Riemerella anatipestifer causes epizootic infectious disease in ducks, geese, turkeys and other birds, and serious economic losses especially to the duck industry. However, little is known about the molecular basis of its pathogenesis. In this study, signature-tagged transposon mutagenesis based on Tn4351 was developed in R. anatipestifer to identify genes essential for survival and pathogenesis. Seventeen tagged Tn4351 random mutation libraries of the R. anatipestifer strain WJ4 containing 5100 mutants were screened for survive using a duckling infection model. Twenty mutants that could not be recovered from the infected ducklings, were identified, and 17 mutated genes were identified by inverse PCR or genome-walking PCR. Of these genes, FIP52_03215, FIP52_04350 and FIP52_09345, were inserted into two mutant strains, and FIP52_03215 and FIP52_03175 were found exclusively on the chromosome of serotype 1 R. anatipestifer strains. Twelve out of 17 genes encoding for proteins were predicted to be involved in amino acid, nucleotide, coenzyme, or lipid transport and metabolism, one gene was predicted to be involved in signal transduction, one gene was predicted to be involved in DNA replication, recombination and repair, the other three genes had an unknown function. Animal experiments showed that the virulence of mutants 16-284, 7-295, 24-231, 9-232 and 19-214 were significantly attenuated compared to that of the wild-type WJ4. Moreover, the median lethal dose of mutant 16-284 was greater than 10¹⁰ CFU, and its virulence to ducklings was partially restored when it was complemented with the shuttle expression plasmid pRES-FIP52_09345. The results in this study will be helpful to further study the molecular mechanisms of the pathogenesis of R. anatipestifer infection.

厌食利默氏菌在鸭，鹅，火鸡和其他鸟类中引起流行性传染病，并给经济造成重大损失，特别是对鸭业而言。但是，对其发病机理的分子基础知之甚少。在这项研究中，在R. anatipestifer中开发了基于Tn4351的带标签标签的转座子诱变，以鉴定生存和发病机理必不可少的基因。十七标记了的Tn4351随机突变库R.疫使用小鸭感染模型筛选了含有5100个突变体的WJ4菌株生存期。鉴定了20个不能从被感染的小鸭中回收的突变体，并通过反向PCR或基因组步行PCR鉴定了17个突变基因。在这些基因中，将FIP52_03215，FIP52_04350和FIP52_09345插入两个突变株中，并且仅在血清型1 R. anatipestifer的染色体上发现了FIP52_03215和FIP52_03175 。株。编码蛋白质的17个基因中有12个被预测与氨基酸，核苷酸，辅酶或脂质转运和代谢有关，一个基因被预测与信号转导有关，一个基因被预测与DNA复制，重组有关。和修复，其他三个基因的功能未知。动物实验表明，与野生型WJ4相比，突变体16-284、7-295、24-231、9-232和19-214的毒力显着减弱。此外，突变体16-284的中位致死剂量大于10 ¹⁰当它与穿梭表达质粒pRES-FIP52_09345互补时，CFU及其对小鸭的毒性部分恢复。这项研究的结果将有助于进一步研究厌食R. anatipestifer感染的分子机制。