Transcriptomic profile in carbendazim-induced developmental defects in zebrafish (Danio rerio) embryos/larvae.

Carbendazim is a widely used fungicide to protect agricultural and horticultural crops against a wide array of fungal species. Published reports have shown that the wide usage of carbendazim resulted in reprotoxicity, carcinogenicity, immunotoxicity, and developmental toxicity in mammalian models. However, studies related to the developmental toxicity of carbendazim in aquatic organisms are not clear. To address this gap, an attempt was made by exposing zebrafish embryos to carbendazim (800 μg/L) and assessing the phenotypic and transcriptomic profile at different developmental stages [24 hour post fertilization (hpf), 48 hpf, 72 hpf and 96 hpf). At 48 hpf, phenotypic abnormalities such as delay in hatching rate, deformed spinal axial curvature, and pericardial edema were observed in zebrafish larvae over its respective controls. At 72 hpf, exposure of zebrafish embryos exposed to carbendazim resulted in scoliosis; however, unexposed larvae did not exhibit signs of scoliosis. Interestingly, the transcriptomic analysis revealed a total of 1253 DEGs were observed at selected time points, while unique genes at 24 hpf, 48 hpf, 72 hpf and 96 hpf was found to be 76.54 %, 61.14 %, 92.98 %, and 68.28 %, respectively. Functional profiling of downregulated genes revealed altered transcriptomic markers associated with phototransduction (24 hpf and 72 hpf), immune system (48 hpf), and SNARE interactions in the vesicular pathway (96 hpf). Whereas functional profiling of upregulated genes revealed altered transcriptomic markers associated with riboflavin metabolism (24 hpf), basal transcription factors (48 hpf), insulin signaling pathway (72 hpf), and primary bile acid biosynthesis (96 hpf). Taken together, carbendazim-induced developmental toxicity could be ascribed to pleiotropic responses at the molecular level, which in turn might reflect phenotypic abnormalities.