Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA.
Nat Commun. 2020 Apr 6;11(1):1710. doi: 10.1038/s41467-020-15507-2.
The discovery of eukaryotic giant viruses has transformed our understanding of the limits of viral complexity, but the extent of their encoded metabolic diversity remains unclear. Here we generate 501 metagenome-assembled genomes of Nucleo-Cytoplasmic Large DNA Viruses (NCLDV) from environments around the globe, and analyze their encoded functional capacity. We report a remarkable diversity of metabolic genes in widespread giant viruses, including many involved in nutrient uptake, light harvesting, and nitrogen metabolism. Surprisingly, numerous NCLDV encode the components of glycolysis and the TCA cycle, suggesting that they can re-program fundamental aspects of their host's central carbon metabolism. Our phylogenetic analysis of NCLDV metabolic genes and their cellular homologs reveals distinct clustering of viral sequences into divergent clades, indicating that these genes are virus-specific and were acquired in the distant past. Overall our findings reveal that giant viruses encode complex metabolic capabilities with evolutionary histories largely independent of cellular life, strongly implicating them as important drivers of global biogeochemical cycles.
真核巨型病毒的发现改变了我们对病毒复杂性极限的认识，但它们所编码的代谢多样性的程度仍不清楚。在这里，我们从全球各地的环境中生成了 501 个核质大 DNA 病毒（NCLDV）的宏基因组组装基因组，并分析了它们所编码的功能能力。我们报告了广泛存在的巨型病毒中代谢基因的惊人多样性，包括许多参与营养吸收、光捕获和氮代谢的基因。令人惊讶的是，许多 NCLDV 编码糖酵解和 TCA 循环的成分，这表明它们可以重新编程宿主中央碳代谢的基本方面。我们对 NCLDV 代谢基因及其细胞同源物的系统发育分析揭示了病毒序列明显聚类到不同的进化枝中，表明这些基因是病毒特异性的，并且是在遥远的过去获得的。总的来说，我们的研究结果表明，巨型病毒编码具有复杂代谢能力的基因，其进化历史在很大程度上独立于细胞生命，这强烈表明它们是全球生物地球化学循环的重要驱动因素。
