Cheng Changyong, Wang Hang, Ma Tiantian, Han Xiao, Yang Yongchun, Sun Jing, Chen Zhongwei, Yu Huifei, Hang Yi, Liu Fengdan, Fang Weihuan, Jiang Lingli, Cai Chang, Song Houhui
China-Australian Joint Laboratory for Animal Health Big Data Analytics, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection and Internet Technology, College of Animal Science and Technology, Zhejiang A&F University, Lin'an, China.
Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, China.
Front Microbiol. 2018 Feb 13;9:208. doi: 10.3389/fmicb.2018.00208. eCollection 2018.
is a food-associated bacterium that is responsible for food-related illnesses worldwide. In the EGD-e genome, FlhB, FliM, and FliY by , and , respectively) are annotated as putative flagella biosynthesis factors, but their functions remain unknown. To explore whether FlhB, FliM, and FliY are involved in flagella synthesis, we constructed , and other flagellar-related gene deletion mutants using a homologous recombination strategy. Then, we analyzed the motility, flagella synthesis, and protein expression of these mutant strains. Motility and flagella synthesis were completely abolished in the absence of , or . These impaired phenotypes were fully restored in the complemented strains CΔ, CΔ, and CΔ. The transcriptional levels of flagellar-related genes, including , and , were downregulated markedly in the absence of , or . Deletion of resulted in the complete abolishment of FlaA expression, while it decreased FliM and FliY expression. The expression of FlaA was abolished completely in the absence of or . No significant changes were found in the expression of FlhF and two flagella synthesis regulatory factors, MogR and GmaR. We demonstrate for the first time that FlhB, FliM, and FliY not only mediate motility, but also are involved in regulating flagella synthesis. This study provides novel insights that increase our understanding of the roles played by FlhB, FliM, and FliY in the flagellar type III secretion system in .
是一种与食物相关的细菌，在全球范围内导致与食物相关的疾病。在EGD - e基因组中，FlhB、FliM和FliY（分别由 、 和 注释）被注释为假定的鞭毛生物合成因子，但其功能仍不清楚。为了探究FlhB、FliM和FliY是否参与鞭毛合成，我们使用同源重组策略构建了 以及其他鞭毛相关基因缺失突变体。然后，我们分析了这些突变菌株的运动性、鞭毛合成和蛋白质表达。在缺失 、 或 时，运动性和鞭毛合成完全丧失。在互补菌株CΔ、CΔ和CΔ中，这些受损表型完全恢复。在缺失 、 或 时，包括 、 和 在内的鞭毛相关基因的转录水平显著下调。缺失 导致FlaA表达完全丧失，同时降低了FliM和FliY的表达。在缺失 或 时，FlaA的表达完全被消除。FlhF以及两个鞭毛合成调节因子MogR和GmaR的表达未发现显著变化。我们首次证明FlhB、FliM和FliY不仅介导 运动性，还参与调节鞭毛合成。这项研究提供了新的见解，增进了我们对FlhB、FliM和FliY在 的鞭毛III型分泌系统中所起作用的理解。
