Analysis of the stereoselective fate and toxicity of penflufen in the water-sediment system for risk reduction

Chiral succinate dehydrogenase inhibitor (SDHI) fungicides are widely used in agricultural production, but there is insufficient research on their environmental risk in water–sediment ecosystems. Here, the stereoselective fate and toxic effects of the chiral SDHI fungicide, penflufen, in the water–sediment system were investigated. The results showed that S-penflufen is more persistent in water, sediment, and zebrafish. Additionally, the sorption coefficient (Koc) in sediment and uptake rate constant (Ku) in zebrafish of S-penflufen were higher than those of R-penflufen. The acute toxicity of S-penflufen to zebrafish, Daphnia magna and Chironomus kiiensis were 32-, 6.1-, and 8.9-fold higher than those of R-penflufen. The AlphaFold2 and molecular docking results showed that S-penflufen had stronger binding capability with SDH in the three water–sediment organisms than R-penflufen. Therefore, S-penflufen induced stronger sub-chronic toxic effects on zebrafish than R-penflufen, even at 0.05 mg/L. The results of multi-omics analysis showed that S-penflufen affected the tricarboxylic acid cycle in zebrafish and induced antioxidant, detoxification, and immune system responses, ultimately affecting zebrafish metabolic processes and cellular function. The overall results indicate that S-penflufen has a higher risk in water–sediment systems. Moreover, combining multi-omics and AlphaFold2 techniques facilitates the elucidation of the molecular mechanism of the stereoselective toxic effects of chiral pesticides.