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Giant viruses in the open ocean: Is large size adaptive where cells are scarce?

公海中的巨型病毒：大尺寸是否能适应细胞稀缺的环境？

基本信息

批准号：
2129697
负责人：
Kyle Edwards
金额：
$ 117.62万
依托单位：
University of Hawaii
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-15 至 2024-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2129697&HistoricalAwards=false
关键词：
Giant viruses open ocean large

项目摘要

Viruses can infect all forms of life. Viruses are highly diverse, and one aspect of diversity is size: genomes of viruses vary more than a thousandfold in length, and the size of viral particles varies nearly a millionfold. The discovery of “giant” viruses was astounding because they can be physically larger and code for more genes than many free-living microorganisms. There is growing evidence that giant viruses are widespread and diverse in the ocean, but much about their ecology remains unknown. What critical ecological tradeoffs vary with virus size, allowing small and large viruses to coexist? Do these tradeoffs cause the distribution of virus sizes to vary across habitats? This project aims to answer these questions for viruses that infect phytoplankton, the microscopic plants that are the foundation of ocean productivity. This research can also influence a diverse array of scientific fields because virus size varies greatly in other ecosystems and host-associated microbiomes. The fundamental constraints on size may be broadly similar across systems, but the processes driving virus size have not been thoroughly investigated in any of them. This project supports the training of a postdoctoral researcher, two graduate students, and undergraduate students in integrative science that includes field, laboratory, and modeling components. National Science Foundation-supported Research Experience for Undergraduates and Tribal Colleges and Universities programs at UH Manoa that serve Pacific Islanders and other underrepresented groups are used for recruiting students. In addition, science outreach at public events in Hawai’i includes an interactive game to communicate ideas about giant viruses and their role in the ocean. Large viruses may have four advantages over smaller viruses: i) ability to infect a greater diversity of host genotypes, ii) better control of host metabolism, iii) large enough size to enter host cells by ingestion, and iv) greater persistence in the extracellular environment. These advantages may compensate for the advantages held by smaller viruses: higher contact rates with their hosts and greater offspring number per infection. The advantages of large size may be more consequential in oligotrophic habitats, where the microbial eukaryote community is primarily small phagotrophic flagellates (mixotrophs and heterotrophs), at low population densities, with resource-limited growth. The project goals are: (1) To test whether giant viruses indeed dominate in the oligotrophic ocean compared to a productive coastal location, as suggested by initial observations of this research team; (2) To test the above four hypotheses about the advantages of large size by conducting laboratory experiments with diverse viral isolates, and (3) To use an eco-evolutionary model of eukaryotic microbes and their viruses to explain observed size patterns.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

病毒可以感染所有形式的生命。病毒是高度多样的，多样性的一个方面是大小：病毒的基因组长度变化超过一千倍，病毒颗粒的大小变化近百万倍。“巨型”病毒的发现令人震惊，因为它们的体积比许多自由生活的微生物更大，编码的基因也更多。越来越多的证据表明，巨大的病毒在海洋中广泛存在，而且种类繁多，但关于它们的生态学仍有很多未知之处。什么关键的生态权衡随病毒大小而变化，允许小型和大型病毒共存？这些权衡是否会导致病毒大小的分布在不同的栖息地？该项目旨在回答这些感染浮游植物的病毒的问题，浮游植物是海洋生产力的基础。这项研究还可以影响各种科学领域，因为病毒大小在其他生态系统和宿主相关微生物组中差异很大。对病毒大小的基本限制在不同的系统中可能大致相似，但驱动病毒大小的过程在任何系统中都没有得到彻底的研究。该项目支持一名博士后研究员，两名研究生和本科生在综合科学，包括现场，实验室和建模组件的培训。国家科学基金会支持的本科生和部落学院和大学的研究经验在UH马诺阿，为太平洋岛民和其他代表性不足的群体服务的方案用于招收学生。此外，在夏威夷的公共活动中，科学宣传包括一个互动游戏，以交流有关巨型病毒及其在海洋中的作用的想法。大型病毒相对于小型病毒可能具有四个优势：i）感染更大多样性的宿主基因型的能力，ii）更好地控制宿主代谢，iii）足够大的尺寸以通过摄取进入宿主细胞，以及iv）在细胞外环境中更大的持久性。这些优势可能会弥补较小病毒的优势：与宿主的接触率较高，每次感染的后代数量较多。大尺寸的优势可能是更重要的贫营养的栖息地，其中微生物真核生物群落主要是小的吞噬鞭毛虫（兼养和异养），在低人口密度，资源有限的增长。该项目的目标是：（1）测试巨型病毒是否确实在贫营养海洋中占主导地位，与多产的沿海地区相比，正如该研究小组的初步观察所表明的那样;（2）通过对不同的病毒分离株进行实验室实验来检验上述关于大尺寸优势的四个假设，（3）采用生态-真核微生物及其病毒的进化模型，以解释观察到的大小模式。该奖项反映了NSF的法定使命，并已被认为值得支持，使用基金会的知识价值和更广泛的影响审查标准进行评估。