Elucidating the Genetic Architecture of ProVitamin A and Vitamin E Biosynthesis in Seed

Michigan State University, East Lansing MI

Investigators

Abstract

PI: Dean DellaPenna (Michigan State University) CoPIs: C. Robin Buell (Michigan State University), Edward S. Buckler (Cornell University/USDA-ARS), and Torbert R. Rocheford (Purdue University) Key Collaborators: Michael A. Gore (University of Arizona/USDA-ARS) and Jianbing Yan (CIMMYT, Mexico) Senior Personnel: Dick Johnson (University of Illinois at Urbana-Champaign) and Theresa M. Fulton (Cornell University) Carotenoids are a group of several hundred distinct chemical compounds that are essential for vision and immune system function and as natural colorants in fresh and processed foods. Some carotenoids (betacarotene, alpha-carotene and beta-cryptoxanthin) are the major provitamin A compounds in the human diet while others such as lutein and lycopene play a role in decreasing the incidence and severity of macular degeneration or prostate cancer, respectively. The goal of this project is to identify the genes and their most useful variants (alleles) in maize that determine the levels and compositions of carotenoids and vitamin E in maize seed. Using information obtained using the model plant Arabidopsis, maize genes corresponding to those responsible for the biosynthesis of carotenoids and vitamin E will be identified. Knowledge of the natural variation in the content and composition of these compounds in maize seed will be combined with the recently published genome sequence of maize and detailed analysis of gene expression during maize seed development to determine which specific alleles of these genes contribute the most to beneficial levels of these compounds in maize seed. The alleles identified can then be used in maize breeding programs to increase the levels of these compounds to enhance the quality of food and feed derived from maize. This same approach will also enable the identification of new and novel genes that play significant roles in determining the levels of carotenoids and vitamin E in maize. The combined information obtained will provide a road map for generating similar changes for these and other vitamins in other agricultural crops that serve as major food and feed sources for humanity. Understanding the molecular genetic basis of biochemical traits in agricultural seed crops that are essential for nutrition in humans and animals is a key component of meeting future global food and feed needs. The research will provide a comprehensive genetic assessment of natural variation in two such biochemical pathways and will serve as a model for genome scale integrative analysis of other areas of plant metabolism in maize and other agricultural plant species. The large body of publically available gene expression data generated in this study will provide an unparalleled resource that will greatly impact the maize research community. The research will provide a unique environment for educating the next generation of scientists through engagement of high school, undergraduate, and graduate students as well as postdoctoral associates in research at interfaces of plant genetics, genomics, quantitative genetics and plant biochemistry. The researchers will engage under-represented groups in plant scientific research through targeted recruitment of Hispanic undergraduates to the research programs at all three universities. This outreach will include educating preschool children, K-12 students, and undergraduates in the concepts of genetics, plant breeding, biochemistry, nutrition, food sources and their relevance to diet and health. As vitamin deficiencies are a pervasive global health issue, a practical outcome of this research will be to provide the basis for more expedient and cost effective marker-assisted selection programs in maize for enhanced dietary levels of carotenoids and vitamin E in the US and developing countries. Toward this end, the project have established a network with researchers at CIMMYT (Mexico) and IITA (Nigeria) to facilitate seamless transfer of relevant results into active international breeding programs targeting developing countries. All data generated through this project will be available at the project website (http://www.maizegenomics.plantbiology.msu.edu) and through long-term data repositories that include the NCBI GEO (http://www.ncbi.nlm.nih.gov/geo/) and Short Read Archive (http://www.ncbi.nlm.nih.gov/Traces/sra/sra.cgi), MaizeGDB (http://www.maizegdb.org/) and TAIR (http://www.arabidopsis.org/).