EDGE FGT: Genetic Tools for Picocyanobacteria that Dominate the Oceans

EDGE FGT：主宰海洋的微微蓝藻的遗传工具

• 批准号: 2035181
• 负责人: Sallie Chisholm
• 金额: $ 55万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2035181&HistoricalAwards=false
• 关键词: EDGE; FGT; Genetic; Tools; Picocyanobacteria

As the most abundant photosynthetic organism on the planet, the marine cyanobacterium Prochlorococcus plays a central role in providing energy and nutrients to ocean food webs. This species alone fixes approximately as much carbon dioxide annually as global croplands. Understanding the link between the diverse genes of Prochlorococcus and its central role in ocean metabolism is hindered by our inability to modify its genes to test various hypotheses. Building on recent progress, this project aims to develop two distinct but parallel approaches to the challenge. In the first, barriers to the introduction of foreign DNA to Prochlorococcus will be bypassed by exploiting a system of newly discovered genetic elements that are found in some Prochlorococcus strains. In the second, approaches to trigger mechanisms that allow cells to take up and integrate new genes into their cellular machinery will be developed. Once developed, these approaches would allow better understanding of the link between Prochlorococcus genes and the ocean environment, which is critical for characterizing the role ocean processes play in regulating the global carbon cycle. These advances will also provide a blueprint for the development of similar methodologies for studying other microbial organisms. Finally, developing these technologies is a critical first step in enabling Prochlorococcus as a potential chassis for artificial photosynthesis. Since it has the smallest genome of any photosynthetic cell, Prochlorococcus is already the most basic photosynthetic machine occurring in nature, making it the ideal candidate for developing the tools that would enable bioengineering. The tools this project aims to develop would provide immense potential for new inquiry and biotechnology applications. This project provides support for graduate students, a postdoctoral research associate, and two technicians. Over the past three decades, the cyanobacterium Prochlorococcus, notable for its numerical dominance of the oceans and enormous genetic diversity, has been developed as a model organism for cross-scale systems biology. While each cell has around 2000 genes, the total unique gene content of the global Prochlorococcus ‘collective’ likely exceeds 80,000 genes, most of which have unknown function. Thus, despite their central role in ocean metabolism, the relationship between Prochlorococcus’ diverse genetic content, and the selective pressures that have shaped it, is only beginning to be understood. Progress on this challenge has been stalled by the lack of a genetic system. In previous work supported by the EDGE program, the researchers developed a method of introducing exogenous DNA into Prochlorococcus cells, which represented a significant step forward in genomic manipulation. In the process, a system of mobile genetic elements was discovered, which represent a promising new tool for integration of exogenous DNA into the Prochlorococcus, electroporation delivered tycheposons that are constructed with native genetic elements. A second approach to be developed utilizes a novel transposon-based screen to identify conditions for triggering natural competence activity among Prochlorococcus and will result in a genome-wide map of promising integration sites. Both approaches have the advantage of utilizing DNA from Prochlorococcus itself, which should more effectively bypass cell defenses against exogenous DNA.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.

作为地球上最丰富的照片同步生物，海洋蓝细菌占地氯环球菌在为海洋食品网提供能量和营养方面起着核心作用。仅该物种每年与全球农田一样，每年固定二氧化碳。我们无法修改其基因以检验各种假设的基因，从而阻碍了核菌的潜水基因与其在海洋代谢中的核心作用之间的联系。在最近的进步的基础上，该项目旨在为挑战开发两种不同但平行的方法。首先，通过利用在某些前氯环球菌菌株中发现的新发现的遗传元素的系统来绕开外源性DNA向核球菌引入前氯环球菌的障碍。第二，将开发触发细胞接收并整合到其细胞机械中的机制的方法。一旦开发，这些方法将可以更好地理解核球菌与海洋环境之间的联系，这对于表征海洋过程在计算全球碳循环中所扮演的角色至关重要。这些进步还将为开发研究其他微生物的类似方法提供蓝图。最后，开发这些技术是使甲氯环球菌作为人工光合作用的潜在底盘的关键第一步。由于它具有任何光同时性细胞中最小的基因组，因此，氯环球菌已经是自然界中最基本的光合作用机器，使其成为开发能够实现生物工程的工具的理想候选者。该项目旨在开发的工具将为新的查询和生物技术应用提供巨大的潜力。该项目为研究生，一名博士后研究助理和两名技术人员提供了支持。在过去的三十年中，蓝细菌的核酸菌群以其海洋的数值优势和巨大的遗传多样性而闻名，已被开发为跨尺度系统生物学的模型生物。尽管每个细胞都有大约2000个基因，但全局核酸群体“集体”的总体基因含量可能超过80,000个基因，其中大多数具有未知的功能。这是在探索海洋代谢中的核心作用，proColococus的不同遗传含量与塑造它的选择性压力之间的关系，才开始被理解。缺乏遗传系统，这一挑战的进展已经停滞了。在Edge计划支持的先前工作中，研究人员开发了一种将外源性DNA引入核酸细胞的方法，这代表了基因组操作中迈出的重要一步。在此过程中，发现了一种移动遗传元素系统，它代表了将外源性DNA整合到核酸核酸中的有希望的新工具，电穿孔传递了由天然遗传元素构建的tycheposon。要开发的第二种方法利用基于新的转座子的屏幕来识别触发甲氯环球菌自然能力活动的条件，并将导致全基因组的有希望的整合位点图。两种方法都具有使用甲氯环球菌本身的DNA的优势，该奖项应更有效地绕过针对外源性DNA的细胞防御措施。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响来评估NSF的法定任务。