NSF Postdoctoral Fellowship in Biology FY 2016

Ellis Nathanael, St. Louis MO

Investigators

Abstract

This action funds an NSF National Plant Genome Initiative Postdoctoral Research Fellowship in Biology for FY 2016. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Nathanael Ellis is "Identifying molecular networks underlying root-root interactions in high plant density adapted maize." The host institutions for the fellowship are the Donald Danforth Plant Science Center and the Washington University School of Medicine, and the lead sponsoring scientist is Dr. Christopher Topp, with co-sponsoring scientist Dr. Yuan-Chuan Tai. Since the 1930's, annual gains in U.S. maize production have largely been driven by the adaptation of maize plants to increasing plant density. Two historically important maize populations, Iowa Stiff Stalk Synthetic and Corn Borer, have been recurrently selected for increased hybrid grain yield, resulting in density adapted plants. Preliminary work suggests that not only have root architectures changed in these populations, but their sensing and growth responses to neighboring root systems have changed as well, pointing to a new paradigm for understanding the key process of crop density adaptation. This project aims to identify the molecular mechanisms of adaptation to high plant density in maize roots. Thus the research will contribute to our basic understanding of how roots, the "hidden-half" of plants, communicate with one another, and exploit this knowledge for crop improvement. The broader impacts include synergistic training between plant biologists and medical imaging experts, as well as leveraging the project research objectives to develop teaching tools in a classroom experience for underserved students. Training will include: bioinformatics, genomics, advanced image analysis methods, analysis of complex 3D structures, and statistical approaches to quantify the dynamics of plant metabolism. Shoot architectures, specifically increased leaf angles, are known outcomes of selection during maize density adaptation, but little empirical data exists about the contribution from roots. Selected cycles from progressively density adapted germplasm will be assayed in several ways to quantify root system architecture of plants grown individually or paired, to identify changes in root growth as a function of density adaption. In this project, the effects of density adaptation on 3D root architecture and growth will be assayed by Optical Projection Tomography (OPT), and Positron Emission Tomography (PET) to study dynamic carbon allocation. These efforts will identify the most relevant time points from which to sample leaf and root tissue for transcriptional profiling, as well as profiling of root exudates via gas chromatography-mass spectrometry. This project will contribute to modelling the relationship of carbon allocation and root growth in respect to root-root communication and to identify the underlying genetic mechanisms controlling these processes. Results from this project will be published in peer-reviewed journals, as well as communicated at scientific conferences. Data will be uploaded to appropriate publicly accessible websites, including the NCBI Sequence Read Archive in association with the maizegdb.org/expression database, as well as the Proteomics Identifications database.