Collaborative research: Characterization of Synechococcus-cyanophage interactions across phylogenetic and temporal scales

合作研究：跨系统发育和时间尺度的聚球藻-噬藻体相互作用的表征

• 批准号: 2023175
• 负责人: Nathan Ahlgren
• 金额: $ 72.48万
• 依托单位: Clark University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2023175&HistoricalAwards=false
• 关键词: Collaborative; research; Characterization; Synechococcus; cyanophage

Viral infection influences the flow of nutrients in the oceans and the diversity and structure of ecologically important microbial communities. Understanding which viruses infect which hosts is critical to understanding the exact impact of viruses, but there are still critical gaps in knowledge about how widely viruses can infect specific bacteria types and how this can change over time. This project includes the isolation and characterization of hundreds of co-occurring photosynthetic bacteria (cyanobacteria from the genus Synechococcus) and viruses that infect them (cyanophage) from Narragansett Bay, Rhode Island to assess the degree to which they can infect each other and identify specific genes that control cross-infection. DNA collected for over 10 years from Narragansett Bay is used to track Synechococcus and cyanophage communities to determine how virus-host interactions play out in shaping the diversity of natural Synechococcus and cyanophage communities over seasonal cycles and from year to year. This work provides knowledge of how individual viral-host interactions in a natural community can lead to the stable co-existence of particular species of viruses and bacteria in a coastal ecosystem over time. This project supports 15 undergraduate student researchers, a graduate student and a postdoctoral fellow who also receives training in effective practices in science teaching. Integration of the study’s results into undergraduate courses and outreach activities facilitates authentic opportunities for students to contribute to research and engagement of local junior and senior high school students.The team of scientists and students are conducting a phylogenetically-informed study of natural communities of co-occurring Synechococcus and cyanophage, a model tractable system in Narragansett Bay, to characterize phage-host interactions across different scales of diversity and time. The team’s goal is to isolate a large collection of ~100 Synechococcus and ~200 cyanophage from Narragansett Bay and to conduct infection assays and comparative genomics on these isolates. They employ amplicon sequencing of highly variable loci for both Synechococcus and cyanophage to characterize community dynamics across broad to fine genetic scales—ecotypes to within-species variants—for 10 years of archived monthly samples and a new weekly time-series over two years. These studies address the following three key questions: 1) Are there inherent boundaries of genetic relatedness (i.e. ecotype, species, or finer levels) at which the patterns of infection networks fundamentally shift from being mostly nested to mostly modular? (2) What are the underlying mechanisms and genetic loci that determine the boundaries of infection, i.e., host range and phage susceptibility? and, (3) How do host-phage interactions at different phylogenetic levels influence community structure over short (weeks to months) and long (year-to-year) time scales? Results from this project help to better understand how phytoplankton and bacterioplankton communities are shaped by viral predation and how host and phage diversity is created, maintained, and structured in the oceans.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.

病毒感染影响海洋中营养物质的流动以及具有重要生态意义的微生物群落的多样性和结构，了解哪些病毒感染哪些宿主对于了解病毒的确切影响至关重要，但对于病毒的传播范围仍存在严重的认识空白。感染特定的细菌类型以及这种情况如何随着时间的推移而变化。该项目包括数百种同时存在的光合细菌（来自聚球藻属的蓝藻）和感染它们的病毒的分离和表征。来自罗德岛州纳拉甘西特湾的噬藻体，以评估它们相互感染的程度，并识别控制交叉感染的特定基因。 10 多年来从纳拉甘西特湾收集的 DNA 用于追踪聚球藻和噬藻体群落，以确定它们如何相互感染。病毒与宿主的相互作用在季节性周期和逐年塑造自然聚球藻和噬藻体群落的多样性方面发挥着作用，这项工作提供了有关自然群落中个体病毒与宿主如何相互作用的知识。随着时间的推移，可以导致特定物种的病毒和细菌在沿海生态系统中稳定共存。该项目支持 15 名本科生研究人员、一名研究生和一名博士后研究员，他们还接受了科学教学整合的有效实践培训。该研究的结果纳入本科课程和推广活动，为学生提供真正的机会为当地初中生和高中生的研究和参与做出贡献。科学家和学生团队正在对共生的自然群落进行系统发育研究聚球藻和噬藻体是纳拉甘西特湾的一种易处理系统模型，用于表征不同规模和时间范围内的噬菌体-宿主相互作用。该团队的目标是从纳拉甘西特湾分离出大量约 100 个聚球藻和约 200 个噬藻体，并进行感染。他们对这些分离株进行了分析和比较基因组学，对聚球藻和噬藻体进行了高度可变基因座的扩增子测序来表征。这些研究解决了以下三个关键问题：从广泛到精细的遗传尺度（生态型到种内变异），对 10 年存档的每月样本和两年内的新每周时间序列进行了研究。遗传相关性（即生态型、物种或更精细的水平），感染网络的模式从根本上从嵌套型转变为模块化型？（2）决定感染边界的潜在机制和遗传位点是什么？即宿主范围和噬菌体易感性？以及，（3）不同系统发育水平的宿主-噬菌体相互作用如何影响短期（几周到几个月）和长期（每年）时间范围内的群落结构？更好地了解浮游植物和浮游细菌群落如何通过病毒捕食而形成，以及宿主和噬菌体多样性如何在海洋中创建、维持和构建。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。