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 Bradlee Nelms is "Specification and Differentiation of Maize Archesporial Cells During Early Anther Development." The host institution for the fellowship is Stanford University and the sponsoring scientist is Dr. Virginia Walbot.
The fellowship activities are focused on understanding early anther development in maize. As a reproductive organ of a major crop plant, the maize anther plays a central role in many processes of agronomic importance. Defects in early anther development lead to male sterility, decreasing grain number and yield in many cereal crops. Furthermore, one of the earliest causes of yield loss in response to heat and drought is pollen inviability; thus, understanding anther development and male fertility will be important to insuring food security in the face of climate change. This project will increase knowledge of basic reproductive biology, information that can ultimately lead to breakthroughs in crop breeding and yield enhancement. The fellowship activities will also promote teaching and learning both within academia and in the general public. The fellow will lead an undergraduate-focused outreach project to design and market educational materials, helping to communicate the broad importance of the plant sciences to the community and stimulating collaboration between undergraduates from scientific fields and other disciplines. Further educational outreach will include mentoring undergraduate and high school students in laboratory research.
The overarching scientific goal of this research is to uncover early events in the development of archesporial (AR) cells--the first cell type within the anther committed to meiosis and pollen production. Major aims are to (1) identify cellular intermediates as AR cells differentiate into meiocytes and (2) investigate the role of TGA-type transcription factors in AR cell specification. These aims will be pursued using a combination of genomics, genetics, and biochemistry. Single-cell RNA sequencing will allow the identification of distinct AR cell populations, which will then be ordered into a developmental pathway by integrating transcriptome data with in situ localization of RNA transcripts. The subcellular localization, redox status, and DNA binding activity of several TGA transcription factors will be assessed in early stage anthers under various genetic and physiological perturbations, and downstream signaling pathways for the TGA factors will be evaluated by chromatin immunoprecipitation. Together, the fellowship activities will generate substantial transcriptomic and ChIP-Seq data, clarify the differentiation program of AR cell development, and help to characterize the regulation and signaling of TGA family transcription factors during AR cell specification in a spatio-temporal context. Research results will be presented at national conferences and published in peer-reviewed journals, and all sequence data will be submitted to public repositories such as the NCBI Sequence Read Archive (www.ncbi.nlm.nih.gov/sra) and Gene Expression Omnibus (www.ncbi.nlm.nih.gov/geo/).
