LAUSR

Kresoxim-methyl (KM) is a broad spectrum strobilurin fungicide that has been used widely on crops around the world. In the present study, we aimed to investigate the toxic effects of KM using various sublethal endpoints during zebrafish (Danio rerio) larval development. Results showed that the LC50 values of KM to zebrafish at multiple life stages (embryo, larvae, juvenile and adult) were 0.340, 0.224, 0.328 and 0.436 mg/L, respectively. The transcription patterns of 45 genes involved in hypothalamic-pituitary-thyroid/gonadal (HPT/HPG) axis, oxidative stress and apoptosis revealed KM could affect zebrafish larval development at multiple pathways. The activities of aromatase, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), caspase 3 (Cas3) and caspase 9 (Cas9), and the levels of estradiol (E2), vitellogenin (VTG), thyroid hormones (T3 and T4), reactive oxygen species (ROS) and ATP after embryos exposed to KM for 3 d, 6 d and 10 d were correlated well with the transcription of the corresponding molecules involved in these pathways. In addition to providing the first description of the toxic effects induced by KM during larval development, the results of present study also provided the potential mechanisms of KM on multi-level biomarker responses in larval zebrafish.