RUI: High throughput culturing and ecophysiological analyses of low light adapted Prochlorococcus ecotypes

RUI：低光适应原绿球藻生态型的高通量培养和生态生理学分析

• 批准号: 0851288
• 负责人: Lisa Moore
• 金额: $ 44.53万
• 依托单位: University of Southern Maine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0851288&HistoricalAwards=false
• 关键词: RUI; throughput; culturing; ecophysiological; analyses

The marine cyanobacterium, Prochlorococcus, is the smallest yet most abundant known phototroph on the planet and contributes significantly to primary production and biogeochemical cycling in the world's open oceans. Since its first description 20 years ago, this organism has become a well-studied marine microbe that is being developed as a model system for cross-scale systems biology. At least 26 isolates have been obtained since 1988, from which two distinct ecotypes were identified based on the relative photophysiological characteristics: high-light (HL) adapted and low-light (LL) adapted. More than 80% of the isolates belong to the HL adapted ecotype, which is composed of at least two distinct phylogenetic clades. The other isolates (6) are considered LL adapted and are spread among several phylogenetic clades, two of which are represented by single cultured isolates. Evidence indicates that the two HL adapted clades likely evolved from differences in temperature optima resulting in distinct horizontal distributions of their populations. What is not clear are the phenotypic and/or ecological underpinnings of the different LL adapted clades and the distributions of these clades in space and time, in large part because there are so few isolates representing each clade. Thus, despite the relatively large number of isolates and data on Prochlorococcus, only half the story, that of the more dominant HL adapted ecotypes, is understood in terms of the phylogenetic relationships and distributions. This project will study the physiological characteristics that contribute to the ecology and evolution of different phylogenetic clades that make up the LL adapted Prochlorococcus ecotype. This characterization will be achieved through high throughput culturing and physiological assessment experiments that utilize multi-well plates for purifying new LL adapted isolates, physiological determinations, and a 96-well sampling system attached to a flow cytometer.Broader Impacts: This project will isolate new, axenic cultures with accompanying ecophysiological and phylogenetic information that could be used by biological oceanographers, biogeochemical modelers, microbiologists and evolutionary biologists for further studies of natural population distributions, physiological mechanisms, genomics, transcriptomics, and proteomics of the world's most abundant phototroph. For instance, the 16S-23S rRNA sequences can be used to redesign or develop new primers for environmental detection of LL adapted Prochlorococcus populations and specific ecotypes, which in turn will enable researchers to begin to understand their ecological role in the deeper euphotic zone. New Prochlorococcus isolates will be made available to other researchers as well as deposited in a larger culture collection such as the Center for the Culture of Marine Phytoplankton. Gene sequences will be deposited in the public database, GenBank, and the results from this study will provide information to choose specific strains for further genome sequence analysis. In addition, this project will also provide research opportunities and financial support for several undergraduates to carry out research projects, a MS student in Biology, and the first University of Maine System Cooperative PhD student in Microbiology at USM.

海洋蓝藻，原氯球菌，是地球上已知的最小但最丰富的光生生物，对世界开放海洋的初级生产力和生物地球化学循环做出了重要贡献。自从20年前首次描述以来，这种生物已经成为一种被充分研究的海洋微生物，正在被开发为跨尺度系统生物学的模式系统。自1988年以来，至少已经获得了26个菌株，根据相对光生理特性，从这些菌株中鉴定出两种不同的生态型：适应强光(HL)和适应弱光(LL)。80%以上的菌株属于HL适应生态型，至少由两个不同的系统发育分支组成。其他菌株(6)被认为是LL适应的，分布在几个系统发育分支中，其中两个是由单个培养的菌株代表的。证据表明，这两个适应HL的支系可能是由于温度最佳点的差异而进化而来的，从而导致了它们的种群在水平上的不同分布。目前尚不清楚的是不同适应LL的分支的表型和/或生态基础，以及这些分支在空间和时间上的分布，这在很大程度上是因为代表每个分支的分离物太少。因此，尽管关于原氯球菌的分离株和数据相对较多，但从系统发育关系和分布的角度来看，只有一半的故事被理解，即更具优势的HL适应生态型。本项目将研究组成LL适应原氯球菌生态型的不同系统发育分支的生理特性，这些特性有助于生态和进化。这一特征将通过高通量培养和生理评估实验实现，这些实验利用多孔板纯化适应LL的新菌株、生理测定和连接到流动细胞仪的96孔采样系统。广泛影响：该项目将分离新的无菌培养物以及伴随的生态生理和系统发育信息，这些信息可供生物海洋学家、生物地球化学模型师、微生物学家和进化生物学家用于进一步研究世界上最丰富的光生生物的自然种群分布、生理机制、基因组学、转录组学和蛋白质组学。例如，16S-23S rRNA序列可用于重新设计或开发新的引物，用于对适应LL的原氯球菌种群和特定生态型进行环境检测，这反过来将使研究人员能够开始了解它们在更深的真光带中的生态作用。新的原氯球菌分离株将提供给其他研究人员，并保存在更大的培养库中，如海洋浮游植物培养中心。基因序列将保存在公共数据库GenBank中，这项研究的结果将为选择特定菌株进行进一步的基因组序列分析提供信息。此外，该项目还将为几名本科生提供研究机会和资金支持，以开展研究项目，其中包括一名生物学硕士学生，以及USM缅因州大学系统合作微生物学博士生。