Function Of A ABC Transporter Gene In Theprocess Of Pseudomonas Plecoglossicida Infection By Aquatic Pathogenic Bacteria

Pseudomonas plecoglossicida is a common bacterium in the natural environment and is a relatively common pathogenic bacteria in aquaculture.During the breeding period,the disease caused by P.plecoglossicida was almost accompanied by all stages of fish growth.The incidence of this disease was faster and the onset time was larger.ATP Binding Cassette(ABC)transporters comprise a large superfamily of membrane proteins.From bacteria to man,they transport molecules through the permeability barriers of cell membranes.Cargo molecules are extremely diverse,ranging from ions,small to medium molecules(sugars,amino acids,lipids,ionic metals)to large compounds(peptides,proteins,organometal complexes,and antibiotics).They are involved in many important physiological processes such as nutrient import,cellular detoxification,lipid homeostasis,signal transduction,antiviral defense,and antigen presentation.In this paper,a ABC transporter gene in P.plecoglossicida was stably silenced,and then a series of follow-up experiments were conducted to explore the function of the gene in the process of infecting Epinephelus coioides with P.plecoglossicida.At first,the silencing strain were constructed at five different targets of the ABC transporter gene,and the silencing efficiency was detected by real time quantitative PCR.The strain with the best silencing efficiency was selected and tested through a live infection experiment.The mortality of the silencing strain was found to be reduced.The result showed that the genes do play a role in the pathogenicity of P.plecoglossicida.After infected by the silence and the wild strain,a followup observation of the various tissues in E.coioides found that in the most obvious symptoms of spleen tissue,silent strain of the disease was significantly weakened,what once again proved that the ABC transporter gene played a significant role in the pathogenicity of P.plecoglossicida.The growth curve showed that the growth rate of the silence strain and the wild strain was slightly different in vitro culture conditions of the laboratory,but the difference was not significant,and the overall trend was the same.It can be considered that the silence of the ABC transporter gene had no significant effect on the growth of P.plecoglossicida.Through the study of spatio-temporal expression,it was found that in the process of infecting the E.coioides,the bacteria began to proliferate from 36 h and reached the peak at 48 h.In this study,the spleen of P.plecoglossicida post infected 48 hours was selected for transcriptome sequencing.The analysis of the large number of transcriptome data obtained revealed that,A large number of differential genes of pathogen are concentrated in the metabolism process,proving that the ABC transporter gene does have the function of transferring various substances in P.plecoglossicida;For the host,a large number of differential genes are concentrated in the signal transduction and immune system.Which proves that the host has a strong immune response after the pathogen infects the host.In this way,we study the expression of P.plecoglossicida in the host and provide a reference for explaining its pathogenesis.