RESEARCH-PGR: Leveraging the Medicago HapMap to characterize genome-by-genome interactions in nitrogen-fixing symbiosis

研究-PGR：利用苜蓿 HapMap 来表征固氮共生中基因组之间的相互作用

基本信息

批准号：
1724993
负责人：
Peter Tiffin
金额：
$ 55.05万
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：
2017
资助国家：
美国
起止时间：
2017-08-15 至 2019-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1724993&HistoricalAwards=false
关键词：
RESEARCH PGR Leveraging Medicago HapMap

项目摘要

Nitrogen is required for the synthesis of amino acids and proteins, essential components of the human diet. Nitrogen is also one of the most important nutrients required by plants, and it is normally applied as fertilizer in agricultural systems. However, legumes have the ability to establish a symbiotic association with specialized nitrogen-fixing soil bacteria through the formation of root nodules where the bacteria fix atmospheric nitrogen; the fixed nitrogen is used by the plant for protein synthesis. The symbionts have mechanisms that recognize molecular signals from each other, which in turn initiate processes that lead to the formation of root nodules. However, there is significant genetic variation among bacterial strains and among legumes in their abilities to interact symbiotically. The objective of this proposal is to identify bacterial and plant genes and gene variants responsible for the most efficient and effective interactions. This objective will be accomplished by identifying the bacterial strains that outcompete other strains in a large mixture in their ability to form nodules in roots of Medicago truncatula, the barrel medic. These experiments will be carried out with a large collection of barrel medic accessions representing most of the variation in the species. Thus, the results are expected to identify the most competitive strains and plant accessions. Quantitative analysis of the DNA sequences of the most competitive types is expected to reveal the identity of the bacterial and plant genes that are the most effective in the symbiotic interaction. The project will train several undergraduate students. Biological N-fixation mediated by legume-rhizobium symbiosis contributes N to both natural and agro-ecosystems, and results in legumes having N-rich leaves and seeds that make them some of the most important sources of dietary protein. For this reason, this symbiosis is a critical component of sustainable agricultural systems. The legume-rhizobia symbiosis represents an ideal system to study the coordination of function between a bacterial and a plant genome. Although both partners benefit from this relationship, not all partnerships are equally beneficial. The outcome of host-rhizobia interactions depends on the genotypes of the partners. This means that there is not a single rhizobium strain that confers the greatest benefit to all plant genotypes, and that different rhizobia strains are favored by different plant genotypes. The objective of this proposal is to identify the genomic basis that underlies G x G variation in mutualism, which could enable manipulation of the interaction to maximize biological N-fixation. The PIs have developed a select and resequence assay to identify strains with the greatest fitness in a diverse multistrain community. The PIs are proposing to refine and evaluate the robustness of the performance of this assay that will satisfy various biological and statistical challenges. The Broader Impacts of this project include the direct benefits to the agricultural sector and the environment that will result from more efficient nitrogen-fixation systems and the training of undergraduate students.

合成氨基酸和蛋白质的氮是人类饮食的重要组成部分所必需的。氮也是植物所需的最重要的营养物质之一，通常在农业系统中作为肥料施用。但是，豆类具有通过形成细菌固定大气氮的根结节的形成，可以与专门的氮固定土壤细菌建立共生缔合。植物使用固定的氮用于蛋白质合成。共生体具有识别彼此分子信号的机制，这反过来启动了导致根结节形成的过程。然而，细菌菌株和豆类之间的遗传变异存在显着的遗传差异。该提案的目的是确定负责最有效相互作用的细菌和植物基因和基因变体。该目标将通过鉴定细菌菌株在大型混合物中胜过其他菌株的细菌菌株，它们能够在桶形医疗的Medicago truncatula根部形成结节。这些实验将使用大量代表该物种的大部分变化的桶形药物垫进行。因此，结果预计将确定竞争性最高的菌株和植物加入。对最有竞争力类型的DNA序列的定量分析有望揭示在共生相互作用中最有效的细菌和植物基因的身份。该项目将培训几名本科生。豆类rhizobium sembiosis介导的生物N固定构成氮有助于天然和农业生态系统，并导致豆类具有富含N的叶子和种子，使它们成为饮食中最重要的来源。因此，这种共生是可持续农业系统的关键组成部分。豆科植物共生的豆科症代表了研究细菌和植物基因组之间功能协调的理想系统。尽管双方都从这种关系中受益，但并非所有伙伴关系都同样有益。宿主 - 毛病相互作用的结果取决于伴侣的基因型。这意味着没有单一的根茎菌株赋予所有植物基因型最大的好处，并且不同的根瘤菌菌株受到不同植物基因型的青睐。该建议的目的是确定基因组基础，该基因组基础是互惠性的G x g变异，这可以使这种相互作用能够操纵以最大化生物N固定。 PIS开发了一种精选和重新设备分析，以识别多元化多种环境社区中最大健身的菌株。 PI提议优化和评估该测定法的鲁棒性，以满足各种生物学和统计挑战。该项目的更广泛的影响包括对农业部门和环境的直接好处，这将源于更有效的氮固定系统以及对本科生的培训。