Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires' disease
Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires' disease
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DOI：
10.1186/s13059-014-0505-0
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发表时间：
2014-01-01
期刊：
影响因子：
12.3
通讯作者：
Buchrieser, Carmen
中科院分区：
文献类型：
--
作者：
Gomez-Valero, Laura;Rusniok, Christophe;Buchrieser, Carmen
背景：军团菌属包括60多种。然而，嗜肺乳杆菌和长滩乳杆菌单独导致95%以上的军团病。为了确定不同致病能力的遗传基础，我们对米达代氏乳杆菌、hackeliae乳杆菌和fallonii乳杆菌（LLAP10）的基因组进行了测序和比较，这三种细菌很少从人类中分离出来。结果：我们发现这些军团菌在变形虫和巨噬细胞中具有不同的毒力，这与它们在人类中的发生有关。我们对属于5个物种的11个军团菌基因组进行了比较分析，发现基因组含量高度异质性，超过60%的基因组代表物种特异性基因；这些包括一个完整的噬菌体在l.m icdadei，首次在军团菌基因组中发现。军团菌基因组中具有丰富的移动元件；许多编码IV型分泌系统的接合转移，指出他们的重要性适应属。Dot/Icm分泌系统是保守的，尽管核心底物组很小，因为在所有军团菌物种中仅存在300多个Dot/Icm效应基因中的24个。我们还发现了新的真核基序，包括染色质，突触短缩蛋白或网格蛋白/涂层自适应结构域。结论：军团菌基因组是高度动态的，主要由IV型分泌系统组成，而少数核心底物在不同物种之间是共享的。真核样蛋白和基序仍然是军团菌属的标志。参与氧结合、铁储存、宿主膜运输和某些Dot/Icm底物等关键因子是疾病相关菌株的特定特征。
Background: The genus Legionella comprises over 60 species. However, L. pneumophila and L. longbeachae alone cause over 95% of Legionnaires' disease. To identify the genetic bases underlying the different capacities to cause disease we sequenced and compared the genomes of L. micdadei, L. hackeliae and L. fallonii (LLAP10), which are all rarely isolated from humans.Results: We show that these Legionella species possess different virulence capacities in amoeba and macrophages, correlating with their occurrence in humans. Our comparative analysis of 11 Legionella genomes belonging to five species reveals highly heterogeneous genome content with over 60% representing species-specific genes; these comprise a complete prophage in L. micdadei, the first ever identified in a Legionella genome. Mobile elements are abundant in Legionella genomes; many encode type IV secretion systems for conjugative transfer, pointing to their importance for adaptation of the genus. The Dot/Icm secretion system is conserved, although the core set of substrates is small, as only 24 out of over 300 described Dot/Icm effector genes are present in all Legionella species. We also identified new eukaryotic motifs including thaumatin, synaptobrevin or clathrin/coatomer adaptine like domains.Conclusions: Legionella genomes are highly dynamic due to a large mobilome mainly comprising type IV secretion systems, while a minority of core substrates is shared among the diverse species. Eukaryotic like proteins and motifs remain a hallmark of the genus Legionella. Key factors such as proteins involved in oxygen binding, iron storage, host membrane transport and certain Dot/Icm substrates are specific features of disease-related strains.