Viral control of microbial communities in Antarctic lakes

病毒在水生环境中很普遍，在那里，它们在一茶匙水中可以到达多达5亿个病毒颗粒。正在进行的病毒发现似乎证实了目前的理解，即所有形式的生命都可以容纳病毒并被病毒感染，病毒是地球上未被探索的遗传多样性的最大储存库之一。这项研究旨在更好地了解特定病毒与浮游植物宿主之间的相互作用，并确定这些病毒可能如何影响南极洲维斯特福尔德丘陵湖泊中存在的不同藻类群。这些湖泊(Ace、有机和深水)最初来自海洋，含有广泛的盐分条件，由于数千年来与世隔绝和低外部影响，具有类似广泛的物理化学特征。这些自然实验室可以检查微生物的过程和相互作用，而这些过程和相互作用在地球上的其他地方很难描述。该项目将产生广泛的基因组信息，这些信息将免费提供。该项目还将利用对病毒的研究和所采用的基因组方法来推进本科生的培训，并在缅因州为高中生提供有系统的非正式教育计划期间参与和促进对南极科学和微生物研究的理解。通过建立(主要)特定dsDNA病毒群在整个季节和年际周期中具有不同氧化还原条件的不同生境中的动态和相互作用，该项目将了解影响微生物群落动态的生物和非生物因素。这个项目不需要在南极洲进行实地考察。取而代之的是，调查人员将利用已经收集并存档的样本，这些样本来自三个同时测量物理化学信息的湖泊。通过由联合基因组研究所资助的社区科学计划(CSP)，将从选定的可用样本中产生约2TB的下一代测序(NGS)(包括元基因组、SSU rRNA扩增和单病毒基因组)。调查人员将利用生物信息学来询问这些序列数据库。特别是，他们将重点调查多克隆、类多克隆病毒、噬病毒体和大型dsDNA浮游植物病毒以及它们可能的真核微生物宿主的存在、系统发育和共存。生物信息学分析将与定量数字聚合酶链式反应和微生物协会网络分析相辅相成，从共同出现的空间和时间模式中检测特定的病毒？病毒？宿主相互作用。还将进行多变量分析和网络分析，以调查哪些非生物因素与三个湖泊内的浮游植物和病毒丰度、时间动态和观察到的病毒-浮游植物组合关系最密切。该项目的结果将增进对浮游植物及其病毒作为南极碳循环的重要组成部分的理解，海洋衍生的水生环境，以及可能在任何其他水生环境中。总体而言，这项工作将促进对独特南极环境适应的遗传基础的理解。

Viruses are prevalent in aquatic environments where they reach up to five hundred million virus particles in a teaspoon of water. Ongoing discovery of viruses seems to confirm current understanding that all forms of life can host and be infected by viruses and that viruses are one of the largest reservoirs of unexplored genetic diversity on Earth. This study aims to better understand interactions between specific viruses and phytoplankton hosts and determine how these viruses may affect different algal groups present within lakes of the Vestfold Hills, Antarctica. These lakes (Ace, Organic and Deep)were originally derived from the ocean and contain a broad range of saline conditions with a similarly broad range of physicochemical characteristics resulting from isolation and low external influence for thousands of years. These natural laboratories allow examination of microbial processes and interactions that would be difficult to characterize elsewhere on earth. The project will generate extensive genomic information that will be made freely available. The project will also leverage the study of viruses and the genomic approaches employed to advance the training of undergraduate students and to engage and foster an understanding of Antarctic science and studies of microbes during a structured informal education program in Maine for the benefit of high school students. By establishing the dynamics and interactions of (primarily) specific dsDNA virus groups in different habitats with different redox conditions throughout seasonal and inter annual cycles the project will learn about the biotic and abiotic factors that influence microbial community dynamics. This project does not require fieldwork in Antarctica. Instead, the investigators will leverage already collected and archived samples from three lakes that have concurrent measures of physicochemical information. Approximately 2 terabyte of Next Generation Sequencing (NGS) (including metagenomes, SSU rRNA amplicons and single virus genomes) will be generated from selected available samples through a Community Science Program (CSP) funded by the Joint Genome Institute. The investigators will employ bioinformatics to interrogate those sequence databases. In particular, they will focus on investigating the presence, phylogeny and co-occurrence of polintons, polinton-like viruses, virophages and large dsDNA phytoplankton viruses as well as of their putative eukaryotic microbial hosts. Bioinformatic analyses will be complemented with quantitative digital PCR and microbial association network analysis to detect specific virus?virus?host interactions from co-occurrence spatial and temporal patterns. Multivariate analysis and network analyses will also be performed to investigate which abiotic factors most closely correlate with phytoplankton and virus abundances, temporal dynamics, and observed virus-phytoplankton associations within the three lakes. The results of this project will improve understanding of phytoplankton and their viruses as vital components of the carbon cycle in Antarctic, marine-derived aquatic environments, and likely in any other aquatic environment. Overall, this work will advance understanding of the genetic underpinnings of adaptations in unique Antarctic environments.