Abundance, diversity and niche-specific traits of ammonia oxidizers inhabiting soil temporarily flooded by seawater

暂时被海水淹没的土壤中氨氧化剂的丰度、多样性和生态位特征

• 批准号: 253075353
• 负责人: Dr. Heiko Nacke
• 金额: --
• 依托单位: Abteilung Genomische und Angewandte Mikrobiologie
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/253075353?language=en
• 关键词: Abundance; diversity; niche; specific; traits

Soil nitrification, a key process within numerous natural and agricultural ecosystems, can evoke groundwater pollution and significantly affects plant nutrition as well as greenhouse gas release. The initial and rate-limiting step of this globally important process, ammonia oxidation, is mediated by archaeal and bacterial soil microorganisms. In this project, the impact of seawater flooding frequency on abundance and diversity of these nitrifying prokaryotes, as well as genetic and physiological traits of ammonia oxidizing archaea present in frequently flooded soil, will be investigated. The analyses, comprising culture-based and culture-independent approaches, are carried out on the basis of top soil samples derived from the German Halligen Hooge, Langeness and Nordstrandischmoor. Flooding-related changes in abundance, taxonomic composition as well as species richness of archaeal and bacterial ammonia oxidizers are assessed by quantitative PCR and amplicon sequencing of amoA and 16S rRNA genes isolated from Hallig soil. In order to identify thaumarchaeal genomic characteristics potentially conferring selective advantages within soil frequently swamped by seawater (e.g., genes involved in protection against osmotic stress), construction and screening of complex metagenomic libraries will be performed. Moreover, culturing and growth experiments are conducted to isolate environmentally representative members of archaeal ammonia oxidizers from Hallig soil and to determine their physological adaptations toward frequent flooding. Physiology analyses include the investigation of microbial growth under varying salt, oxygen and ammonia concentrations as soils frequently flooded by sea water represent salty environments characterized by periods of low oxygen availability and nutrient washout. Considering that there is strong evidence for global sea level rise, wetlands occupy approximately 6% of the land area worldwide, and flooded soil environments are often used agriculturally, knowledge on functional microbial groups colonizing soil temporarily swamped by seawater is required to predict and control ecosystem functions within these habitats. The proposed project will contribute to an improved understanding of microbiota controlling nitrification within flooded soils by providing detailed information on quantity, diversity, and niche-specific traits of archaeal and bacterial ammonia oxidizers.

土壤硝化是众多自然和农业生态系统中的一个关键过程，会引起地下水污染，并严重影响植物营养和温室气体释放。这一全球重要过程的初始和限速步骤——氨氧化，是由古细菌和细菌土壤微生物介导的。在该项目中，将研究海水淹没频率对这些硝化原核生物的丰度和多样性的影响，以及频繁淹没土壤中存在的氨氧化古菌的遗传和生理特征。这些分析包括基于培养物和独立于培养物的方法，是在来自德国 Halligen Hooge、Langeness 和 Nordstrandischmoor 的表层土壤样本的基础上进行的。通过对从 Hallig 土壤中分离出的 amoA 和 16S rRNA 基因进行定量 PCR 和扩增子测序，评估了与洪水相关的古菌和细菌氨氧化剂的丰度、分类组成以及物种丰富度的变化。为了鉴定在经常被海水淹没的土壤中可能赋予选择优势的奇菌基因组特征（例如，涉及防止渗透胁迫的基因），将进行复杂宏基因组文库的构建和筛选。此外，还进行了培养和生长实验，以从哈利格土壤中分离出古菌氨氧化菌的环境代表性成员，并确定它们对频繁洪水的生理适应。生理学分析包括对不同盐、氧和氨浓度下微生物生长的研究，因为经常被海水淹没的土壤代表着以低氧利用率和养分流失为特征的咸环境。考虑到有强有力的证据表明全球海平面上升，湿地约占全球陆地面积的 6%，而且淹没的土壤环境经常用于农业，因此需要了解暂时被海水淹没的土壤中定殖的功能微生物群的知识，以预测和控制这些栖息地内的生态系统功能。拟议的项目将通过提供有关古菌和细菌氨氧化剂的数量、多样性和生态位特定特征的详细信息，有助于更好地了解淹没土壤中控制硝化作用的微生物群。