High-throughput Screening Of Small Molecule Compounds Induced By The T3SS Of Xanthomonas Campestris Pathovar Campestris

Most of gram negative pathogens inject the virulence protein to host cells by type III secretion system(T3SS)of in the body leading to the host pathogenicity.In Xcc 8004,the virulence proteins called type III effectorstransferedinto host cellsby type III secretion system(T3SS genes),causing black rot disease in host plant pathogenic and HR in non host plants.Our laboratory has constructed a report strain 8004/pLux0241 containing the bacterial luciferase gene(luxAB)and the effector gene promoter of XC0241,on the basis of high-throughput screening of small molecule compounds from a total of 17082 small molecule compounds which from the National Resource Center for the public platform of small molecular libraries,and medium of XZM,order to find some small molecule compounds indured Xcc 8004 T3SS.It will help us develop new lead compounds,new target and provide the basis of biological chemistry and molecular mechanism of important for the establishment of new strategy.In this study,the reported strain 8004/pLux0241 cultured on XZM which added todifferent small molecule compounds.After culturing sometime,the medium of Lux tesed by Synergy H1 full function microplate.The results show that,the XZM medium of Lux value which supplemented with final concentration 30 ?M Splitomycin and SB204741 small molecular compounds was significantly higher than the control group DMSO(small molecule compounds stored in DMSO);At the same time,the Lux value of XVM2,XCM1 which added to splitomycin and SB204741 small molecular compounds is higher than the control group DMSO,and does not affect cell growth.In order to further verify the effects of Splitomycin and SB204741 on Xcc 8004 type ? secretion system.We were detected the effect through GUS reporting system.The results show that the GUS values were was also significantly higher than DMSO in XZM,XVM2 which added to Splitomycin and SB204741.Using RT-PCR and qRT-PCR method,as a reference gene correction to 16S rRNA,to know whether the transcription level of T3SS genespecific induced by the Splitomycin and SB204741.It is found that the relative transcription level of XC0241?hrpX gene with Splitomycin and SB204741 of small molecular compounds increased,while no significant changes in the transcription level of XC1638(T4SS)?XC0749(T2SS)gene.However the transcription level of hrpG is decreased.For detection of biocontrol by spray method and pressure infiltration method,we found that the Splitomycin and SB204741 affect Xcc 8004 pathogenic on host carrots,but HR not found in advance or delay.