CSU Researchers Use Transgenic Technology
in a Variety of Ways.

Dr. Anireddy S.N. Reddy
Department of Biology

Dr. Reddy’s laboratory is developing a potato variety that is resistant to late blight, the fungal disease that caused the Irish potato famine in the 1860s. Dr. Reddy and his co-workers have found two genes in Arabidopsis thaliana that inhibit the growth of fungi. They have inserted these genes into the DNA of potato plants using Agrobacterium as the vehicle for transformation. In greenhouse trials, the transformed plants were exposed to late blight (Phytophthora infestans) and to early blight (Alternaria solani). Disease symptoms from exposure to late blight were reduced by up to 70% and disease symptoms from exposure to early blight were reduced by up to 82%. Field trials are now underway to confirm that results from tests in the laboratory and greenhouse predict disease resistance under field conditions.

Potatoes are an important food crop, following wheat, rice, and maize in worldwide production. The San Luis Valley of Colorado is one of the centers for production of “seed” potatoes, that is, potatoes that will be planted to produce the crop for market. Because both early blight and late blight occur in Colorado, a blight-resistant potato cultivar could benefit farmers in this area.

Dr. Reddy’s web page is available at http://www.colostate.edu/Depts/Biology/Faculty/reddy.htm

Dr. June Medford
Department of Biology

DrMedford’s laboratory uses transgenic Arabidopsis plants to study the influence of naturally produced plant hormones on the development of plant shoots. The isolation of hormone suppressing genes and the characterization of the regulation of gene expression should help to elucidate the biological mechanisms by which plants control their growth.

Dr. Medford maintains a web site at http://www.colostate.edu/Depts/Biology/Faculty/medford.htm.

The main project is centered upon the interaction between the model plant Arabidopsis thaliana and the necrotrophic fungus Alternaria brassicicola. Dr. Lawrence’s laboratory is using several approaches to study the molecular basis of resistance to this pathogen. Once disease resistance genes are isolated from Arabidopsis, they can be transferred to other crops such as cabbage, canola, and other crucifers that are susceptible to this pathogen.

Another project, funded by the University of Kentucky Research Foundation, is centered upon increasing resistance to tobacco blue mold, a downy mildew type of disease caused by the fungus Peronospora tabacina. This disease costs Kentucky farmers over 100 million dollars per year and threatens to interfere with “molecular farming” of tobacco for the production of vaccines and pharmaceuticals. Dr. Lawrence’s lab is employing several strategies for developing transgenic plants with increased blue mold resistance, including expressing genes that encode antifungal enzymes as well as modifying the plant’s inherent defense system. The final anticipated stage of the project is to tailor or adapt these strategies to control pathogens of economic importance in Colorado.

Dr. Lawrence maintains a web site at http://lamar.colostate.edu/~clawrenc/.

Dr. Cecil Stushnoff
Department of Horticulture and Landscape Architecture

Dr. Stushnoff’s laboratory is working on the processes by which plants stabilize their tissues when they are exposed to environmental stresses including low temperature, high temperature, and excessive salt. Petunia plants transformed via Agrobacterium to produce the sugar mannitol are used as a model plant system to explore physiological responses to salinity and low temperature stresses.

Dr. Stushnoff maintains a web page at http://www.colostate.edu/programs/pbp/.

Dr. Patricia Bedinger
Department of Biology Dr. Bedinger’s laboratory uses transgenic Arabidopsis and transgenic tomato plants to study the role of pollen proteins in pollination. Pollination is a complex process involving the exchange of molecular signals between the pollen grains and the stigma on which they fall. Transgenic plants may help to elucidate the methods that the pollen grains and the stigma use to recognize each other.

Dr. Bedinger maintains a web page at http://www.colostate.edu/Depts/Biology/Faculty/bedinger.htm.

Dr. Pilon-Smits and her research team are using genetic engineering to improve the natural phytoremediation properties of plants. Phytoremediation, or using plants to remedy undesirable conditions, is emerging as an important approach to environmental pollution. While many plants are killed or severely stunted by the presence of selenium and heavy metals in the soil and water, some plants are able to tolerate these chemicals and can even change the chemicals into less toxic forms. These traits may be valuable in the effort to clean up pollutants such as the chemicals left in the soil around an abandoned mine. Dr. Pilon-Smits uses Indian mustard (Brassica juncea) as a model system. This plant is a good remediator of most trace elements, and it can be genetically engineered. Eight enzymes involved in selenium or heavy metal accumulation have already been produced in larger-than-normal quantities in Indian mustard. Increased production of two enzymes responsible for the uptake and reduction of selenate resulted in increased selenium accumulation and tolerance. Other transgenic plants, overproducing the heavy metal binding peptides called phytochelatins, showed increased cadmium accumulation and tolerance. Dr. Pilon-Smits is testing some of her plants at Leadville, Colorado, where water around an old mine is polluted with heavy metals.

Dr. Pilon-Smits maintains a web site at http://lamar.ColoState.EDU/~epsmits/.