The proposed research will determine functions for genes expressed in the Arabidopsis female gametophyte (FG, embryo sac) with the long-term goal of identifying the gene regulatory networks controlling FG cell specification and differentiation. The FG is an integral part of the plant life cycle and plays critical roles in essentially every step of the angiosperm reproductive process including pollen tube guidance, fertilization, activation of seed development, and maternal control of seed development. Using mRNA-based assays, the proposed research will identify a battery of genes including members of transcription factor gene families expressed in each of the FG cells of Arabidopsis. FG cell-specific patterns of gene expression will be further characterized using promoter:reporter lines. To determine whether any of these genes have functions in FG cell specification or differentiation, corresponding T-DNA mutant lines will be analyzed for defects in FG development and function. To establish the positions of FG transcription-factor genes relative to one another in the gene regulatory circuitry of the FG, altered patterns of promoter:reporter expression will be assayed in the presence of various FG mutations. Finally, to elucidate the gene-regulatory networks operating in these cells, a combination of biochemical, genetic, and molecular biology approaches will be used to establish direct connections between selected transcription-factor genes expressed in specific cells of the FG and their targets. Data from these experiments including the identity of confirmed genes expressed in the FG and all corresponding patterns of expression will be shared with the community at fgproject.biosci.arizona.edu or www.femalegametophyte.org . Research activities will be coordinated through interaction with research groups in the US and abroad with interests in FG development and other aspects of the project. The significance of the proposed work in relation to the overall 2010 Project objectives in determining gene functions is twofold. First, the proposed studies will identify gene expression patterns and any corresponding functions required for plant reproduction. Second, identification of gene-regulatory networks of the FG will contribute to the goal of understanding how gene circuitries control plant processes. Ultimately, results from these studies will be critical for designing strategies to modify reproductive processes in plants for improved seed yield and quality.
The broader educational impacts of this project will enhance the infrastructure of research and training at the Universities of Utah and Arizona through the continued instruction of undergraduate and graduate students, and training of postdoctoral researchers. An important goal of the project is to increase the representation of underrepresented minorities in science and to communicate science through outreach to K-12 teachers and to nonscientists. Graduate and undergraduate researchers will be recruited from the local community colleges and/or underrepresented student populations at the Universities of Utah and Arizona.
Project Websites: http://fgproject.biosci.arizona.edu/ or http//www.femalegametophyte.org
