BREAD: Overcoming the Domestication Bottleneck for Symbiotic Nitrogen Fixation in Legumes

PI: Douglas R. Cook（加州大学戴维斯分校）CoPI: Rajeev K. Varshney（国际半干旱热带作物研究所[ICRISAT]， Patancheru，印度）合作者：Eric von Wettberg（佛罗里达国际大学）高级人员：R. Varma Penmetsa（加州大学戴维斯分校）豆科植物是开花植物的第三大家族，在农业重要性上仅次于草类。在全球范围内，豆类贡献了人类蛋白质摄入量的三分之一，这一事实与它们通过与固氮细菌的共生关系获取大气氮的非凡能力直接相关。提供减少（“固定”）氮是所有现代农业的一个关键挑战。在发达国家，集约化农业依赖于工业生产的氮肥的投入，这些氮肥来自化石燃料的能量。然而，在世界上资源贫乏的地区，氮肥的成本使其无法使用，作物产量和土壤肥力相应地受到影响。尽管具有重要意义，但人们对豆科植物高效共生固氮的机制知之甚少，也不知道驯化和育种如何以及在多大程度上影响了祖先的共生固氮能力。该项目将描述农业环境中高效共生固氮的遗传机制，并为新一轮知识驱动的豆类作物改良战略提供知识和资源，这将使发展中国家和发达国家的农业都受益。在农业系统中，豆科植物轮作是保持土壤肥力和作物生产力的重要手段。提高豆科作物的共生固氮效率——克服驯化的遗传瓶颈——对改善资源贫乏农民的生计具有巨大潜力。该项目的目标是同时满足推动基础科学的好奇心，同时提供可以导致应用农业新工具的理解。该项目将提高国际农业研究的质量和知名度，并为青年科学家提供本科生、研究生和博士后的培训。有关该项目的信息将通过项目网站（http://www.icrisat.org/gt-bt/ICGGC/homepage.htm）提供。所有项目数据将在www.comparative-legumes.org和豆类信息系统（LIS; http://www.lis.org）上长期提供。所有序列数据也将在相关的国家生物技术信息中心（NCBI）数据库中提供。种子和细菌菌株将根据要求分别通过ICRISAT和加州大学戴维斯分校提供。

PI: Douglas R. Cook (University of California - Davis)CoPI: Rajeev K. Varshney (International Crops Research Institute for the Semi-Arid Tropics [ICRISAT], Patancheru, India)Collaborator: Eric von Wettberg (Florida International University) Senior Personnel: R. Varma Penmetsa (University of California - Davis)Legumes are the third largest family of flowering plants, and second only to the grasses in agricultural importance. On a global scale, legumes contribute 1/3 of humankind's protein intake, a fact that is directly related to their unusual capacity to access atmospheric nitrogen through symbiosis with nitrogen-fixing bacteria. Provision of reduced ("fixed") nitrogen represents a key challenge in all modern agriculture. In the developed world, intensive agriculture depends on the input of industrially-produced nitrogen fertilizers, derived from the energy of fossil fuels. In resource poor areas of the world, however, the cost of nitrogen fertilizers is prohibitive to their use, and crop yields and soil fertility suffer proportionally. Despite the important implications, little is known about the mechanisms that underlie efficient symbiotic nitrogen fixation in legumes, or how and to what extent domestication and breeding has impacted the ancestral capacity for symbiotic nitrogen fixation. This project will characterize the genetic mechanisms that underlie efficient symbiotic nitrogen fixation in the agricultural context, and contribute knowledge and resources to a new round of knowledge-driven legume crop improvement strategies that will benefit developing-world and developed-world agriculture alike.In agricultural systems crop rotation with legume species is an important means to maintain soil fertility and crop productivity. Increasing the efficiency of symbiotic nitrogen fixation in legume crops - overcoming the genetic bottleneck of domestication - has great potential to improve the livelihoods of resource poor farmers. The goal of this project is to simultaneously satisfy the curiosity that drives basic science, while providing understanding that can lead to new tools for applied agriculture. This project will enhance quality and visibility of international agricultural research, and provide for the training of young scientists as undergraduate, graduate and postdoctoral students. Information about the project will be available through a project website (http://www.icrisat.org/gt-bt/ICGGC/homepage.htm). All project data will be available at www.comparative-legumes.org and the Legume Information System (LIS; http://www.lis.org) long-term. All sequence data will also be available at the relevant National Center for Biotechnology Information (NCBI) databases. Seed and bacterial strains will be available through ICRISAT and the University of California - Davis, respectively, upon request.