猪源大肠杆菌O157∶H7毒力差异株的转录组测序分析

Transcriptome Sequencing Analysis of E.coli O157∶H7 Strains of Different Virulence from Pigs

为了解大肠杆菌O157∶H7毒力差异株转录组差异,丰富O157∶H7转录组数据信息,本研究采用Illumina HiSeqTM2000平台对两株大肠杆菌O157∶H7毒力差异株进行高通量测序,测序数据采用测序评估、基因功能注释等生物信息学方法进行分析。结果发现,经过测序,两个菌株分别获得3 113 118和2 944 912条reads,比对到参考基因组上的reads分别占总reads的83.76%和78.97%。以中等毒力株为参考,在高毒力株中共获得941个差异表达基因,其中上调基因637个,下调基因304个。GO功能注释分析表明,差异表达基因主要与催化活性功能、黏附、转运活性、受体活性、酶调节活性、定位、生化调节、运动等诸多生理生化过程相关;KEGG富集分析发现共有425个基因注释到160个代谢通路中,其中新陈代谢、核糖体、鞭毛合成、嘧啶代谢、糖类代谢、细菌趋化等通路显著富集。此次通过大肠杆菌O157∶H7毒力差异株转录组研究对差异表达基因涉及的信号调控及可能的功能基因进行了探索,丰富了转录组信息,为进一步开展大肠杆菌O157∶H7毒力相关基因的研究及分子调控机制奠定了基础。

In order to gain an insight of the transcriptomes difference in E.coli O157：H7 strains of different virulence,enrich the E.coli O157：H7 transcriptome data,two E.coli O157：H7 strains of different virulence were selected,then the transcriptome libraries of the strains were constructed using Illumina HiSeqTM 2000 sequencing technique.The bioinformatics methods were used subsequently,such as sequencing assess and gene function annotation. The results showed that 3 113 118 reads were obtained in the high virulence strain,and 2 944 912 reads were obtained in normal virulence strain.83.76% and 78.97% reads could be compared to the E.coli O157：H7 reference genome sequence,respectively. Comparison with the transcriptome of normal virulence strain,941 differentially expressed genes were found in the high virulence strain,including 637 up-regulated genes and 304 down-regulated genes.GO function annotation classifications indicated that the differentially expressed genes were divided into different function categories,in which many functional categories were mainly involved,such as catalytic activity,binding,transporter activity,receptor activity,enzyme regulator activity,localization,biological regulation,locomotion. KEGG analysis showed 425 genes were annotated to 160 metabolic pathways. Metabolic,ribosome,flagellar assembly,pyrimidine metabolism,starch and sucrose metabolism,bacterial chemotaxis pathways were significantly enriched. The transcriptome study of E.coli O157：H7 strains of different virulence using high-throughput sequencing technology revealed the number of differentially expressed genes in different virulence,obtained the function,classification and metabolic pathway of differentially expressed genes,which enriched the transcriptome information of E.coli O157：H7,and laid a foundation for the study on related genes with virulence traits and molecular mechanisms in E.coli O157：H7.