Impact of soil microaggregate characteristics on microbial colonization patterns

土壤微团聚体特性对微生物定殖模式的影响

• 批准号: 276973576
• 负责人: Professorin Dr. Claudia Knief
• 金额: --
• 依托单位: Arbeitsgruppe Molekularbiologie der Rhizosphäre
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/276973576?language=en
• 关键词: Impact; soil; microaggregate; characteristics; microbial

The proposed research unit FOR2179 aims at an in-depth understanding of the process of soil microaggregate formation and microaggregate stability in relation to its chemical composition and microarchitecture, and the role of microaggregates for soil functioning, including the habitat function for microorganisms. Microaggregates and clay particles represent a major habitat for bacteria in soil. The arrangement and aggregation of soil components to a three dimensional structure is thus among the controlling factors of biological processes. Microorganisms contribute to the formation, stability and destabilization of soil microaggregates. The work proposed within this subproject covers both aspects, the habitat function of microaggregates for bacteria and the role of bacteria in microaggregate formation and stability. We will prove the hypothesis that different types of microaggregates, obtained from a soil toposequence of variable clay content, host different types of bacterial communities and that this selection is influenced by the physicochemical characteristics of the microaggregates. To this end, bacterial community composition and diversity will be analysed in fractionated microaggregates using molecular methods. The obtained data that describe the microbial communities will be analysed in combination with those that describe the physicochemical parameters of the microaggregates, which will be provided by different partners of this research unit, to identify those factors that exert an effect on bacterial colonization. A second major aim of this subproject will be the study of the localization of metabolically active cells, whereby different bacterial taxa are expected to be active in spatially restricted specific microsites of microaggregates. The characteristics of these microsites will be analysed at micrometre scale and thus single-cell-level, based on fluorescent microscopy in combination with mass spectrometric methods such as LA-IRMS, LA-ICP-MS and nanoSIMS. The habitats of active and inactive cells will be compared to identify possible controls of microbial activity in and on microaggregates. To assess the role of bacteria for aggregate formation, we will focus on selected model organisms in this first phase of the project and perform aggregation experiments to identify to what extent different bacteria contribute to aggregate formation and stabilization. Microbial destabilization of microaggregates will be analysed by studying the degradation of labelled extracellular polymeric substances, which serve as stabilizing organic material in a central microcosm experiment. With these different approaches, we will obtain data that allow to obtain a deeper understanding regarding the question how microorganisms affect microaggregate formation and their disaggregation on the one hand and the regulatory mechanisms of microaggregates on microbial presence and activity on the other hand.

拟议的研究单元FOR 2179旨在深入了解土壤微团聚体形成和微团聚体稳定性的过程，以及微团聚体对土壤功能的作用，包括微生物的栖息地功能。微团聚体和粘土颗粒是土壤中细菌的主要栖息地。因此，土壤组分的排列和聚集成三维结构是生物过程的控制因素之一。微生物有助于土壤微团聚体的形成、稳定和不稳定。在这个子项目中提出的工作包括两个方面，微团聚体的细菌的栖息地功能和微团聚体的形成和稳定性中的细菌的作用。我们将证明这一假设，不同类型的微团聚体，从可变的粘土含量的土壤toposequence，主机不同类型的细菌群落，这种选择的影响的微团聚体的理化特性。为此，将使用分子方法在分级微聚集体中分析细菌群落组成和多样性。所获得的描述微生物群落的数据将与描述微聚集体的理化参数的数据结合进行分析，这些参数将由本研究单位的不同合作伙伴提供，以确定对细菌定植产生影响的因素。这个子项目的第二个主要目标将是研究代谢活性细胞的定位，从而不同的细菌类群有望在微聚集体的空间受限的特定微位点中发挥作用。这些微点的特征将在微米尺度上进行分析，从而在单细胞水平上进行分析，基于荧光显微镜结合质谱方法，如LA-IRMS，LA-ICP-MS和nanoSIMS。将比较活性和非活性细胞的生境，以确定微团聚体中和微团聚体上微生物活性的可能控制因素。为了评估细菌在聚集体形成中的作用，我们将在项目的第一阶段重点研究选定的模式生物，并进行聚集实验，以确定不同细菌对聚集体形成和稳定的贡献程度。微团聚体的微生物不稳定性将通过研究标记的细胞外聚合物的降解来分析，这些聚合物在中央微观实验中充当稳定有机材料。通过这些不同的方法，我们将获得数据，使微生物如何影响微聚集体的形成和解聚的问题，一方面和微聚集体对微生物的存在和活性的调节机制，另一方面获得更深入的了解。