Soybean is a major crop with the ability to fix atmospheric nitrogen through symbiosis with soil bacteria. Legumes like soybean annually fix 60 million metric tons of nitrogen, which have a fertilizer replacement value of $7- 10 billion. A long-term goal of N2 fixation research is to transfer the symbiotic ability of legumes to non-legume crops like corn or tomato. However, there are gaps in our understanding of the complex events that occur after the bacteria penetrate the root. These gaps are hindering efforts to engineer nitrogen fixation into non-legumes. Hence, the main objective of this project is to elucidate the initial events that take place during the formation of structures that mediate the movement of bacteria through the root. This project will use high-resolution methods to characterize macromolecular events at a single-cell level. The experimental data will be analyzed with sophisticated modeling tools to improve our understanding of the first events of the legume-bacterial interactions that lead to symbiosis. The knowledge gained will support efforts to transfer the rhizobial symbiosis to non-leguminous plants. In addition to the research mission, the project will create new programs to provide transformative elementary education, as well as training programs for the professional development of middle school and high school teachers. Finally, this project will develop an innovative Sophomore Bioinformatics/Plant Science program to provide integrated training in plant research and bioinformatics.
Data integration and system modeling of complex biological processes require detailed, functional genomic data, preferably obtained in a cell-specific way in order to avoid the effects of signal dilution due to the presence of non-responding cells. The long-term goal of this project is to further basic understanding of the agronomically important soybean N2 fixing symbiosis. A unique focus of this project is the ability to sample and analyze the transcriptome, proteome and metabolome at a single-cell resolution. These methods, as well as sophisticated data analysis and modeling tools, will be applied to the intermediate stages of soybean nodulation; specifically, the infection thread progression and bacterial release into nodule cells. These are key events in nodule formation/function that remain largely undefined. The data generated will be used to construct predictive, computational models of the plant response to rhizobial infection thread initiation and growth. The knowledge gained from this research, together with precision breeding techniques, will be instrumental to improving soybean quality and meeting the growing demand for food and fuel expected in the forthcoming years. Moreover, filling in the gaps in our understanding of the rhizobial-legume infection process will be critical to ongoing efforts to transfer this symbiosis to non-leguminous plants (e.g., maize). The project also includes strong outreach programs focusing on the introduction of plant science to elementary, high school and undergraduate students.
