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

人们越来越认识到，海洋中的物种拥有一组不同的微生物，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它们功能的理解。海洋中的初级生产者显示出丰富的微生物群落，并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，这是东北太平洋海岸的基本物种，牛海带Nerecystis luetkeana。这项研究探索了一组不同的微生物在牛海带中的作用。使用从海带中新分离的微生物分类群的实验操作，进行相互作用是正、负还是中性的测试。进行了微生物是否提供维生素和增加获得营养的具体分析，以及海藻分泌物是否有利于微生物新陈代谢和生长的测试。通过实习计划直接与部落青年合作，以及与本科生、学士研究生和研究生合作，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理解海藻衰退的努力提供了信息。宿主-微生物的相互作用是海洋物种持久性的一个组成部分，这项研究揭示了这些关系背后的因素。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“全息生物群”，它们的命运与它们所寄生的微生物息息相关。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。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，包括海洋变暖等宿主健康压力因素如何改变这些相互作用。追踪稳定氮同位素的实验以及与宿主和细菌分离株的操作被用来调查可能的交换和潜在的相互作用。代谢学、蛋白质组和基因组分析被用来量化宿主-微生物的相互作用以及分类群与它们的功能之间的联系。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物种的反应等。当宿主受到压力时，海洋中宿主-微生物相互作用的变化表明，这项研究的发现适用于理解促进真核-原核生物伙伴关系持续的因素。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.