Georgia Davis  Co-PI  DavisGE@missouri.edu  (573) 882-9224

Assistant Professor 53 Agriculture Building Department of Agronomy University of Missouri -- Columbia Columbia, MO 65211-7020

PhD 1989, University of Wisconsin 

Maize Genomics
Research interests in my laboratory include both structural and functional genomics. Specific research areas are: 1)Molecular mapping including recombinational analysis, physical mapping, and the relationship of gene order across grass species; 2)Fungal resistance in maize with emphasis on mechanisms and sources of resistance to Aspergillus flavus and aflatoxin production; 3)Insect resistance in maize, specifically fall armyworm and southwestern corn borer and their relationship to juvenility associated traits.

Structural GenomicsAs part of the National Science Foundation funded Missouri Maize Project, we are constructing a high-resolution maize genetic map using RFLP and SSR markers. An overall goal of the Missouri Maize Project is to produce a physical map in maize. My laboratory is responsible for mapping markers from the genetic map onto the physical map. The common markers will provide reference points to orient the genetic and physical map relative to one another. In addition, the genetic map will serve as a bridge between prior molecular maps and the maize physical map. All map data and associated information is available through the Maize Genome Database.

Fungal Resistance--Aspergillus flavus is a ubiquitous soil-born fungus. It infects many important crop plants including corn, rice, sorghum, cotton, fruit and nut trees, and peanuts. Some strains of A. flavus are capable of producing aflatoxin if they infect a host plant at the correct developmental stage. Aflatoxin is a human health concern because it has been associated with liver cancer in mammals. We are working to identify the genes present in tropical corn that result in reduced toxin accumulation in corn kernels. So far we have identified 8 chromosome regions containing genes which lower aflatoxin levels in corn. Current research is directed at identifying the genes and the mechanism by which they reduce aflatoxin accumulation.

Insect Resistance--Fall armyworm and Southwestern corn borer are both Lepidopteran insects which can cause significant damage to corn plants beginning at the whorl stage of development. Fall armyworm has a very broad host range including more than 60 plant species. Southwestern corn borer has a narrow host range, mainly corn and sorghum. We are working to identify the genes in tropically-derived corn lines that result in less insect feeding. So far we have identified 3 chromosome regions containing fall armyworm resistance genes. One of these regions contains a gene that controls the presence of adult leaf wax and the number of juvenile leaves on a corn plant. More juvenile leaves means plants are more susceptible to insect damage. Current research is directed at identifying the genes for insect resistance and they mechanism(s) by which they reduce insect damage.

Selected publications:

Davis, G.L., M.D. McMullen, C. Baysdorfer, T. Musket, D. Grant, M. Staebell, G. Xu, M. Polacco, L. Koster, K. Houchins, S. Chao, and E.H. Coe, Jr. 1999. A Maize Map Standard with Sequenced Core Markers, Grass Genome Reference Points, and 932-ESTs in a 1736-Locus Map. Genetics 152:1137-1172.

Byrne, P.F., M.F. Berlyn, E.H. Coe Jr., G.L. Davis, M.L. Polacco. D.C. Hancock, and S.I. Letovsky. 1995. Reporting and accessing QTL information in USDA's maize genome database. Journal of Quantitative Trait Loci (electronic journal available on the WWW at http://probe.nalusda.gov:8000/otherdocs/jqtl/).

Coe, E.H., M. Polacco, G. Yerk, and P.F. Byrne. 1994. Genetic data and genetic mapping Some current perspectives. Maydica 349: 47-51.