The implications of micro-habitat architecture for soil microbial community structure and function

土壤健康是指土壤维持生命的能力。这是一个具有重大科学和社会意义的话题。健康的土壤中有大量微小的有益微生物，它们可以获取和循环生命的基本组成部分，包括营养物质和碳，并使它们可供下一代植物使用。有益的土壤微生物与植物形成复杂的关系，支持作物生长和生产力。尽管它们构成了地球上生物多样性最丰富的群落，但关于微生物帮助保持土壤健康和促进植物生长的方式的许多细节仍然是个谜。例如，微生物群落如何应对水和土壤化学成分的变化，这些变化可能在很小的距离内发生巨大变化？该研究项目将使用最先进的方法和最近开发的x射线技术来检查土壤的微观性质，包括土壤孔隙的数量和大小、pH值、营养和碳的质量和有效性。这些测量将与高通量基因组测序相结合，以检查这些特性对微生物多样性和土壤健康的影响。该项目将通过推进有关微生物在支持土壤健康、粮食安全和农业方面所起作用的基本知识，为国家利益服务。该项目还将推动土壤生态系统科学领域的发展，并通过为本科生提供真实的实验室研究机会，支持教育和劳动力培训。通过剖析精确的物理和化学微环境变量及其相关微生物的结构和功能，探讨土壤微生境空间异质性与微生物多样性之间的关系。该研究将确定微生物（细菌和古细菌）与微环境变量之间的关联，作为土壤与植物关联的功能（特别是根际与散装土壤中植物来源碳的微尺度分布）；并确定微环境特征负责不同的微生境适合某些微生物群。该研究提供了一种全新的方法，将基于同步加速器的x射线计算机微断层扫描信息与微生物宏基因组学相结合，以更好地理解物理微环境条件在决定土壤微生物群落组成和功能多样性方面所起的作用。本研究将率先对微生物功能的关键要素进行定量、综合分析，包括土壤孔隙的结构和特征，它们与微生物结构中的微生物地理格局的关系，以及与植物根系相关的空间微生物地理格局。该项目的一个独特特点是，观察到的微生境空间格局将具体参照土壤孔隙的当地特征（“地理参照”）进行研究，土壤孔隙是空气、水和养分流动以及土壤微生物迁移的途径。更广泛的影响将包括对农业、林业和粮食安全的潜在好处，以及通过实习进行多学科本科生研究培训。

Soil health refers to the capacity of soil to sustain life. It is a topic of great scientific and societal importance. Healthy soils have hordes of tiny, beneficial microorganisms that access and recycle the building blocks of life, including nutrients and carbon, and make them available to the next generation of plants. Beneficial soil microorganisms form intricate relationships with plants, supporting crop growth and productivity. Although they comprise some of the most biologically diverse communities on Earth, many details regarding the ways which microorganisms help maintain soil health and promote plant growth remain mysterious. For example, how do microbial communities cope with variations in the water and chemical content of soil, which can change drastically over small distances? This research project will use state-of-the-art methods and recently developed x-ray technology to examine soil micro-scale properties including the number and size of soil pores, pH, and nutrient and carbon quality and availability. These measurements will be coupled with high through-put genome sequencing to examine the impact of these properties on microbial diversity and soil health. This project will serve national interests through advancing fundamental knowledge about the roles that microorganisms play to support soil health, food security and agriculture. The project will also advance the field of soil ecosystem science, and will support education and workforce training through authentic laboratory research opportunities for undergraduates.The relationship between spatial heterogeneity of soil micro-habitats and microbial diversity will be investigated by dissecting precise physical and chemical micro-environmental variables and the structure and function of their associated microorganisms. The research will determine associations between microorganisms (bacteria and archaea) and micro-environmental variables as a function of soil associations with plants (specifically the microscale distribution of plant-derived carbon in rhizosphere versus bulk soils); and identify the micro-environmental characteristics responsible for suitability of distinct micro-habitats to certain microbial groups. This research offers a fundamentally new approach of combining synchrotron-based X-ray computed micro-tomography information with microbial metagenomics to achieve an improved understanding of the role that physical micro-environmental conditions play in determining compositional and functional diversity of soil microbial communities. This study will pioneer quantitative, combined analysis of key elements important for microbial functioning, including the architecture and characteristics of soil pores, their relationship to micro-biogeographic patterns in microbial structure, and spatial micro-biogeographic patterns that emerge given associations with plant roots. One unique feature of the project is that observed spatial patterns of micro-habitats will be studied with specific reference to local characteristics of soil pores ("geo-referencing"), which are the avenues enabling air, water, and nutrient fluxes and soil microbial migration. Broader impacts will include potential benefits to agriculture, forestry and food security, as well as multidisciplinary undergraduate research training via internships.