Stephen Moose

Ph.D.: Genetics & Crop Science (co-major), North Carolina State University — 1995

B.S.: Biology, Case Western Reserve University — 1990

Comparative Genomics of Cereal Gene Promoters

Once changes in mRNA expression are identified between genotypes or environmental treatments, the question of how these changes are mediated becomes important. Our laboratory is developing an integrated functional approach to address this question. We begin by cloning and sequencing maize promoters. The maize promoter sequences are then compared to promoters from orthologous genes in rice and other cereals by computational methods to identify putative cis-acting promoter regulatory sequences conserved during cereal evolution. The functional significance of these putative regulatory sequence elements are then tested by determining whether these sequences interact with DNA binding proteins and by the introduction of promoter-reporter genes into transgenic maize or rice. We are initially applying these methods to the study of promoters from genes that are expressed in seeds. A more detailed understanding of promoter structure and promoter activities during seed development will lead to the more efficient modification of cereal grain through biotechnology for feed and processing traits.

Maize Leaf Epidermal Cell Differentiation

Maize seedling leaves differ from the adult leaves that are produced later in development for a variety of leaf epidermal traits, including wax deposition, the formation of specialized cell types such as leaf hairs, and the biochemical composition of the cell wall. The maize Glossy15 gene encodes a DNA-binding protein that coordinately regulates this diverse set of leaf epidermal traits. I am using functional genomics approaches to dissect the regulatory networks through which Glossy15 acts to control leaf epidermal cell differentiation. My laboratory has generated transgenic maize plants that overexpress the Glossy15 gene. We are performing mRNA expression profiling between normal and glossy15 mutant plants to determine those genes whose expression is regulated by Glossy15. We have also used genetic screens to identify mutations that represent candidate targets of Glossy15 regulation in wax synthesis, hair formation, and cell wall composition.

Molecular Genetic Characterization of the Illinois Protein Strains

The University of Illinois has been conducting since 1896 long term selection experiments for changes in the relative concentrations grain protein. These selection experiments are now in their 100th generation and have resulted in the creation of four strains, all derived from the same source population, that span the extremes for grain protein composition:

• Illinois High Protein (IHP, ~35% grain protein)
• Illinois Low Protein (ILP, ~4% grain protein)
• Illinois Reverse High Protein (IRHP, ~5% grain protein)
• Illinois Reverse Low Protein (IRLP, ~18% grain protein)

The Reverse strains were created by reversing the direction of selection after generation 48, e.g. Illinois Reverse Low Protein was created by selecting Illinois Low Protein for high grain protein.

These Illinois Protein Strains represent a unique genetic resource to investigate questions related to the physiological and molecular mechanisms that influence the ability of corn plants to assimilate, translocate, partition, and store carbon and nitrogen, especially within the seed.
In collaboration with Dr. Fred Below's laboratory in the Department of Crop Sciences, we have initiated a project to characterize differences in gene expression among the Illinois Protein Strains and correlate these to changes in grain composition and physiological responses to different rates of supplemental nitrogen under replicated field plot conditions. Our initial research focus is on genes known to participate in seed storage protein deposition and nitrogen metabolism in both seed and vegetative tissues. This research promises to reveal novel approaches for improving nitrogen use efficiency and modifying grain composition in commercial maize hybrids.

Uribelarrea, M., Moose, S.P., and Below, F.E. (2007)  Divergent selection for grain protein affects nitrogen use efficiency in maize hybrids.  Field Crops Res. 100: 82-90

Lauter, N., Kampani, A., Carlson, S., Goebel, M. and Moose, S.P. (2005) microRNA172 downregulates glossy15 to promote vegetative phase change in maize. Proc. Natl. Acad. Sci 102: 9412-9417.

Seebauer, J., Moose, S.P., Fabbri, B., Crossland, L. and Below, F.E. (2004)  Amino acid metabolism in young maize earshoots: implications for assimilate movement and nitrogen signaling.  Plant Physiol. 136: 4326-4334

Hwang, Y.S., Ciceri, P., Parsons, R., Moose, S.P., Schmidt, R.J. and Huang, N. (2004)  The maize O2 and PBF proteins act additively to promote transcription of storage protein gene promoters in rice endosperm cells.  Plant and Cell Physiology 45: 1509-1518.

Moose, S.P., Rocheford, T.R. and Dudley, J.W. (2004).  Maize selection turns 100: a 21st century genomics tool.  Trends in Plant Science 9: 358-364.  doi:10.1016/j.tplants.2004.05.005

Uribelarrea, M., Below, F.E. and Moose, S.P.  (2004).  Grain composition and productivity of maize hybrids derived from the Illinois Protein Strains in response to variable nitrogen supply. Crop Science 44: 1593-1600.