Genetic Engineering of Oat: Dr. Geeta Menon, a postdoctoral
research associate, has been conducting research on the optimization of
novel selection systems for transgenic oat and the transformation of oat
with genes encoding antifungal proteins. An efficient system for selection
of transgenic oat cultures using only visual selection for expression of
the green fluorescent protein (GFP) gene has been developed and is being
routinely utilized to generate fertile, transgenic plants. Transgene integration
was confirmed using Southern blot and PCR procedures. GFP expression was
determined visually. Progeny of transgenic plants analyzed to date display
high level expression of the GFP gene segregating in a normal, 3:1 (expressing:nonexpressing),
Mendelian ratio for a dominant, heterozygous gene. In collaborative research
with Dr. Dave Somers, University of Minnesota, fertile transgenic plants
of elite oat varieties such as Belle and Dane were generated using model
marker genes. Efforts are now underway to transform elite varieties with
agronomically useful transgenes. Fertile, transgenic plants containing
a transgene encoding a thaumatin-like, PR-5, protein have been generated
and are undergoing expression and inheritance analysis. Transgenic lines
expressing the antifungal gene will be tested for enhanced resistance to
crown rust in seedling and adult plant assays in collaboration with Dr.
Kurt Leonard, USDA-ARS Cereal Disease Research Unit, St. Paul, MN. Plantlets
containing a second, unrelated antifungal transgene are being regenerated
at this time and will soon be moved to rooting medium.
Mapping Crown Rust Resistance Genes Using Molecular Markers: Mr. Shuquan Zhu, working on his Ph.D. in Plant Breeding and Plant Genetics, is conducting research with the goal of mapping crown rust resistance genes in oat using molecular markers (RFLP's, AFLP's). A population segregating for crown rust resistance, introgressed from diploid wild oat (Avena strigosa) into a cultivated, hexaploid oat background, was created by crossing crown rust susceptible oat variety 'Ogle' with the crown rust resistant line MAM17-5. Results from genetic inheritance studies conducted on this population by former Ph.D. student Miglena Dilkova (under the direction of Dr. R.A. Forsberg) indicated that major genes for resistance to crown rust were segregating in this population. The population was reconstructed and notes taken on rust reactions of field grown F2 plants in a heavy rust year (1996). Field grown F3 lines were also observed under heavy rust pressure in 1997, to confirm F2 classification. Lines were advanced via single seed decent to the F6 generation in the Fall 1997 and Winter 1998 greenhouse growouts. F6 headrows will be grown in the field in 1998 for observation, scoring, and seed increase for use in replicated trials in 1999-2000. Seed is also being increased in Aberdeen, ID by collaborator Dr. Darrell Wesenberg, under lower disease and rust pressure. F7 lines will be tested and scored for rust resistance using seedling assays by collaborator Dr. Kurt Leonard, at the USDA-ARS Cereal Disease Laboratory, St. Paul, MN. Screening blots are being conducted to identify RFLP probes which are polymorphic between the parent lines. Genomic DNA will be isolated from greenhouse-grown plants of the lines in the population during the summer and fall of 1998.