Introducing a Novel, Broad Host Range Temperate Phage Family Infecting Rhizobium leguminosarum and Beyond.
Introducing a Novel, Broad Host Range Temperate Phage Family Infecting Rhizobium leguminosarum and Beyond.
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DOI：
10.3389/fmicb.2021.765271
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发表时间：
2021
影响因子：
5.2
通讯作者：
Harrison E
中科院分区：
文献类型：
--
作者：
Ford S;Moeskjær S;Young P;Santamaría RI;Harrison E
温带噬菌体在细菌群落中发挥着重要作用，但在很大程度上被忽视了，特别是在非致病细菌中。在根瘤菌中，温带噬菌体的存在有可能对生态产生重大影响，但很少有例子被描述。在这里，我们描述了一组新的5个豆科根瘤菌前驱体，能够在其宿主属内的广泛宿主范围内维持感染。基因组比较发现了更多可能感染全球分离的多种根瘤菌的前驱噬菌体，揭示了一个由10个温带噬菌体组成的更广泛的家族，其中包括先前描述的一个裂解噬菌体RHEph01，它似乎已经失去了形成溶原菌的能力。原噬菌体和寄主系统发育之间的系统发育不一致表明根瘤菌谱系之间存在着积极动员的历史。基因组比较显示，除了大约5kb的高度变异性区域外，基因内容和序列都是保守的，几乎完全包含假设基因。此外，在整个基因组中存在几个水平获得的基因，包括一个假定的只存在于RHEph01基因组中的抗阻遏子，这可能解释了它明显不能形成溶原物。综上所述，这组噬菌体成员之间的表型和基因组比较揭示了一个病毒分支，它们在根瘤菌种内和根瘤菌之间具有长期的动员历史。
Temperate phages play important roles in bacterial communities but have been largely overlooked, particularly in non-pathogenic bacteria. In rhizobia the presence of temperate phages has the potential to have significant ecological impacts but few examples have been described. Here we characterize a novel group of 5 Rhizobium leguminosarum prophages, capable of sustaining infections across a broad host range within their host genus. Genome comparisons identified further putative prophages infecting multiple Rhizobium species isolated globally, revealing a wider family of 10 temperate phages including one previously described lytic phage, RHEph01, which appears to have lost the ability to form lysogens. Phylogenetic discordance between prophage and host phylogenies suggests a history of active mobilization between Rhizobium lineages. Genome comparisons revealed conservation of gene content and order, with the notable exception of an approximately 5 kb region of hypervariability, containing almost exclusively hypothetical genes. Additionally, several horizontally acquired genes are present across the group, including a putative antirepressor present only in the RHEph01 genome, which may explain its apparent inability to form lysogens. In summary, both phenotypic and genomic comparisons between members of this group of phages reveals a clade of viruses with a long history of mobilization within and between Rhizobium species.