: Among more than twenty species belonging to the class Mollecutes, Mycoplasma bovis is the most common cause of bovine mycoplasmosis in North America and Europe. Bovine mycoplasmosis causes significant economic loss in the cattle industry. The number of M. bovis positive herds recently has increased in North America and Europe. Since antibiotic treatment is ineffective and no efficient vaccine is available, M. bovis induced mycoplasmosis is primarily controlled by herd management measures such as the restriction of moving infected animals out of the herds and culling of infected or shedders of M. bovis. To better understand the population structure and genomic factors that may contribute to its transmission, we sequenced 147 M. bovis strains isolated from four different countries viz. USA (n = 121), Canada (n = 22), Israel (n = 3) and Lithuania (n = 1). All except two of the isolates (KRB1 and KRB8) were isolated from two host types i.e., bovine (n = 75) and bison (n = 70). We performed a large-scale comparative analysis of M. bovis genomes by integrating 103 publicly available genomes and our dataset (250 total genomes). Whole genome single nucleotide polymorphism (SNP) based phylogeny using M. agalactiae as an outgroup revealed that M. bovis population structure is composed of five different clades. USA isolates showed a high degree of genomic divergence in comparison to the Australian isolates. Based on host of origin, all the isolates in clade IV was of bovine origin, whereas majority of the isolates in clades III and V was of bison origin. Our comparative genome analysis also revealed that M. bovis has an open pangenome with a large breadth of unexplored diversity of genes. The function based analysis of autogenous vaccine candidates (n = 10) included in this study revealed that their functional diversity does not span the genomic diversity observed in all five clades identified in this study. Our study also found that M. bovis genome harbors a large number of IS elements and their number increases significantly (p = 7.8x10^-6) as the genome size increases. Collectively, the genome data and the whole genome-based population analysis in this study may help to develop better understanding of M. bovis induced mycoplasmosis in cattle.

中文翻译：

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牛支原体的人口基因组分析阐明了地理变异和与宿主类型相关的基因

：在二十余种，分属类Mollecutes，牛支原体是在北美和欧洲的牛支原体病的最常见原因。牛支原体病在养牛业中造成重大的经济损失。最近，北美和欧洲的牛分枝杆菌阳性牛群数量有所增加。由于抗生素治疗无效且没有有效的疫苗，因此牛分枝杆菌引起的支原体病主要由畜群管理措施控制，例如限制将感染的动物从畜群中移出以及剔除牛分枝杆菌的感染或脱落者。为了更好地了解可能有助于其传播的种群结构和基因组因素，我们对从四个不同国家分离的147株牛分枝杆菌进行了测序。美国（n = 121），加拿大（n = 22），以色列（n = 3）和立陶宛（n = 1）。除两个分离株（KRB1和KRB8）外，所有分离株均来自两种宿主类型，即牛（n = 75）和野牛（n = 70）。我们对牛分枝杆菌进行了大规模的比较分析通过整合103个公共可用基因组和我们的数据集（总共250个基因组）来实现基因组的整合。使用基于系统发生的全基因组的单核苷酸多态性（SNP）M. 无乳链球菌作为外类群透露，牛分枝杆菌种群结构由五个不同的进化枝。与澳大利亚分离株相比，美国分离株显示出高度的基因组差异。根据来源宿主，IV进化枝中的所有分离物均来自牛，而III和V进化枝中的大多数分离物均来自野牛。我们的比较基因组分析还显示，牛分枝杆菌具有开放的全基因组，具有广泛的未开发基因多样性。基于功能的自体候选疫苗分析（n = 这项研究中包括的10）揭示了它们的功能多样性并不涵盖在该研究中鉴定的所有五个进化枝中观察到的基因组多样性。我们的研究还发现，牛分枝杆菌基因组具有大量IS元素，并且随着基因组大小的增加，它们的数量显着增加（p = 7.8x10 ^-6）。总的来说，本研究中的基因组数据和基于全基因组的种群分析可能有助于加深对牛分枝杆菌引起的牛支原体病的了解。