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

University Of California-Davis, Davis CA

Investigators

Abstract

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.