Transcriptome Sequencing And Virulence Related Genes Analysis Of Haemophilus Parasuis With Different Virulence

Haemophilus parasuis(HPS)is one of the most harmful bacterial infectious diseases,which can lead to systemic inflammatory reactions in pigs and cause irreversible economic losses to the pig industry.HPS is also often combined with other viruses and bacteria to increase the difficulty of disease prevention and treatment.The laboratory began an epidemiological survey of Haemophilus parasuis in major pig farms in Liaoning province from 2015 and found that HPS is one of the most important factors causing piglet morbidity and mortality,especially in autumn and winter.A survey of the prevalence of HPS serotypes found that serum types 4,9 and 13 are the predominant serotypes in Liaoning.In order to understand the pathogenic mechanism of HPS Liaoning strain and to effectively prevent and control the disease,the laboratory-preserved strains YK1603(YingKou isolate,serum type 9 and weakly toxic strain),XM1602(XinMin isolate,serum type 4 and intoxication strain),CY1201(ChaoYang isolate,serum type 13 and virulent strain),the strains and serotypes were verified by Gram staining and 16 SrDNA.Used YK1603 strain as a control.Three different virulence strains were analyzed by transcriptome sequencing.The gene with significant difference was analyzed by GO enrichment analysis,KEGG pathway enrichment analysis and compare analysis with VFDB database.In addition,we carried out ordinary PCR identification of the relevant virulence genes reported in the literature but not detected in transcriptome sequencing.We hope to provide basic data for the pathogenic mechanism of HPS and screening for target genes for vaccine development.The main conclusions of the test are as follows:1.A total of 2107 genes were detected after transcriptome sequencing.There were 195 genes with significant differences between YK1603 and CY1201,of which 71 genes were up-regulated and 124 genes were down-regulated.There were 705 genes with significant differences between YK1603 and XM1602,415 genes were up-regulated,and 290 genes were down-regulated.There was no significant difference in expression of the remaining genes.2.GO function enrichment analysis showed that the differential genes were enriched in 15 functional categories compared with YK1603 and CY1201;differential genes enriched in YK1603 compared to XM1602 in 27 functional categories;suggesting that these functional enrichment may be related to strains virulence.3.In the KEGG pathway enrichment analysis,the differential genes of YK1603 and CY1201 were enriched in 34 pathways,of which 7 pathways were significantly enriched;while the differential genes of YK1603 and XM1602 were enriched in 64 pathways,among which there were One pathway is markedly enriched.4.The comparison between the YK1603 and CY1201,YK1603 and XM1602 differential genes and the VFDB database revealed that 6 differentially expressed genes were YK1603 and CY1201,of which 4 genes were up-regulated,2 genes were down-regulated;18 differential genes between YK1603 and XM1602 were successfully aligned,with 11 genes up-regulated and 7 genes down-regulated.It is speculated that these genes may affect the virulence of strains and are the focus of follow-up studies.5.Thirty virulence-related genes were identified by ordinary PCR and 23 HPS shared genes of three different virulence were found.In addition,the virulence related genes contained in different virulence strains are different,and it is speculated that these differential genes are one of the causes of the different pathogenicity of strains.