Endosperm is the major storage tissue of cereals and is vastly important for human and livestock nutrition and, increasingly, for industrial purposes. Endosperm comprises several different cell types, each with specific biological functions that influence the biochemical composition and agronomic quality of the grain. Understanding how these cell types are specified and elaborated during development could enable the improvement of grain properties through biotechnology or traditional breeding. This project focuses on an endosperm cell type called aleurone. A maize gene was identified that controls the number of aleurone cells as well as the development of aleurone cell characteristics. This gene, called nkd, is duplicated on two different chromosomes and codes for a transcription factor (a protein that regulates other genes) called IDD9/IDDveg9. As such, the function of this gene is to regulate other genes that are important for endosperm development.
The project will use molecular and genetic approaches to explore the biological function of the nkd gene in endosperm development. The relative position of this gene in the regulatory hierarchy that controls endosperm development will be ascertained by examining the temporal and spatial expression patterns in normal maize grains compared to mutants that are known to affect specific steps in endosperm development. Genome-wide analysis of gene expression will reveal what genes are regulated by IDD9/IDDveg9. Finally, a link will be explored between the nkd gene and the plant hormone auxin. This research is expected to define key steps and molecules in the regulation of endosperm (aleurone) development.
In addition to the biological and potential agronomic implications, important training opportunities will be afforded to young scientists. One postdoctoral fellow, one graduate student, three undergraduate students and three summer interns will contribute to, and benefit from, these research activities. Emphasis will be placed on recruiting from area minority populations.