Targeted and comparative viral community genomics of the Eastern North Pacific

北太平洋东部地区的目标和比较病毒群落基因组学

• 批准号: 0961947
• 负责人: Matthew Sullivan
• 金额: $ 57.67万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0961947&HistoricalAwards=false
• 关键词: Targeted; comparative; viral; community; genomics

Two climatically and biogeochemically important features characterize the Eastern North Pacific (ENP). This region encompasses one of the planet's largest oxygen minimum zones, and annually hosts a phytoplankton bloom that leads to some of the highest dimethyl sulfide (DMS) concentrations observed. Oxygen minimum zones (OMZs) play integral roles in marine biogeochemical cycles, as major sinks for nitrogen and sources for climatologically active trace gases including methane and nitrous oxide. There is increasing evidence that projected ocean warming and circulation changes is decreasing dissolved oxygen concentrations within the coastal and interior regions of the ENP, causing lateral and vertical OMZ expansion. This will have a direct effect on coastal benthic ecosystems and the productivity of marine fisheries, as well as potentially positive climatalogical feedbacks. In addition, the DMS produced in the ENP is a potential negative feedback for atmospheric warming through its role in atmospheric cloud formation, while it also accounts for approximately half of the planet's total biogenic sulfur flux. The PI of this project has collaborated with Dr. Steven Hallam (UBC) since June 2008 to archive viral community DNA, paired with high molecular weight genomic DNA from microbial biomass (since June 2006) and a rich synoptic oceanographic metadataset, along defined redox gradients in the ENP as part of the Canadian-funded Line P time series program. The viral samples focus on open-ocean station OSP and span surface waters, hypoxic interior, and upper and lower oxichypoxic transition zones. Microbial investigations, ongoing since 2006, have examined community diversity and population structure of indigenous microbial groups in the ENP. Time-series analyses have revealed dynamic seasonal changes, consistent with changing light, temperature, and nutrient conditions. However, little is known about the role that co-occurring viral communities play in modulating microbial community dynamics and responses to both water column hypoxia and massive DMS production and sulfur cycling. Marine viruses are responsible for the largest flux of carbon in the oceans by lysing microbial cells, while also encoding "host" metabolic genes. In the case of marine cyanobacteria, phage directly impact global carbon cycling by encoding ~60% of the core reaction center genes in surface water photosystems. Understanding coupled viral, microbiological and biogeochemical processes the ENP is critical to understand, predict, or one day possibly mitigate changes in productivity and trace gas cycling associated with OMZ expansion and changing DMS production. This project will investigate viral community diversity and metabolic capacity through viral metagenomes sampled along defined spatiotemporal gradients in the ENP. The endeavor is highly leveraged with funding already secured for sequencing 20 viral metagenomes, and their co-occurring microbial communities at high phylogenetic resolution using 16S hypervariable sequence tagging through the DOE JGI Community Sequencing Program and the Moore Foundation viral sequencing initiative. This project will identify relevant patterns of viral-host interaction with profound ecological and evolutionary consequences.Broader impacts: The microbial and viral sampling effort will be performed by post-docs and graduate students in the context of a 50+ year oceanographic sampling effort that allows these trainees see the vast biogeochemical and physical oceanographic measurements required to "survey" an ocean community. This project will expose undergraduates and high school students to the excitement of field-based oceanographic research through a combination of direct involvement in research, a Biosphere 2 "hands-on sampling training", and a new course at Tucson High School entitled "Ocean viruses: From isolates to genomes and metagenomes".

东北太平洋(ENP)有两个重要的气候和生物地球化学特征。该地区是地球上最大的含氧量最低地带之一，每年都会出现浮游植物水华，导致二甲基硫(DMS)浓度达到观测到的最高水平。氧最小区域在海洋生物地球化学循环中发挥着不可或缺的作用，是氮的主要汇，也是具有气候活性的痕量气体，包括甲烷和一氧化二氮的来源。越来越多的证据表明，预计的海洋变暖和环流变化正在减少ENP沿海和内陆地区的溶解氧浓度，导致OMZ横向和垂直扩张。这将对沿海底栖生态系统和海洋渔业的生产力以及潜在的气候反馈产生直接影响。此外，ENP产生的DMS通过其在大气云形成中的作用，对大气变暖具有潜在的负反馈作用，同时它也占地球总生物成因硫通量的大约一半。该项目的PI自2008年6月以来一直与Steven Hallam博士(UBC)合作，将病毒群落DNA与来自微生物生物量的高分子量基因组DNA配对(自2006年6月以来)，以及丰富的气象学海洋元数据集，以及作为加拿大资助的Line P时间序列计划的一部分，在ENP中定义的氧化还原梯度。病毒样本集中在公海OSP站和SPAN地表水、低氧内部以及上下低氧过渡区。自2006年以来一直在进行的微生物调查研究了ENP中土著微生物群体的群落多样性和种群结构。时间序列分析揭示了动态的季节变化，与变化的光、温度和营养条件一致。然而，关于共生病毒群落在调节微生物群落动态以及对水柱缺氧、大量DMS产生和硫循环的反应中所起的作用，人们知之甚少。海洋病毒通过裂解微生物细胞，同时编码“宿主”新陈代谢基因，负责海洋中最大的碳流量。以海洋蓝藻为例，噬菌体通过编码地表水体光系统中约60%的核心反应中心基因，直接影响全球碳循环。了解耦合的病毒、微生物和生物地球化学过程ENP对于了解、预测或在某一天可能缓解与OMZ扩大和改变DMS生产相关的生产力和痕量气体循环的变化至关重要。这个项目将通过在ENP中沿着定义的时空梯度采样的病毒元基因组来调查病毒群落的多样性和代谢能力。这项工作具有很高的杠杆作用，已获得资金，用于对20种病毒元基因组及其共生微生物群落进行测序，并通过美国能源部JGI社区测序计划和摩尔基金会病毒测序计划，使用16S高变量序列标签，以高系统发育分辨率对它们进行测序。该项目将确定病毒-宿主相互作用的相关模式，具有深远的生态和进化后果。广泛的影响：微生物和病毒采样工作将由博士后和研究生在50多年的海洋采样工作的背景下进行，使这些受训人员能够看到“调查”海洋群落所需的大量生物地球化学和物理海洋测量。该项目将通过直接参与研究、生物圈2“动手取样培训”和图森高中题为“海洋病毒：从分离株到基因组和元基因组”的新课程，使本科生和高中生接触到实地海洋学研究的兴奋。