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.

南极周围的南大洋正在响应地球温暖的气候，正在迅速变化。这些变化无疑会通过改变影响其生长和成分的条件，无疑会影响主要生产者的群落（食物链底部的生物，尤其是使用阳光的植物样生物）。由于诸如浮游植物之类的主要生产商在全球生物地球化学循环中起着重要作用，因此必须了解他们将如何应对环境变化。南大洋某些地区浮游植物的生长受到化学和物理特性的陡峭梯度的限制，它们在时空和时间上都不同。光和铁已被确定为影响南极水域内浮游植物丰度和分布的关键变量。被称为硅藻的微量藻类是浮游植物和海冰群落的主要成员，占主要生产的显着比例。该项目的总体目的是确定极性硅藻对不同光和铁条件的生理反应的分子碱基。该项目应提供一种评估这些因素调节硅藻生长的程度并影响南极水域净生产力的方法。 该项目还将进一步为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易于获得的教育材料来促进与极性相关的主题的教学和学习。 该项目还将提供资金，以使研究生和几位本科生可以接受现代生物学的技术和观点的培训。尽管许多研究研究了极性硅藻如何受光和铁的影响，但导致其独特生理反应的细胞机制仍然未知。使用比较转录组学，将研究从南极水分离出来的几个生态重要的极性硅藻中关键基因和代谢途径的表达模式，并将研究在不同的铁和辐照度条件下生长。 此外，通过鉴定铁和光反应基因，将在这些极性硅藻中开发铁和光限制的分子指标 - 该基因的表达模式可用于确定其生理状态。在实验室培养物进行验证后，将通过元文字测序使用这些指标来检查沿西南极半岛西部环境梯度收集的自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周期中的作用，可靠的方法提供了一种在任何给定时间和位置阐明浮游植物的生理状态的方法。