邻苯二甲酸二(2-乙基己基)酯对罗非鱼肝脏转录组影响研究

Transcriptome analysis in the liver of Nile tilapia(Oreochromis niloticus) after treated with di(2-ethylhexyl) phthalate

邻苯二甲酸二(2-乙基己基)酯(DEHP)作为生产量和使用量最多的一种邻苯二甲酸酯类化合物,其对水生生物具有多种毒性.本研究选用中国南方地区最重要的经济鱼类尼罗罗非鱼(Oreochromis niloticus)作为实验对象,研究DEHP(50mg/kg bw)作用下罗非鱼肝脏组织内转录组的响应特征.利用IlluminaTM HiSeq 4000测序平台对DEHP处理组和对照组尼罗罗非鱼肝脏RNA样品分别进行转录组测序.对照组和DEHP暴露组分别获得30.10Mb和30.16Mb待分析数据(clean reads),对转录组数据进行组装并去冗余后得到58,585个Unigene.将DEHP处理组和对照组的转录组数据进行比较一共获得5,008个差异表达基因,其中上调表达基因和下调表达基因分别为3,217个和1,791个.通过GO和KEGG功能分析后发现这些差异表达基因主要为机体免疫、生殖内分泌以及脂类代谢相关基因,这表明DEHP对尼罗罗非鱼肝脏毒性主要表现为免疫毒性、生殖毒性和脂类代谢紊乱.另外,实时荧光定量PCR验证结果发现转录组分析数据基本可靠.上述结果为在转录组水平筛选DEHP生物标志物,解析DEHP对罗非鱼毒性作用的分子机制提供了科学参考.

Di-(2-ethylhexyl) phthalate(DEHP) is currently the most frequently detected phthalic acid esters(PAEs) and can induce diverse toxicities on aquatic organisms. To understand the transcriptomic responses of fish exposed to DEHP, we performed transcriptomic profiles in liver of tilapia(Oreochromis niloticus), which is the most important commercial fishes in Guangdong province. Transcriptome sequencing in liver of Nile tilapia exposed to olive oil(control group) and 50 mg kg-1body weight of DEHP for 7days was performed respectively using Illumina HiSeq 4000 platform. A total of 30.10 Mb and 30.16 Mb clean reads were retrieved from the control and DEHP treated libraries, respectively. De-novo assembly of all the clean reads obtained 58,585 unigenes. After comparing the two libraries, 3,217 and 1,791 genes were identified as significantly increased and depressed, respectively. Gene ontology(GO) classification system and Kyoto Encyclopedia of Genes and Genomes(KEGG) database analysis demonstrated that DEHP significantly disturbed the expression level of genes associated with immunity, endocrine and reproductive system, lipid metabolism and so on. Quantitative real-time PCR was performed to validate the results of RNA-sequencing(RNA-seq) analysis. The resulting data provide new insights for exploring the molecular basis of tilapia response to DEHP exposure.