Dissertation Research: Local adaptation and gene flow: The legume-rhizobia mutualism and edaphic heterogeneity

论文研究：局部适应和基因流动：豆科植物-根瘤菌互利共生和土壤异质性

• 批准号: 0909154
• 负责人: Kevin Rice
• 金额: $ 1.5万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0909154&HistoricalAwards=false
• 关键词: Dissertation; Research; Local; adaptation; gene

While the negative effects of bacteria on larger organisms are familiar, more mysterious are the multitudes of positive effects they can have on their hosts. One model case is the benefit leguminous plants, like beans and clovers, receive from nitrogen-fixing bacteria called rhizobia that live in the plant's roots. Plants trade energy-rich photosynthetic sugars to bacteria housed in root nodules for bacterially-obtained nitrogen, a limiting nutrient for plant growth. This symbiosis has proven to be a highly effective strategy, and legumes can persist in a wide variety of habitats. The performance of a legume in any particular environment can depend on how well adapted both the plant and rhizobia are to the particular aspects of a site, since both partners are highly interdependent. However, very little is known about the relative importance of host plant versus rhizobia adaptations to the survival of either partner. This project addresses how interactions between a native and an invasive legume and their rhizobial partners differ on and off serpentine outcrops. These outcrops harbor remnant pockets of California's native floral diversity, protected from most invasive plants by harsh soil conditions. Native or invasive legumes may be able to adapt to this harsh environment without the aid of specific rhizobia, or they may depend on having symbionts that are specialized for that particular environment. Understanding the nature of legume-rhizobia symbioses on and off serpentine soils is an essential first step toward managing and conserving these threatened plant communities. Undergraduate students will be involved in this research, and results will be made public via an existing webpage.

虽然细菌对大型生物体的负面影响是众所周知的，但更神秘的是它们对宿主的众多积极影响。一个典型的例子是豆科植物，如豆类和三叶草，从植物根部被称为根瘤菌的固氮细菌中获益。植物用富含能量的光合作用糖与根瘤中的细菌交换细菌获得的氮，氮是植物生长的限制性营养物质。这种共生关系已被证明是一种非常有效的策略，豆科植物可以在各种各样的栖息地中生存。豆科植物在任何特定环境中的表现可能取决于植物和根瘤菌对场地特定方面的适应程度，因为两者是高度相互依赖的。然而，对于寄主植物和根瘤菌适应对任何伴侣生存的相对重要性知之甚少。该项目解决了本地和入侵豆科植物及其根瘤菌伙伴在蛇纹石露头上和露头下的相互作用。这些露出地面的地方保存着加利福尼亚本土植物多样性的残余，恶劣的土壤条件保护着它们不受大多数入侵植物的侵害。原生或入侵的豆科植物可能能够在没有特定根瘤菌的帮助下适应这种恶劣的环境，或者它们可能依赖于特定环境的共生体。了解豆科植物-根瘤菌在蛇纹石土壤上和土壤外共生的性质是管理和保护这些受威胁植物群落的重要的第一步。本科生将参与这项研究，结果将通过现有的网页公布。