EAGER: Exploring Links between Iron and Phosphorus Nutrition of Antarctic Marine Phytoplankton

EAGER：探索南极海洋浮游植物铁和磷营养之间的联系

• 批准号: 2207011
• 负责人: Julie Granger
• 金额: $ 18.53万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2207011&HistoricalAwards=false
• 关键词: EAGER; Exploring; Links; between; Iron

Phytoplankton are microscopic single-celled plants that grow at the sun-lit surface of the ocean. In the Southern Ocean around Antarctica, phytoplankton live in sub-optimal conditions because the amount of iron in seawater is insufficient for growth. Moreover, the chemical composition of Southern Ocean phytoplankton is distinct from that in other ocean regions, with a higher proportion of phosphorus relative to other elements, a characteristic that ultimately influences the distribution of nutrients ocean-wide. The researchers hypothesize that the high phosphorus composition of phytoplankton in the Southern Ocean is caused by their low iron content. Specifically, they postulate that a phosphorus-rich molecule, phytic acid, is synthesized by phytoplankton in order to assist in the storage of iron in designated cellular compartments, such as vacuoles. Recent observations show that some phytoplankton can absorb phytic acid, suggesting that it may be produced by certain species. Phytic acid is pervasive in soils, wherein it aids absorption of iron via plant roots and could similarly help phytoplankton in the Southern Ocean acquire iron via the cell membranes. This project benefits the National Science Foundation's goals of improving understanding of interactions between the Southern Ocean and the global ocean, of expanding fundamental knowledge of Antarctic biota and associated processes by focusing on phytoplankton species unique to the Antarctic. As part of this project, the Department of Marine Sciences from the College of Liberal Arts and Sciences at the University of Connecticut will sponsor the recruitment, relocation and mentorship of a graduate student under-represented in the sciences.This project aims to determine whether the unusual elemental composition of phytoplankton at the Southern Ocean is a result of anemia. The work will query whether inositol hexakisphosphate (phytic acid) aids Antarctic phytoplankton acquire and store iron, resulting in an elevated fraction of cellular phosphorus relative to other elements. The researchers, including a graduate student, will conduct laboratory culture experiments with phytoplankton strains isolated from the Southern Ocean. They will grow cells in iron- deficient versus iron-replete media to see if their phosphorus content is higher in iron-deficient conditions. They will test whether cells grown with sufficient phosphorus acquire more iron, allowing them to grow better in iron-deficient conditions than cells deriving from phosphorus-poor conditions. They will also query whether cells grown in iron-deficient conditions achieve faster growth rates in the presence of phytic acid. Results will inform the design of CRISPR mutants with which to investigate phosphorus and iron co-metabolism in Antarctic marine phytoplankton.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

浮游植物是生长在阳光照射的海洋表面的微小单细胞植物。在南极洲周围的南大洋，浮游植物的生活条件并不理想，因为海水中的铁含量不足以生长。此外，南大洋浮游植物的化学成分与其他海洋区域不同，磷相对其他元素的比例较高，这一特征最终影响了全海洋营养物质的分布。研究人员推测，南大洋浮游植物的高磷成分是由于其铁含量低造成的。具体来说，他们假设浮游植物合成富含磷的分子植酸，以帮助在指定的细胞区室（例如液泡）中储存铁。最近的观察表明，一些浮游植物可以吸收植酸，这表明植酸可能是由某些物种产生的。植酸在土壤中普遍存在，它有助于植物根部吸收铁，同样可以帮助南大洋的浮游植物通过细胞膜获取铁。该项目有利于国家科学基金会的目标，即通过关注南极独特的浮游植物物种，增进对南大洋和全球海洋之间相互作用的了解，扩大南极生物群和相关过程的基础知识。作为该项目的一部分，康涅狄格大学文理学院海洋科学系将资助一名在科学领域代表性不足的研究生的招募、搬迁和指导。该项目旨在确定是否南大洋浮游植物的异常元素组成是贫血的结果。这项工作将询问肌醇六磷酸（植酸）是否有助于南极浮游植物获取和储存铁，从而导致细胞磷相对于其他元素的比例升高。研究人员，包括一名研究生，将对从南大洋分离出来的浮游植物菌株进行实验室培养实验。他们将在缺铁和铁充足的培养基中培养细胞，看看它们的磷含量在缺铁条件下是否更高。他们将测试在充足的磷条件下生长的细胞是否能够获得更多的铁，从而使它们在缺铁条件下比在缺磷条件下生长的细胞生长得更好。他们还将询问在缺铁条件下生长的细胞在植酸存在下是否能实现更快的生长速度。结果将为 CRISPR 突变体的设计提供信息，用于研究南极海洋浮游植物中磷和铁的共代谢。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。