Collaborative Research: Functional Genomic Investigations of Iron and Carbon Cycle Coupling in Select Keystone Marine Bacteria Heterotrophs

作为海洋环境中微生物生长所需的一种稀缺但必需的微量营养素，铁在支持海洋初级生产力方面发挥着关键作用，并与碳和其他营养物质的循环密切相关。近年来，人们对铁在海洋中的分布以及铁限制对浮游植物的影响的认识取得了重大进展。然而，关于海洋系统中铁和碳之间存在的广泛的生物地球化学联系，仍然存在许多问题。在这个网络中，细菌是一个至关重要且研究不足的节点。拟议的工作将在异养细菌的背景下探索海洋系统中碳和铁循环之间的联系，异养细菌是海洋有机质周转的主要驱动因素。该项目将支持一名博士后研究员，以及一名本科生实习生。加州大学圣地亚哥分校生物工程高级设计论文的学生将被培养开发与合成生物学相关的项目。该团队还将与Scripps教育联盟和圣地亚哥县教育办公室（SDCOE）合作举办为期3天的研讨会，为加州高中教师开发下一代科学标准和CA科学框架相关的活动和资源。教育活动将以与拟议研究有关的“现象”为基础，经过当地科学教师的适当测试和完善后，由SDCOE广泛传播。将采用功能基因组学方法，使用已被证明在其碳底物利用和生活方式策略方面代表光谱的模式生物。Alteromonas spp具有许多依赖tonb的外膜受体和水解酶能力，以其降解和同化复杂（即高分子量）海洋溶解有机物的能力而闻名。相比之下，研究充分的玫瑰杆菌，具有大量的膜内转运蛋白，专门运输低分子量的有机物。该项目提出了铁底物利用和铁相关生理如何影响这些生物已知的生态位特异性和影响碳处理的基本问题。这些问题将通过结合转录组学、诱变和模型菌株的实验方法来解决。这项工作旨在推动该领域的发展，使微生物铁循环的概念模型能够与海洋细菌有机碳循环的现有概念模型相结合。此外，本文提出的功能基因组学方法将确定和验证海洋中铁和碳循环之间联系的元组学、元蛋白质组学和生物信息学研究的目标，从而更好地对现有和计划中的大规模海洋数据集（如Tara Oceans、GEOTRACES和BioGeoSCAPES）进行调查。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

As a scarce but essential micronutrient for microbial growth in the marine environment, iron plays a critical role in supporting marine primary productivity and is tightly coupled to the cycling of carbon and other nutrients. Significant progress in recent years has been made in understanding the distribution of iron in the oceans and the impact of iron limitation on phytoplankton. Many questions remain, however, about the extensive biogeochemical linkages that exist between iron and carbon in marine systems. Bacteria represent a crucial and understudied node in this network. The proposed work will explore linkages between the carbon and iron cycles in marine systems in the context of the heterotrophic bacteria that are the primary drivers of the turnover of organic matter in the oceans. The project will support a postdoctoral researcher, as well as undergraduate interns. UCSD Bioengineering Senior Design Thesis students will be entrained to develop projects related to synthetic biology. The team will also host a 3-day workshop, in collaboration with Scripps Educational Alliances and the San Diego County Office of Education (SDCOE), to develop Next Generation Science Standards and CA Science Framework-aligned activities and resources for high school teachers in California. Educational activities will be based on “phenomena” associated with the proposed research, and after appropriate testing and refinement by local science teachers, will be broadly disseminated by the SDCOE. A functional genomics approach will be employed, using model organisms that have been shown to represent a spectrum in terms of their carbon substrate utilization and lifestyle strategies. Alteromonas spp., with numerous TonB-dependent outer membrane receptors and hydrolytic enzyme capabilities, are known for their ability to degrade and assimilate complex (i.e. high molecular weight) marine dissolved organic matter. In contrast, well-studied Roseobacters, with large numbers of inner-membrane transporters, specialize in the transport of low- molecular-weight organic matter. This project asks fundamental questions about how iron substrate utilization and iron-related physiology contribute to the known niche specificity of these organisms and impact carbon processing. These questions will be addressed through a combination of transcriptomic, mutagenic and experimental approaches with model strains. This work aims to advance the field so that conceptual models of microbial iron recycling can be integrated with current conceptual models of organic carbon recycling by marine bacteria. In addition, the functional genomics approach proposed here will identify and validate targets for meta-omic, meta- proteomic, and bioinformatic investigations of the links between iron and carbon cycling in the ocean, enabling better interrogation of existing and planned large-scale ocean datasets such as Tara Oceans, GEOTRACES, and BioGeoSCAPES.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.