From single pioneers to complex communities: Simultaneous discrimination of composition and inferring species interactions of fossil as well as modern pro- and eukaryotic microbial communities

从单一先驱到复杂群落：同时辨别化石以及现代亲核和真核微生物群落的组成并推断物种相互作用

• 批准号: 366085171
• 负责人: Professor Dr. Thomas Friedl
• 金额: --
• 依托单位: Abteilung Experimentelle Phykologie und Sammlung von Algenkulturen (EPSAG)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/366085171?language=en
• 关键词: single; pioneers; complex; communities; Simultaneous

Goal of the project is an understanding of the development of microbial communities in soil, from the initial assembly to complex networks. Microorganisms critically impact the development of soils in extreme environments. Soil microbes react with strong shifts in their community structures on environmental changes, e.g. nutrient increase or temperature raise. Antarctic soils are fragile ecosystems due to their low nutrient content; they are seen to provide very good early indications of environmental change. Our central working hypothesis includes that prokaryotic microorganisms are the key players in the initial assembly succeeding in a complex network of the various pro- and eukaryotic microorganisms which based on different functions within the network is responsible for the further development and, finally, the stabilization of the soil habitat. Eukaryotic algae may interact as pioneers already in the early stages of soil development given the bioavailability of nitrogen sources. To test the hypotheses the project will link the expertise of Göttingen University and GFZ Potsdam. We will utilize already available samples collected at five transects in the forefields of glacier remains in ice-free oases at Larsemann Hills, Prydz Bay, East Antarctica. A thorough analysis of key physicochemical parameters of the soil samples is crucial to relate microbial diversity to geochemical variables. Given the extreme oligotrophic environment and remoteness of the study sites we expect to recover a considerable number of well adapted so far unknown species, representing a valuable source for potential biotechnological applications. We extend the space-for-time substitution approach of chronosequences to the microscale of comparisons between extracellular and intracellular DNA of microrganisms. Performing of a novel DNA extraction protocol will enable a precise distinction between extinct (fossil) and recent live microbial communities. Both DNA pools will serve the taxonomic assessment of microbial communities at the level of species. Finally, through deep sequencing (Illumina MiSeq) of amplicons from two complementary and differently variable rRNA gene signatures resolution at the species level will be accomplished. This is essential to infer those species interactions at high precision which facilitate the development of early soil ecosystems, i.e. within microbial associations across kingdoms and domains, e.g. between eukaryotic algae and bacteria. Analyses of functional genes will assess structure and functional relationships between pro- and eukaryotic microbial communities in nutrient fluxes of carbon and nitrogen. Finally, after estimating the relative abundances of the distinct microbial and functional groups using quantitative qPCR those species interactions can be inferred which act on the microbial production.

该项目的目标是了解土壤中微生物群落的发展，从最初的组装到复杂的网络。微生物对极端环境中土壤的发育有着至关重要的影响。土壤微生物对环境变化（如养分增加或温度升高）的反应是其群落结构发生强烈变化。南极土壤是脆弱的生态系统，因为其营养含量低;它们被认为是环境变化的良好早期迹象。我们的中心工作假设包括，原核微生物是在初始组装成功的各种亲和真核微生物的复杂网络的基础上，网络内的不同功能的主要参与者是负责进一步发展，并最终稳定的土壤生境。考虑到氮源的生物利用率，真核藻类可能在土壤发育的早期阶段就已经作为先驱者相互作用。为了检验这些假设，该项目将把哥廷根大学和德国出口合作中心波茨坦的专门知识结合起来。我们将利用已经收集的样品在五个断面的冰川仍然在无冰绿洲在拉斯曼山，Preniz湾，东南极洲的前田。土壤样品的关键理化参数的彻底分析是至关重要的微生物多样性与地球化学变量。鉴于极端贫营养环境和偏远的研究地点，我们预计将恢复相当数量的适应良好，迄今未知的物种，代表潜在的生物技术应用的宝贵来源。我们将时空置换方法扩展到微生物细胞外和细胞内DNA之间的微观比较。执行一个新的DNA提取方案将能够精确区分灭绝（化石）和最近的活微生物群落。这两个DNA库将用于在物种一级对微生物群落进行分类评估。最后，通过对来自两个互补且不同可变的rRNA基因签名的扩增子进行深度测序（Illumina MiSeq），将实现物种水平的解析。这对于以高精度推断那些促进早期土壤生态系统发展的物种相互作用是至关重要的，即在跨界和域的微生物协会内，例如真核藻类和细菌之间。功能基因的分析将评估亲和真核微生物群落之间的结构和功能关系的碳和氮的营养通量。最后，在使用定量qPCR估计不同微生物和官能团的相对丰度后，可以推断出作用于微生物生产的那些物种相互作用。