Endophytic Nitrogen Fixation by European Beachgrass (Ammophila Arenaria)

欧洲海滩草（Ammophila Arenaria）的内生固氮作用

• 批准号: 9816583
• 负责人: David Dalton
• 金额: $ 7万
• 依托单位: Reed College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2001-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9816583&HistoricalAwards=false
• 关键词: Endophytic; Nitrogen; Fixation; European; Beachgrass

Some grasses appear to be able to obtain fixed nitrogen throughsymbiotic relations with various bacteria. This project deals with a newsymbiosis involving European beachgrass (Ammophila arenaria) andnitrogen-fixing bacteria living within the shoots and rhizomes of the hostplant. The primary objective is to determine the extent of nitrogenfixation (acetylene reduction) activity in this grass in order to confirmif the rates are significant. Additional objectives are to characterizethe microorganisms involved in the Ammophila symbiosis, to determine thenatural abundance and distribution of these microorganisms, and todetermine if a similar symbiosis might be present in or introduced intoother species of grasses (including crop species). Inoculated and axenicseedlings will be used in greenhouse and field trials to determine ifAmmophila benefits from its bacterial symbiont. The rates of nitrogenfixation in the field and the effects of environmental variables will bemeasured by acetylene reduction assays. The precise location ofendophytic bacteria will be determined using immunological techniques atboth the light and electron microscope level with existing antibodies.The bacteria will be characterized with regards to the genes involved withnitrogen fixation and the effects of oxygen and fixed nitrogen on nitrogenfixation. Other species of grasses will also be examined for similarsymbioses using acetylene reduction assays and immunolocalization by lightmicroscopy. The Ammophila symbiosis is promising in that it involvesnovel bacterial symbionts with unknown properties and host ranges in atype of symbiosis previously thought to be largely if not entirelyrestricted to tropical grasses. In addition to providing insight into thephenomenal success of Ammophila on bare sand, these studies might openossibilities for endophytic nitrogen fixation by grasses of agriculturalsignificance.

有些草似乎能通过与各种细菌的共生关系获得固定氮。 本项目涉及一种新的共生关系，涉及欧洲滨草（Ammophila arenaria）和生活在寄主植物的芽和根茎中的固氮细菌。 主要目的是确定固氮（乙炔还原）活动在这种草的程度，以确认率是否显着。 另外的目的是表征参与Ammophila共生的微生物，以确定这些微生物的自然丰度和分布，并确定类似的共生是否可能存在于或引入到其他草类（包括作物物种）中。 接种和无菌苗将用于温室和田间试验，以确定是否Ammophila受益于其细菌共生体。 田间固氮速率和环境变量的影响将通过乙炔还原测定来测量。 利用免疫学技术，在光镜和电镜水平上，利用现有的抗体，确定内生细菌的精确位置。细菌的特征在于与固氮有关的基因以及氧和固定氮对固氮的影响。 其他种类的草也将检查类似的共生体使用乙炔还原测定和免疫定位的光学显微镜。 Ammophila共生是有希望的，因为它涉及新的细菌共生体，这些共生体具有未知的特性和宿主范围，以前认为这种共生体主要（如果不是全部）限于热带草。 这些研究除了提供了对Ammophila在裸沙上的惊人成功的深入了解外，还可能为具有农业意义的禾本科植物的内生固氮开辟道路。