Research Topics
Department of Crop Science, USDA/ARS, and Maize Genetics Cooperation •
Stock Center
Ph.D. (1981) University of California (Berkeley)
Research Topics
Research Interests
The research in my laboratory involves the analysis of the anaerobic-stress response in Zea mays. During anaerobiosis there is an immediate repression of preexisting protein synthesis followed by an induction of gene expression involving the selective synthesis of approximately twenty anaerobic-specific proteins. Among these anaerobic proteins (ANPs) are the alcohol dehydrogenase (ADH) isozymes encoded by the adh1 and adh2 genes as well as other genes encoding enzymes involved in glycolysis and glucose phosphate metabolism.
The anaerobic-stress response of maize offers a unique opportunity to characterize the regulatory components of a family of twenty genes that are coordinately expressed. The anaerobic-specific proteins appear to be encoded by a set of genes whose expression is stimulated by a deprivation of oxygen, a condition that would occur in nature during flooding. Regulation of protein synthesis under anaerobiosis appears to occur at both the levels of transcription and translation. Among these anaerobic proteins (ANPs) are enzymes involved in glycolysis and related processes. However, we also found two inducible genes that have different functions. One that has homology to xyloglucan endotransglycosylase may be involved in aerenchyma (cortical air space) formation during flooding (allowing transport of oxygen from the leaves to the submerged, oxygen deprived, roots of a plant).
Our molecular research approaches include analysis of the enhancement of transcriptional and translational expression of this set of genes during anaerobic-stress and analysis of the signal transduction pathway leading to the anaerobic-response.
We are also analyzing genes that confer increased flooding (anaerobic) tolerance in maize. This trait was found in some exotic maize accessions. Genetic analysis indicates that tolerance is a fairly simple dominant trait. Additionally, we found a recessive factor that increases flooding tolerance in plants that are null for ADH activity. Our goals are to isolate and characterize the genes involved in flooding tolerance and to determine the feasibility of using this trait in developing flooding tolerant inbred lines for breeding purposes.
The Maize Genetics Cooperation Stock Center has been a major part of the UI Department of Agronomy (now Crop Sciences) since 1953. Over the past 15 years, USDA/ARS began playing an increasingly active role in supporting the operations of the stock center. While the Maize Genetics Cooperation • Stock Center continues to be housed in the UI Department of Crop Sciences, in 1992, ARS took over the day to day operations of the stock center and an ARS scientist was appointed as Director.
It is the goal of the Maize Genetics Cooperation Stock Center to have available, stocks containing all known allelic and cytological variation in maize and information about them. Information about maize mutants and chromosomal aberrations as well as their use in biological research has been published over the years. This information is presently being incorporated into the Maize Genome Database (http://www.maizegdb.org/). Any available stock(s) will be sent upon request without charge. The materials at the stock center are also available to educational institutions for teaching purposes. My area of research is presently expanding to include the molecular genetic analysis of several maize mutant alleles that are in stocks at the Maize Genetics Cooperation • Stock Center.
Key Words Recombinant DNA, Introduction of DNA into Plant Cells, Gene Expression Systems, DNA-Protein Interactions, Molecular Evolution, Genome Organization/RFLP Mapping, Monoclonal Antibodies, Bioengineering, Site-Directed Mutagenesis, Protein Purification and Characterization, Environmental Biotechnology, Plant Cell and/or Tissue Culture, Plant Transformation, Signal Transduction Pathway Analysis, Mutant Analysis
Current Research Funding
USDA/ARS