Zhang Yue, Xian Honghong, Jiang Xi, Yuan Yu, Ji Ruoyun, Jiao Xinan, Li Qiuchun
Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, China; Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China.
Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, China.
Microbiol Res. 2022 Sep;262:127085. doi: 10.1016/j.micres.2022.127085. Epub 2022 Jun 6.
The type VI secretion system (T6SS) encoded by Salmonella Pathogenicity Island 19 (SPI-19) has been confirmed to be involved in bacterial infection or colonization in hosts and in the inhibition of the host T-cell immune response. However, deletion of the core genes (clpV, vgrG, and hcp2) encoding the T6SS apparatus does not affect the phenotypes caused by SPI-19-encoded T6SS. As Salmonella infection in host cells and survival in chickens are closely associated with the type III secretion system (T3SS), RNA-Seq was performed, and the results revealed that most T3SS genes were downregulated in the C79-13ΔSPI-19 mutant. To identify the SPI-19 genes involved in regulating T3SS genes expression, we constructed mutants of genes encoding potential regulators (RS09140 and RS09275) or proteins with Sel1-like motifs (RS09150 and RS09155) and analyzed their associated phenotypes. Deletion of RS09150 and RS09155 caused the decreased bacterial infection in avian cells and bacterial colonization in chicken organs. In addition, qRT-PCR results revealed that both mutants showed decreased expression levels of regulatory genes of T3SS. The present findings demonstrate that the two Sel1-like proteins RS09150 and RS09155 in S. Pullorum SPI-19 contribute to bacterial infection in chickens by mediating the expression of T3SS genes, indicating a potential crosstalk between SPI-19 and T3SS in Salmonella.
由沙门氏菌致病岛19（SPI-19）编码的VI型分泌系统（T6SS）已被证实参与宿主中的细菌感染或定植以及对宿主T细胞免疫反应的抑制。然而，编码T6SS装置的核心基因（clpV、vgrG和hcp2）的缺失并不影响由SPI-19编码的T6SS引起的表型。由于宿主细胞中的沙门氏菌感染和鸡体内的存活与III型分泌系统（T3SS）密切相关，因此进行了RNA测序，结果显示在C79-13ΔSPI-19突变体中大多数T3SS基因表达下调。为了鉴定参与调节T3SS基因表达的SPI-19基因，我们构建了编码潜在调节因子（RS09140和RS09275）或具有Sel1样基序的蛋白质（RS09150和RS09155）的基因突变体，并分析了它们的相关表型。缺失RS09150和RS09155导致禽细胞中细菌感染减少以及鸡器官中细菌定植减少。此外，qRT-PCR结果显示两个突变体中T3SS调节基因的表达水平均降低。目前的研究结果表明，鸡白痢沙门氏菌SPI-19中的两种Sel1样蛋白RS09150和RS09155通过介导T3SS基因的表达促进鸡的细菌感染，表明沙门氏菌中SPI-19和T3SS之间存在潜在的相互作用。
