Elucidating the symbiotic signaling pathway in legumes

University Of California-Davis, Davis CA

Investigators

Abstract

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. Biological nitrogen fixation also makes legumes key components of both natural and agricultural systems because they return vital nitrogen to the environment. This project will extend existing knowledge of how legumes and their symbiotic bacteria establish this unique partnership, in particular by bridging traditional genetic methodologies with specialized tools that the investigators have developed for protein biochemistry and cell biology. The outcome of these studies will be increased understanding of a critical phase in symbiotic development, namely the period during which legumes select efficient symbiotic bacteria from the soil environment. In particular, the proposed research will identify new genes and proteins that underlie symbiotic nitrogen fixation. Knowledge of symbiotic nitrogen fixation has great relevance to agricultural systems, because US agricultural is highly dependent on input nitrogen, which for non-legumes involves consumption of fossil fuels to drive conversion at atmospheric nitrogen (N2) to fertilizer nitrogen. The fact that legumes produce fertilizer nitrogen directly, using solar energy obtained through photosynthesis, makes them key components of cost-effective, carbon-neutral, sustainable agricultural systems. Increased understanding of symbiotic development will enhance our ability to constructively manipulate this vital biological process. The anticipated broader impacts of this work include training of graduate students, and students will participate in an active international collaboration with scientists in the Republic of Korea through the Korean Rural Development Administration.