Suppression of rhizobial reproduction by legumes: Implications for mutualism

豆科植物对根瘤菌繁殖的抑制：对互利共生的影响

• 批准号: 0918986
• 负责人: Robert Ford Denison
• 金额: $ 26.22万
• 依托单位: University of Minnesota-Twin Cities
• 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: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0918986&HistoricalAwards=false
• 关键词: Suppression; rhizobial; reproduction; legumes; Implications

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Rhizobia are bacteria that can live in soil, but also symbiotically, inside root nodules on plants like soybean or alfalfa. Although many rhizobia provide their host plants with nitrogen, saving farmers billions in fertilizer costs, less beneficial strains cause problems in some areas. Some hosts, including alfalfa and pea, make rhizobia swell up as they start to provide nitrogen. Unlike the nonswollen rhizobia from soybean or cowpea nodules, swollen rhizobia apparently lose the ability to reproduce, but does rhizobial swelling somehow benefit the plant? To find out, the investigators will map this trait on the family tree for crops and wild plants that host rhizobia, to see if causing swelling evolved more than once, suggesting a positive benefit to the plants. Three dual-host rhizobia (plus mutants that differ in their ability to hoard resources) will be used to measure effects of rhizobial swelling on costs and benefits to the plants. Plant defenses against rhizobia that provide little or no nitrogen, already demonstrated in soybean, will be tested in species that impose bacterial swelling. This research will increase understanding of a symbiosis that supplies nitrogen to agricultural and natural ecosystems, with implications for other important symbioses. Results could guide the development of crops that selectively enrich soils with the best rhizobia, decreasing future fertilizer requirements. Educational opportunities will be provided for undergraduates, at least one graduate student, and a postdoctoral researcher. Two female high school students have already won trips to the International Science Fair for research done in the principal investigator's laboratory, where such mentoring will continue to be a priority.

该奖项是根据2009年的《美国复苏和再投资法》（公法111-5）资助的。Rhizobia是可以生活在土壤中但同样在大豆或苜蓿等植物上的根结节内的细菌。 尽管许多根瘤菌为其寄主植物提供氮，从而为农民节省了数十亿美元的肥料成本，但在某些地区，有益的菌株较少会引起问题。 包括苜蓿和豌豆在内的一些宿主在开始提供氮时会使根瘤菌膨胀。 与来自大豆或牛豆结节的非鼻状根瘤菌不同，根瘤菌显然失去了繁殖的能力，但是根茎肿胀是否使该植物受益？ 为了找出答案，研究人员将在家谱上绘制这种特征，用于托有根瘤菌的农作物和野生植物，以查看导致肿胀是否不止一次发展，这表明对植物有积极的好处。 将使用三个双宿主根瘤菌（加上其ho积资源能力不同的突变体）将用于衡量根茎肿胀对植物成本和收益的影响。 在大豆中已经证明的几乎没有或根本没有氮的根瘤菌的植物防御能力将在施加细菌肿胀的物种中进行测试。 这项研究将增加对为农业和自然生态系统提供氮的共生的理解，对其他重要的共生性产生影响。 结果可以指导农作物的开发，这些农作物有选择地富集了最佳根茎的土壤，从而减少了未来的肥料需求。 将为大学生，至少一名研究生和一名博士后研究员提供教育机会。 两名女学生已经赢得了在首席研究员实验室进行的国际科学博览会的旅行，在那里，这种指导将继续是当务之急。