Enantioselective toxicity of a chiral fungicide: Mefentrifluconazole reprograms energy metabolism in Eisenia fetida

Widespread use of the novel chiral triazole fungicide mefentrifluconazole (MFZ) poses a threat to soil ecological health. While previous studies have implicated energy supply disruption as a key mechanism underlying MFZ-induced toxicity in earthworms ( Eisenia fetida ), the precise effects of MFZ enantiomers on energy metabolism remain unclear. Here, we utilized transcriptomics, targeted energy metabolomics, and bioenergetic indicators to investigate the impact of 4 mg/kg R-(-)-MFZ and S-(+)-MFZ soil exposure on E. fetida energy metabolism. Based on the previous finding that MFZ enantiomers inhibit oxidative phosphorylation (OXPHOS), further analyses showed that the TCA cycle is dysfunctional, characterized by reduced activities of the key enzymes isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. In response to energetic stress, metabolic reprogramming of OXPHOS to glycolysis transition was observed for the first time from E. fetida , as evidenced by elevated levels of key glycolytic intermediates and increased phosphofructokinase activity. Additionally, MFZ enantiomers induced enhanced fatty acid β-oxidation by increasing carnitine palmitoyltransferase transcript levels and enzyme activity. Notably, S-(+)-MFZ exhibited a more pronounced effect on these parameters, highlighting its greater toxicity. These findings provide compelling evidence that MFZ enantiomers reprogram energy metabolism in E. fetida . The enantioselective nature of these effects underscores the necessity of incorporating chiral isomer considerations into ecological risk assessments to comprehensively evaluate potential health risks to ecosystems.