Enzymatic diversity of biological nitrogen fixation: above, below and beyond cyanolichens.

生物固氮酶的多样性：高于、低于和超越氰基地衣。

• 批准号: RGPIN-2022-04039
• 负责人: Bellenger, JeanPhilippe
• 金额: $ 3.72万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=748653
• 关键词: Enzymatic; diversity; biological; nitrogen; fixation

Context - Biological nitrogen fixation (BNF) is a key reaction of the N cycle and an important source of new N to unmanaged ecosystems. This reaction is catalyzed by three isoforms, the molybdenum-based nitrogenase, and two complementary nitrogenases (comp-Nases); the vanadium based nitrogenase and the iron-only nitrogenase. Better evaluating which nitrogenases contribute to biological nitrogenase fixation has important implications for the estimation of N inputs and our understanding of the link between trace metal dynamics and BNF. Objectives - The long-term objective (10-15 years) of my research program is to decipher the link between trace metal dynamics and nitrogen cycling. My short term objective (next 5 years) is the decipher the occurrence and contribution of comp-Nases to BNF at the earth scale. To achieve this goal, over the next 5 years my research program aims at (1) evaluating the contribution of comp-Nases to boreal feather moss BNF, (2) assessing the presence and contribution of comp-Nases to BNF associated with higher plants matrices (phyllosphere and rhizosphere), (3) investigating the role of temperature, and its interaction with Mo availability, on the use of comp-Nases, (4) investigating the contribution of comp-Nases at the earth scale, (5) estimating how Mo of anthropogenic origin altered Nases use (Mo-Nase versus comp-Nases). Methodology - This research program includes both field and laboratory experiments. It will rely on a series of analytical tools for elemental analysis in biological matrices, molecular biology for the characterization of nitrogenase genes presence and expression and N2 fixing community, and analytical chemistry for the evaluation of BNF. Impact - This research program will contribute to close multiple knowledge gaps regarding the role of comp-Nases to BNF and the environmental drivers controlling their use. Deciphering the occurrence and contribution of comp-Nases to BNF at the ecosystem and earth scale is potentially transformative as it deeply affects the way we comprehend and estimate BNF in the field. For instance, most N input estimates derives from uncalibrated acetylene reduction assay which is highly nitrogenase isoforms dependent. If comp-Nases are more important than previously believed a profound reassessment of N input estimates will be required. It also questions our understanding of metals control over major nutrient cycling (i.e., N). Vanadium is likely a critical biometal for the biosphere which biogeochemical cycling and interactions with microorganisms remains poorly characterized, in comparison to its molybdenum counterpart. Because N input estimates are used for multiple purposes, this research will ultimately help end-users (e.g., forestry) and decision makers to improve Canadian natural resources management policies and practices.

生物固氮（BNF）是氮循环的一个关键反应，也是向未受管理的生态系统提供新氮的重要来源。该反应由三种同工异构体、钼基氮酶和两种互补氮酶（comp-Nases）催化；钒基氮酶和纯铁氮酶。更好地评估哪些固氮酶对生物固氮酶有贡献，对于估算N输入和理解微量金属动力学与生物固氮酶之间的联系具有重要意义。我的研究计划的长期目标（10-15年）是破译微量金属动力学和氮循环之间的联系。我的短期目标（未来5年）是在地球尺度上破译compo - nases对BNF的发生和贡献。为了实现这一目标，在接下来的5年里，我的研究计划旨在(1)评估compo - nases对北方羽毛苔藓BNF的贡献，(2)评估与高等植物基质（层际和根际）相关的compo - nases对BNF的存在和贡献，(3)研究温度及其与Mo有效性的相互作用对compo - nases利用的作用，(4)研究compo - nases在地球尺度上的贡献。(5)估计人为来源的Mo如何改变nase的使用（Mo- nase vs . comp- nase）。方法论-本研究项目包括现场和实验室实验。它将依靠一系列的分析工具来进行生物基质的元素分析，分子生物学来表征氮酶基因的存在和表达以及N2固定群落，分析化学来评估BNF。影响-该研究项目将有助于填补有关复合酶对生物燃料的作用和控制其使用的环境驱动因素的多个知识空白。在生态系统和地球尺度上破译生物多样性对生物多样性的发生和贡献具有潜在的变革性，因为它深刻影响了我们在野外理解和估计生物多样性的方式。例如，大多数氮输入估计来自未校准的乙炔还原测定，这是高度依赖于氮酶同工型的。如果对比比以前认为的更重要，就需要对N个投入估算进行深刻的重新评估。它也质疑我们对金属控制主要养分循环（即N）的理解。与钼相比，钒可能是生物圈中生物地球化学循环和与微生物相互作用的关键生物金属。由于N投入估算用于多种目的，本研究最终将帮助最终用户（例如林业）和决策者改进加拿大自然资源管理政策和做法。