Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
USDA National Wildlife Research Center, Fort Collins, Colorado, USA.
J Virol. 2014 Jul;88(14):7727-37. doi: 10.1128/JVI.00473-14. Epub 2014 Apr 16.
Mountain lions (Puma concolor) throughout North and South America are infected with puma lentivirus clade B (PLVB). A second, highly divergent lentiviral clade, PLVA, infects mountain lions in southern California and Florida. Bobcats (Lynx rufus) in these two geographic regions are also infected with PLVA, and to date, this is the only strain of lentivirus identified in bobcats. We sequenced full-length PLV genomes in order to characterize the molecular evolution of PLV in bobcats and mountain lions. Low sequence homology (88% average pairwise identity) and frequent recombination (1 recombination breakpoint per 3 isolates analyzed) were observed in both clades. Viral proteins have markedly different patterns of evolution; sequence homology and negative selection were highest in Gag and Pol and lowest in Vif and Env. A total of 1.7% of sites across the PLV genome evolve under positive selection, indicating that host-imposed selection pressure is an important force shaping PLV evolution. PLVA strains are highly spatially structured, reflecting the population dynamics of their primary host, the bobcat. In contrast, the phylogeography of PLVB reflects the highly mobile mountain lion, with diverse PLVB isolates cocirculating in some areas and genetically related viruses being present in populations separated by thousands of kilometers. We conclude that PLVA and PLVB are two different viral species with distinct feline hosts and evolutionary histories. Importance: An understanding of viral evolution in natural host populations is a fundamental goal of virology, molecular biology, and disease ecology. Here we provide a detailed analysis of puma lentivirus (PLV) evolution in two natural carnivore hosts, the bobcat and mountain lion. Our results illustrate that PLV evolution is a dynamic process that results from high rates of viral mutation/recombination and host-imposed selection pressure.
美洲狮（Puma concolor）在北美洲和南美洲都感染了美洲狮慢病毒 B 型（PLVB）。第二种高度分化的慢病毒 clade，PLVA，感染南加州和佛罗里达州的美洲狮。这两个地理区域的山猫（Lynx rufus）也感染了 PLVA，迄今为止，这是在山猫中发现的唯一一种慢病毒株。我们对全长 PLV 基因组进行了测序，以表征 PLV 在山猫和美洲狮中的分子进化。在两个 clade 中都观察到低序列同源性（平均成对同一性 88%）和频繁重组（每 3 个分离物分析一个重组断点）。病毒蛋白的进化模式明显不同；Gag 和 Pol 中的序列同源性和负选择最高，而 Vif 和 Env 中的最低。PLV 基因组中共有 1.7%的位点受到正选择的影响，表明宿主施加的选择压力是塑造 PLV 进化的重要力量。PLVA 株具有高度的空间结构，反映了其主要宿主山猫的种群动态。相比之下，PLVB 的系统地理学反映了高度移动的美洲狮，在一些地区共同循环存在多种 PLVB 分离株，而在相隔数千公里的种群中存在遗传相关的病毒。我们得出结论，PLVA 和 PLVB 是两种不同的病毒种，具有不同的猫科宿主和进化历史。重要性：了解自然宿主种群中的病毒进化是病毒学、分子生物学和疾病生态学的一个基本目标。在这里，我们对两种天然肉食动物宿主（山猫和美洲狮）中的美洲狮慢病毒（PLV）进化进行了详细分析。我们的结果表明，PLV 进化是一个动态过程，是由病毒突变/重组的高速率和宿主施加的选择压力导致的。
