The role of microbes in driving productivity and carbon fixation in seaweeds

人们越来越认识到，海洋中的物种拥有各种各样的微生物，这些微生物可以决定宿主的功能。然而，自然界中微生物类群的发现远远超过了我们对其功能的理解。海洋中的初级生产者显示出丰富的微生物群落，可能有助于大型植物在沿海社区中发挥重要作用。该项目的重点是一种冠层海带，这是一个基本的物种沿着海岸的东北太平洋，公牛海带Nereocystis luetkeana。这项研究探讨了与巨藻相关的各种微生物的作用。使用实验操作新分离的微生物类群海带，测试是否相互作用是积极的，消极的，或中性的。进行了微生物是否提供维生素和增强营养物质获取的具体分析，以及海带分泌物是否有利于微生物代谢和生长的测试。通过实习计划直接与部落青年以及本科生，学士后和研究生合作，有助于培养下一代海洋科学家。与部落和州政府的沟通渠道为了解海带减少的努力提供了信息。宿主-微生物相互作用是海洋物种持久性的一个组成部分，这项研究为这些关系的基础因素提供了信息。DNA测序、成像和其他分子方法的出现揭示了海洋中的许多关键物种是一个“全息生物组”，它们的命运与它们所宿主的微生物密不可分。然而，自然界中微生物类群的发现远远超过了我们对微生物功能的理解。卢特基纳囊藻（Nereocystis luetkeana）或公牛海带，以及研究人员从海带表面分离出的细菌，提供了一个量化宿主-微生物相互作用的机会，包括宿主健康的压力因素（如海洋变暖）如何改变这些相互作用。追踪稳定氮同位素的实验和对宿主和细菌分离株的操纵被用来研究可能的交换和相互作用的货币。代谢组学、蛋白质组学和基因组学分析用于量化宿主-微生物相互作用以及分类群与其功能之间的联系。正在研究的关键微生物代谢包括营养供应、维生素合成和对活性氧的反应等。当宿主受到压力时，海洋中宿主-微生物相互作用的改变表明本研究的结果可用于理解促进真核生物-原核生物伙伴关系持久性的因素。该奖项反映了NSF的法定使命，并被认为值得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来支持。

It is increasingly recognized that species in the ocean host a diverse set of microbes and that these microbes can determine the functioning of the host. Yet, the discovery of microbial taxa in nature far outpaces our understanding of their functions. Primary producers in the ocean show rich microbial communities and may contribute to the significant role that macrophytes play in coastal communities. This project focuses on a species of canopy kelp that is a foundational species along the shores of the northeast Pacific Ocean, the bull kelp Nereocystis luetkeana. The research explores the role of a diverse set of microbes in association with bull kelp. Using experimental manipulations of newly isolated microbial taxa from kelp, tests of whether interactions are positive, negative, or neutral are performed. Specific assays of whether microbes provision vitamins and enhance access to nutrients are carried out, as well as tests of whether kelp exudates benefit microbial metabolism and growth. Working directly with Tribal youth through an internship program, as well as with undergraduate, post-baccalaureate, and graduate students, helps train the next generation of ocean scientists. Communication channels with Tribal and State governments inform efforts to understand kelp declines. Host-microbe interactions are a component of the persistence of ocean species and this research informs the factors that underly these relationships. The advent of DNA sequencing, imaging, and other molecular approaches have revealed that many key species in the ocean are a ‘holobiome’, and their fate is entwined with the microbes they host. Yet, this discovery of microbial taxa in nature far outpaces our understanding of microbial function. Nereocystis luetkeana, or bull kelp, and the bacteria the investigators have isolated from the kelp surface, present an opportunity to quantify host-microbe interactions, including how stressors of host health, such as ocean warming, alter these interactions. Experiments tracing stable nitrogen isotopes and manipulations with hosts and bacterial isolates are used to investigate possible exchanges and the currencies underlying interactions. Metabolomic, proteomic, and genomic analyses are used to quantify host-microbe interactions and linkage between taxa and their functions. Key microbial metabolisms being investigated include nutrient provisioning, vitamin synthesis, and the response to reactive oxygen species, among others. The demonstrated alteration of host-microbe interactions in the ocean when hosts are stressed suggest the findings of this study have application to understanding the factors that promote persistence of eukaryote-prokaryote partnerships.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.