Dimensions: Taxonomic, genetic and functional biodiversity of above-ground bacterial endophytes in subalpine conifers

维度：亚高山针叶树地上细菌内生菌的分类、遗传和功能生物多样性

• 批准号: 1442348
• 负责人: Anna Carolin Frank
• 金额: $ 162.39万
• 依托单位: University of California - Merced
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1442348&HistoricalAwards=false
• 关键词: Dimensions; Taxonomic; genetic; functional; biodiversity

Nitrogen (N) is essential to all life on Earth, but only select microbes can reduce or 'fix' N to a form that plants can use. Typically, plants can only use atmospheric N can when fixed by microbes that live in the soil or via a symbiotic relationship with legumes, but recent findings indicate that bacteria inside pine needles can also perform this critical function. In this research, investigators at University of California, Merced will examine the symbiosis between bacteria and limber pine (Pinus flexilis). The goals are to understand the diversity of bacteria present in pine needles, calculate how much N microbes fix and under what conditions, and infer how this fixed N is transferred to the tree. The research could significantly improve our understanding of the N cycle and help identify a currently unknown source of fixed N within coniferous forests. A more complete understanding of the N cycle will also help improve climate models, and a better characterization of the microbes that can fix Nitrogen could lead to advances in crop development. This research will train undergraduates. graduate students and post-doctoral researchers in both field and lab techniques. Additionally, the research will include outreach to teachers, administrators and students at a K-8 STEM school serving under-represented groups, and will develop inquiry-based learning modules in line with Common Core educational standards for incorporation within the K-8 STEM curriculum.The investigators will examine how the phylogenetic diversity and genetic potential of subalpine tree endophytes affect N fixation within western coniferous forests. Their central hypothesis is that across its broad geographic range, limber pine hosts a broad taxonomic, genetic and functional biodiversity of mutualistic N fixing endophytes, shaped by the local environment, and shared, in part, with neighboring trees. To test this, investigators will examine the biodiversity of endophytes in limber pine and co-occurring species across the limber pine range, identify the factors that structure the patterns of diversity, and determine the relationship between taxonomic diversity and N fixation. Cutting-edge methods in sequencing and genome analysis will be integrated with established and highly sensitive methods for detecting and visualizing N fixing activity in situ to understand how endophyte diversity is shaped by the environment and shapes the N cycle in subalpine forests.

氮(N)对地球上的所有生命都是必不可少的，但只有精选的微生物才能将氮减少或“固定”为植物可以利用的形式。通常情况下，植物只有在被生活在土壤中的微生物固定或通过与豆科植物的共生关系固定时才能利用大气中的氮，但最近的发现表明，松针内的细菌也可以发挥这一关键功能。在这项研究中，加州大学默塞德分校的研究人员将研究细菌与软松木（松）之间的共生关系。目标是了解松针中存在的细菌多样性，计算微生物在什么条件下固定了多少N，并推断这些固定的N是如何转移到树上的。这项研究可以显著提高我们对氮循环的理解，并有助于确定针叶林中目前未知的固定氮来源。更全面地了解氮循环也将有助于改善气候模型，更好地描述能够固定氮的微生物可能会导致作物发育的进步。这项研究将培养本科生。现场和实验室技术的研究生和博士后研究人员。此外，这项研究将包括向一所服务于代表性不足群体的K-8 STEM学校的教师、管理人员和学生进行推广，并将开发符合共同核心教育标准的探究式学习模块，以纳入K-8 STEM课程。研究人员将研究亚高山树木内生植物的系统发育多样性和遗传潜力如何影响西部针叶林的固氮作用。他们的中心假设是，在其广阔的地理范围内，松木拥有广泛的分类、遗传和功能多样性，由当地环境塑造，并在一定程度上与邻近的树木共享。为了验证这一点，研究人员将研究整个针叶松林及其共生物种的内生菌多样性，确定构成多样性模式的因素，并确定分类多样性与固氮之间的关系。测序和基因组分析的前沿方法将与现有的高灵敏度方法相结合，用于原位检测和可视化氮固定活性，以了解亚高山森林内生菌多样性如何受到环境的影响，以及如何影响N循环。