic and metabolomics analyses were also performed to elucidate the differential toxicity effects of the two enantiomers on earthworms. The results indicate that no significant differences were observed in the accumulation and degradation of difenoconazole-alcohol enantiomers in earthworms. However, biochemical markers associated with reactive oxygen species (ROS), such as SOD, CAT, GST, MDA, and 8-OHdG, exhibited significant stereoselectivity. Transcriptomic analysis revealed that exposure to difenoconazole-alcohol disrupted the expression of genes involved in glutathione metabolism, peroxisomal processes, and oxidative phosphorylation in earthworms. Moreover, the S-(-)-difenoconazole-alcohol enantiomer demonstrated a stronger effect than the R-(+)-enantiomer. Untargeted metabolomics analysis further uncovered differences between the two enantiomers in glutathione, amino acid, and lipid metabolism. Collectively, these findings suggest that chiral difenoconazole-alcohol exerts stereoselective ecological effects on earthworms, with the toxicity order being S-(-)-difenoconazole-alcohol > Rac-difenoconazole-alcohol > R-(+)-difenoconazole-alcohol.