The Study Of Two Outer Membrane Proteins Of Edwardsiella Tarda And Its Subunit Vaccines

Edwardsiella tarda is a vital bacterial pathogen to a wide range of aquaculture animals,causing severe lesions and economic loss.The bacterial outer membrane proteins are important components of bacterial cell.In our study,we focused on two outer membrane proteins of E.tarda.We analyzed and examined the function of two outer membrane proteins of E.tarda(named Omp1_Etand Omp2_Et).The Omp1_Etand Omp2_Et were founded to localize on the surface of E.tarda and were predicted as virulence-related proteins.The recombinant Omp1_Etand Omp2_Et were interacted with the peripheral blood leukocytes of Paralichthys olivaceus.We knockout gene Omp1 or Omp2,and constructed the mutant strains TX01Δomp1 or TX01Δomp2.Compared with the wild type,Omp1 knockout TX01Δomp1 and Omp2 knockout TX01Δomp2 were significantly reduced in motility,biofilm formation,attachment and invasion into host cells and inducing fish mortality.Furthermore,compared with the wild type,TX01Δomp1 was significantly impaired in tissue dissemination.Meanwhile,compared with the wild type,the survival ability of TX01Δomp1 and TX01Δomp2 were significantly reduced under oxidizing conditions while the survival ability of TX01Δomp1 were significantly reduced under low p H.When introduced into flounder as a subunit vaccine,r Omp1_Etand r Omp2_Et subunit vaccines induced strong immune protection against E.tarda challenge.Taken together,our studies indicated that Omp1_Etand Omp2_Etwere surface-located virulence factors and r Omp1_Et can induce effective immune-protection as a subunit vaccine.Our study firstly indicated that Omp1_Etand Omp2_Et were surface-located virulence factors,and constructed Omp1_Etand Omp2_Etsubunit vaccines could induce effective immune-protection to Paralichthys olivaceus from infection of E.tarda.