Bautista Maria A, Black Jesse A, Youngblut Nicholas D, Whitaker Rachel J
Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, USA.
Viruses. 2017 May 19;9(5):120. doi: 10.3390/v9050120.
In the past decade, molecular surveys of viral diversity have revealed that viruses are the most diverse and abundant biological entities on Earth. In culture, however, most viral isolates that infect microbes are represented by a few variants isolated on type strains, limiting our ability to study how natural variation affects virus-host interactions in the laboratory. We screened a set of 137 hot spring samples for viruses that infect a geographically diverse panel of the hyperthemophilic crenarchaeon We isolated and characterized eight SIRVs ( rod-shaped viruses) from two different regions within Yellowstone National Park (USA). Comparative genomics revealed that all SIRV sequenced isolates share 30 core genes that represent 50-60% of the genome. The core genome phylogeny, as well as the distribution of variable genes (shared by some but not all SIRVs) and the signatures of host-virus interactions recorded on the CRISPR (clustered regularly interspaced short palindromic repeats) repeat-spacer arrays of hosts, identify different SIRV lineages, each associated with a different geographic location. Moreover, our studies reveal that SIRV core genes do not appear to be under diversifying selection and thus we predict that the abundant and diverse variable genes govern the coevolutionary arms race between SIRVs and their hosts.
在过去十年中，对病毒多样性的分子调查表明，病毒是地球上最多样化且数量最丰富的生物实体。然而在培养过程中，大多数感染微生物的病毒分离株仅由在模式菌株上分离出的少数变体代表，这限制了我们在实验室研究自然变异如何影响病毒与宿主相互作用的能力。我们在一组137个温泉样本中筛选了感染嗜热泉古菌的病毒，该古菌来自不同地理区域。我们从美国黄石国家公园的两个不同区域分离并鉴定了八种SIRV（杆状病毒）。比较基因组学显示，所有测序的SIRV分离株共享30个核心基因，这些基因占基因组的50 - 60%。核心基因组系统发育，以及可变基因（部分但非全部SIRV共享）的分布和宿主CRISPR（成簇规律间隔短回文重复序列）重复间隔阵列上记录的宿主 - 病毒相互作用特征，确定了不同的SIRV谱系，每个谱系与不同地理位置相关。此外，我们的研究表明，SIRV核心基因似乎未受到多样化选择，因此我们预测，丰富多样的可变基因主导着SIRV与其宿主之间的共同进化军备竞赛。
