Enantioselective Toxic Effects of Prothioconazole toward Scenedesmus obliquus

Prothioconazole (PTC) is a broad-spectrum triazole fungicide with one asymmetric center and consists of two enantiomers, R-(-)-PTC and S-(+)-PTC. To address the concern of its environmental safety, the enantioselective toxic effects of PTC on Scendesmus obliquus (S. obliquus) were investigated. PTC racemates (Rac-PTC) and enantiomers exhibited dose-dependent acute toxicity effects against S. obliquus at a concentration from 1 to 10 mg & BULL;L-1. The 72 h-EC50 value of Rac-, R-(-)-, and S-(+)-PTC is 8.15, 16.53, and 7.85 mg & BULL;L-1, respectively. The growth ratios and photosynthetic pigment contents of the R-(-)-PTC treatment groups were higher than the Rac- and S-(+)-PTC treatment groups. Both catalase (CAT) activities and esterase activities were inhibited in the Rac- and S-(+)-PTC treatment groups at high concentrations of 5 and 10 mg & BULL;L-1, and the levels of malondialdehyde (MDA) were elevated, which exceeded the levels in algal cells for the R-(-)-PTC treatment groups. PTC could disrupt the cell morphology of S. obliquus and induce cell membrane damage, following the order of S-(+)-PTC & AP; Rac-PTC > R-(-)-PTC. The enantioselective toxic effects of PTC on S. obliquus provide essential information for its ecological risk assessment.

Automated summary

The enantioselective toxic effects of Prothioconazole (PTC) on Scendesmus obliquus (S. obliquus) were investigated. It was found that R-(-)-PTC had less impact on the growth and photosynthetic pigment contents of S. obliquus compared to Rac-PTC and S-(+)-PTC. This study provides important information for the ecological risk assessment of PTC.