Iron and Light Limitation in Ecologically Important Polar Diatoms: Comparative Transcriptomics and Development of Molecular Indicators

具有重要生态意义的极地硅藻中铁和光的限制：比较转录组学和分子指标的开发

• 批准号: 1341479
• 负责人: Adrian Marchetti
• 金额: $ 26.02万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341479&HistoricalAwards=false
• 关键词: Iron; Light; Limitation; Ecologically; Important

The Southern Ocean surrounding Antarctica is changing rapidly in response to Earth's warming climate. These changes will undoubtedly influence communities of primary producers (the organisms at the base of the food chain, particularly plant-like organisms using sunlight for energy) by altering conditions that influence their growth and composition. Because primary producers such as phytoplankton play an important role in global biogeochemical cycling, it is essential to understand how they will respond to changes in their environment. The growth of phytoplankton in certain regions of the Southern Ocean is constrained by steep gradients in chemical and physical properties that vary in both space and time. Light and iron have been identified as key variables influencing phytoplankton abundance and distribution within Antarctic waters. Microscopic algae known as diatoms are dominant members of the phytoplankton and sea ice communities, accounting for significant proportions of primary production. The overall objective of this project is to identify the molecular bases for the physiological responses of polar diatoms to varying light and iron conditions. The project should provide a means of evaluating the extent these factors regulate diatom growth and influence net community productivity in Antarctic waters. The project will also further the NSF goals of making scientific discoveries available to the general public and of training new generations of scientists. It will facilitate the teaching and learning of polar-related topics by translating the research objectives into readily accessible educational materials for middle-school students. This project will also provide funding to enable a graduate student and several undergraduate students to be trained in the techniques and perspectives of modern biology. Although numerous studies have investigated how polar diatoms are affected by varying light and iron, the cellular mechanisms leading to their distinct physiological responses remain unknown. Using comparative transcriptomics, the expression patterns of key genes and metabolic pathways in several ecologically important polar diatoms recently isolated from Antarctic waters and grown under varying iron and irradiance conditions will be examined. In addition, molecular indicators for iron and light limitation will be developed within these polar diatoms through the identification of iron- and light-responsive genes -- the expression patterns of which can be used to determine their physiological status. Upon verification in laboratory cultures, these indicators will be utilized by way of metatranscriptomic sequencing to examine iron and light limitation in natural diatom assemblages collected along environmental gradients in Western Antarctic Peninsula waters. In order to fully understand the role phytoplankton play in Southern Ocean biogeochemical cycles, dependable methods that provide a means of elucidating the physiological status of phytoplankton at any given time and location are essential.

南极洲周围的南大洋正在迅速变化，以应对地球变暖的气候。这些变化无疑将通过改变影响初级生产者生长和组成的条件，影响初级生产者的群落(食物链底部的生物体，特别是利用阳光作为能源的植物类生物体)。由于浮游植物等初级生产者在全球生物地球化学循环中发挥着重要作用，了解它们将如何应对环境变化是至关重要的。南大洋某些区域的浮游植物生长受到化学和物理性质的陡峭梯度的限制，这些性质在空间和时间上都不同。光和铁已被确定为影响南极水域浮游植物丰度和分布的关键变量。被称为硅藻的微型藻类是浮游植物和海冰群落的主要成员，占初级生产力的很大比例。该项目的总体目标是确定极地硅藻对不同的光和铁条件做出生理反应的分子基础。该项目应提供一种手段来评估这些因素在多大程度上调节了南极水域的硅藻生长和影响净群落生产力。该项目还将推动NSF向公众提供科学发现和培训新一代科学家的目标。它将通过将研究目标转化为中学生容易获得的教育材料，促进与极地有关的主题的教和学。该项目还将提供资金，使一名研究生和几名本科生能够接受现代生物学技术和视角的培训。虽然许多研究已经研究了不同的光和铁是如何影响极地硅藻的，但导致它们不同生理反应的细胞机制仍然不清楚。利用比较转录组学，将研究最近从南极水域分离的几种具有重要生态意义的极地硅藻的关键基因和代谢途径的表达模式，这些硅藻在不同的铁和光照条件下生长。此外，通过鉴定铁和光反应基因--其表达模式可用于确定它们的生理状态--将在这些极地硅藻中开发铁和光限制的分子指示器。在实验室培养中验证后，这些指示剂将通过后转录测序的方式来检查在南极半岛西部水域沿环境梯度收集的天然硅藻组合中的铁和光限制。为了充分了解浮游植物在南大洋生物地球化学循环中的作用，必须有可靠的方法来阐明浮游植物在任何特定时间和地点的生理状态。