Enantioselective toxic effects of the novel chiral antifungal agrochemical penthiopyrad in the early life stage of zebrafish (Danio rerio).

Penthiopyrad was extensively applied in agricultural production, however, the toxicities information of the penthiopyrad enantiomers on early life stages of aquatic organism were limited. This study investigated the enantioselective toxicity of penthiopyrad on the early life stage of zebrafish by acute toxicity, sublethal toxic effects and the mRNA relative expression levels of genes related to succinate dehydrogenase, cardiac development, and lipid metabolism. The results showed that the 96-h-LC of penthiopyrad racemate and enantiomers to zebrafish embryos were Rac-: 2.784 mg/L; R-(-)-: 3.528 mg/L; S-(+)-: 1.882 mg/L. Penthiopyrad exposure induced autonomous movement abnormalities, slowed heart rate and delayed hatching in zebrafish embryos, and caused developmental toxic effects such as pericardial edema and yolk sac edema. The mRNA relative expression levels results showed that penthiopyrad exposure induced significant enantioselectivity effect for the expression of the Sdha, Pr1 and Nkx2.5 with a 1.94-4.98-fold difference between different enantiomers, and significantly affected succinate dehydrogenase (energy metabolism), lipid metabolism and cardiac development-related genes expression. In general, S-(+)-penthiopyrad induced higher toxic effects in zebrafish embryos, and mitochondrial dysfunction may be an important cause of abnormal development. This study contributed to improve the comprehensive risk assessment and enantiomeric research system of penthiopyrad to early life stage of zebrafish.