基于转录组学探究除虫脲暴露对鲤肝脏基因表达的影响

Effect of diflubenzuron exposure on gene expression in Cyprinus carpio liver based on transcriptomics

关键词:  鲤  除虫脲  肝脏  转录组学  毒理

Key words:  Carp Cyprinus carpio  Diflubenzuron  Liver  Transcriptomics  Toxicology

摘要:

除虫脲(diflubenzuron, DFB)是一种常用的杀虫剂，其代谢物残留会威胁水生动物及人体健康。为探究水产动物响应DFB胁迫的分子机制，本研究以鲤(Cyprinus carpio)为对象，选定0.1 mg/L和1.0 mg/L的药浴浓度对鲤进行15 d暴露实验。采用RNA-Seq技术对肝脏开展转录组测序，以Padj<0.05和|log2Fold Change|≥1为标准筛选差异表达基因(DEGs)进行GO功能注释和KEGG富集分析等生物信息学分析。结果显示，0.1 mg/L暴露浓度下有2 406个DEGs发生显著变化，1.0 mg/L暴露浓度下有2 688个DEGs发生显著变化，2组共表达的DEGs有821个。GO分析结果显示，DFB暴露组DEGs富集在生物过程、细胞组成和分子功能上。KEGG富集分析显示，低浓度DFB暴露组DEGs显著富集到异生物质的生物降解和代谢、脂质代谢、碳水化合物代谢、氨基酸代谢、信号分子与相互作用、内分泌系统、免疫系统等代谢通路；高浓度DFB暴露组DEGs除了富集到上述代谢通路外，还显著富集到折叠、分类和降解、运输和分解代谢等代谢通路。结果表明，DFB暴露对鲤造成异生物质的生物降解和代谢、脂质代谢、碳水化合物代谢、氨基酸代谢紊乱，并产生内质网应激、炎症反应和免疫毒性。本研究从转录层面上解析了DFB暴露对鲤毒性作用的分子机制，为DFB在水产领域的限量标准制定和环境安全评价提供基础数据。

Abstract:

As a benzoylurea insecticide, diflubenzuron (DFB) has been widely used in the prevention and control of diseases and insect pests in vegetables, fruits, grain cultivation, and other fields in recent years. In addition, because of its low acute toxicity, excellent biological activity, and specific action mechanism, DFB has been widely used in aquaculture to kill bacteria and lice. With its large-scale production and widespread use, its partial residue remains in environmental media, such as water, soil, and the atmosphere, and causes direct or indirect chronic toxicity to aquatic organisms. The residual DFB enters the human body along the food chain and poses a threat to human health when it reaches a certain concentration through chronic exposure and long-term accumulation. At present, research on DFB insecticides has been limited to the usage and dosage, residual metabolism, and its toxicological effects on the environment. There have been no reports, to our knowledge, on the effect of DFB on gene expression in carp liver in China. The purpose of this study was to explore the differential expression of genes in carp liver under DFB stress. In this study, carp (Cyprinus carpio) was selected as the research subject, and three exposure experiments for 15 days under 0.1 and 1.0 mg/L medicated bath concentrations were carried out in parallel for each concentration. High-throughput sequencing of the liver was performed using the Illumina NovaSeq 6000. Differentially expressed genes (DEGs) were screened by Padj < 0.05 and |log2FoldChange| ≥1, and bioinformatics analysis, such as Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, were performed. The transcriptome analysis results showed that 2 406 and 2 688 DEGs changed significantly at 0.1 and 1.0 mg/L exposure concentrations, respectively, and 821 DEGs were co-expressed between the two groups. GO analysis results showed that DEGs in the DFB exposure group were enriched in biological processes, cell compositions, and molecular functions. KEGG enrichment analysis showed that DEGs in the low DFB concentration exposure group were significantly enriched in metabolic pathways, such as biodegradation and metabolism of xenobiotics, lipid metabolism, carbohydrate metabolism, amino acid metabolism, signal molecules and interactions, endocrine system, and immune system. In addition to the above metabolic pathways, DEGs in the high DFB concentration exposure group were significantly enriched in metabolic pathways, such as folding, classification and degradation, transport, and catabolism. Studies have shown that DFB exposure causes the biodegradation and metabolism of xenobiotics, lipid metabolism, carbohydrate metabolism, and amino acid metabolism, and generates endoplasmic reticulum stress, inflammatory response, and immune toxicity. In summary, the results of this study provide basic data and a theoretical basis for further research on the molecular mechanism of DFB stress in carp.