UPMC Univ Paris 06 and CNRS, UMR 7621, Observatoire océanologique, 66650, Banyuls-sur-Mer, France.
Environ Microbiol Rep. 2010 Apr;2(2):313-21. doi: 10.1111/j.1758-2229.2010.00138.x. Epub 2010 Feb 8.
Although large DNA viruses of eukaryotic algae represent a major force in shaping populations of plankton, knowledge about them is often limited to their overall diversity, abundance, and the flux of their constituent matter between ecosystem compartments. In order to gain insight about the genetics and structure of such populations, we used an easily cultivable model unicellular algal species, Ostreococcus tauri (Prasinophyceae), to monitor and compare populations of viruses in different marine environments. The abundance of O. tauri viruses showed very large temporal fluctuations, but remarkably was more than two orders of magnitude higher in lagoons than in coastal waters. We analysed 161 individual viruses found after plating out for lysis plaques on the host during a time series of water samplings. The haplotypes of viruses infecting our host strain were determined by sequence analysis of the partial DNA polymerase gene, permitting a spatiotemporal analysis of their population structure. We found 48 haplotypes, only the two most abundant ones being shared among all of the three study sites (lagoon, coastal and offshore), supporting the hypothesis that there is great diversity among the viruses infecting one host strain. However, our data suggest that the population structure differ between lagoons and coastal sea.
尽管真核藻类的大型 DNA 病毒是塑造浮游生物种群的主要力量，但人们对它们的了解通常仅限于它们的总体多样性、丰度以及它们在生态系统隔室之间的物质通量。为了深入了解这些种群的遗传学和结构，我们使用一种易于培养的单细胞藻类模式物种——Ostreococcus tauri（绿藻门），来监测和比较不同海洋环境中的病毒种群。O. tauri 病毒的丰度显示出非常大的时间波动，但令人惊讶的是，在泻湖中的丰度比在沿海水域高两个数量级以上。我们分析了在宿主上进行噬菌斑平板培养的时间序列水样中发现的 161 个个体病毒。通过对部分 DNA 聚合酶基因的序列分析确定了感染我们宿主株的病毒的单倍型，从而可以对其种群结构进行时空分析。我们发现了 48 种单倍型，只有两种最丰富的单倍型在所有三个研究地点（泻湖、沿海和近海）中都存在，支持了感染一种宿主株的病毒存在巨大多样性的假设。然而，我们的数据表明，泻湖和沿海水域之间的病毒种群结构存在差异。
