Selection and Characterization of Phage-Resistant Mutant Strains of Listeria monocytogenes Reveal Host Genes Linked to Phage Adsorption
Selection and Characterization of Phage-Resistant Mutant Strains of Listeria monocytogenes Reveal Host Genes Linked to Phage Adsorption
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DOI：
10.1128/aem.00087-15
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发表时间：
2015-07-01
影响因子：
4.4
通讯作者：
Wiedmann, Martin
中科院分区：
文献类型：
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作者：
Denes, Thomas;den Bakker, Henk C.;Wiedmann, Martin
感染李斯特菌的噬菌体很容易从含有李斯特菌的环境中分离出来，但人们对它们对宿主施加的选择力知之甚少。在这里，我们发现两种强毒噬菌体 LP-048 和 LP-125 通过不同的机制吸附到单核细胞增生李斯特氏菌菌株 10403S 的表面。我们使用全基因组测序分离并测序了 69 个对一种或两种噬菌体具有抗性的 10403S 自发突变株。 56 个噬菌体抗性突变株的突变只有一个突变，映射到代表 10403S 染色体上 5 个基因座的 10 个基因。另外12个突变株显示出2个突变，1个突变株显示出3个突变。其中两个基因座包含七个基因，积累了大部分突变（n = 64）。 10 个基因中每一个的代表性突变菌株都显示出通过吸附抑制机制抵抗噬菌体感染。突变菌株与相关野生型等位基因的互补能够挽救 10 个代表性突变菌株中 6 个的噬菌体敏感性。麦芽凝集素与 N-乙酰氨基葡萄糖特异性结合，与 10403S 和耐 LP-048 的突变株结合，但不与仅耐 LP-125 的突变株结合。我们得出的结论是，仅对 LP-125 具有抗性的突变菌株在其壁磷壁酸 (WTA) 中缺乏末端 N-乙酰氨基葡萄糖，而对两种噬菌体具有抗性的突变菌株在其鼠李糖生物合成操纵子中具有破坏性突变，但在其 WTA 中仍具有 N-乙酰氨基葡萄糖。
Listeria-infecting phages are readily isolated from Listeria-containing environments, yet little is known about the selective forces they exert on their host. Here, we identified that two virulent phages, LP-048 and LP-125, adsorb to the surface of Listeria monocytogenes strain 10403S through different mechanisms. We isolated and sequenced, using whole-genome sequencing, 69 spontaneous mutant strains of 10403S that were resistant to either one or both phages. Mutations from 56 phage-resistant mutant strains with only a single mutation mapped to 10 genes representing five loci on the 10403S chromosome. An additional 12 mutant strains showed two mutations, and one mutant strain showed three mutations. Two of the loci, containing seven of the genes, accumulated the majority (n = 64) of the mutations. A representative mutant strain for each of the 10 genes was shown to resist phage infection through mechanisms of adsorption inhibition. Complementation of mutant strains with the associated wild-type allele was able to rescue phage susceptibility for 6 out of the 10 representative mutant strains. Wheat germ agglutinin, which specifically binds to N-acetylglucosamine, bound to 10403S and mutant strains resistant to LP-048 but did not bind to mutant strains resistant to only LP-125. We conclude that mutant strains resistant to only LP-125 lack terminal N-acetylglucosamine in their wall teichoic acid (WTA), whereas mutant strains resistant to both phages have disruptive mutations in their rhamnose biosynthesis operon but still possess N-acetylglucosamine in their WTA.