Microbial Observatories: Diversity of Plant-Associated Diazotrophic Bacteria and Their Distributions Within Specific Vegetation Zones Along an Environmental Gradient

一笔赠款已授予查尔斯·R博士。南卡罗来纳州大学（USC）的Lovell和Madilyn弗莱彻研究了一组称为固氮生物的微生物。 这些生物-也称为固氮细菌-通过从大气中捕获氮气并将其转化为可供其他微生物，植物和动物使用的形式，在营养循环中发挥独特的作用。 由于氮是所有生命系统的必需营养素，固氮生物的活动是这个星球上生命的基础。 固氮生物种类繁多，许多与植物的根部有关。 其中大多数的特征不明显，还有更多的尚未被发现。 在这项工作中，固氮生物与盐沼植物的特点，以确定特定类型的固氮生物，在环境因素的变化，和不同的宿主植物之间的关系。 将鉴定固氮生物，并利用现代遗传技术评估其固氮活性。 将使用分子探针和先进的显微镜方法来确定它们与特定类型的植物根的关联。 通过这种方式，将有可能识别新的固氮微生物，评估它们与植物关系的特异性，并确定它们随时间和空间的丰度和活性。由于固氮生物能够固定大气中的氮，因此可以提高自然和农业系统的生产力。 控制氮的可用性和盐沼系统的生产力的因素有重要的影响，一系列的恢复和保护工作。 此外，了解固氮植物的关系和发现新的固氮生物可能会应用于农业和作物系统，这取决于土壤中的氮水平。 该项目将通过提供研究生实习机会并与巴鲁克海洋野外实验室（BMFL）的国家河口研究储备对接，对学生培训产生直接影响。 该项目还将加强位于EPSCoR州的BMFL和南加州大学的研究设施和培训活动。

A grant has been awarded to Drs. Charles R. Lovell and Madilyn Fletcher of the University of South Carolina (USC) to investigate a group of microorganisms called diazotrophs. These organisms - also called nitrogen-fixing bacteria - play a unique role in nutrient cycling by capturing nitrogen gas from the atmosphere and converting it into forms that can be used by other microorganisms, plants, and animals. Since nitrogen is an essential nutrient for all living systems, the activity of diazotrophs is fundamental to life on this planet. Diazotrophs are extremely diverse, and many are associated with the roots of plants. Most are poorly characterized, while still more remain undiscovered. In this work, diazotrophs associated with salt marsh plants will be characterized to determine the relationships between specific types of diazotrophs, variations in environmental factors, and different host plants. The diazotrophs will be identified and their nitrogen-fixing activity will be assessed using modern genetic techniques. Their association with specific types of plant roots will be determined using molecular probes and advanced microscopy methods. In this way, it will be possible to identify new diazotrophic microorganisms, assess the specificity of their relationships with plants, and determine their abundance and activity over time and space. Because of their ability to fix atmospheric nitrogen, diazotrophs can enhance the productivity of both natural and agricultural systems. The factors that control nitrogen availability and the productivity of salt marsh systems have important implications for a range of restoration and conservation efforts. Moreover, an understanding of diazotroph-plant relationships and the discovery of new diazotrophs may have applications to agricultural and crop systems, which depend on nitrogen levels in soils. This project will have a direct impact on student training through providing graduate student internships and interfacing with the National Estuarine Research Reserve based at the Baruch Marine Field Laboratory (BMFL). The project will also enhance research facilities and training activities at the BMFL and USC, which are located in an EPSCoR state.