Estimating the frequency and impact of transgene introgression from wheat to jointed goatgrass:
Funded by USDA grant 2007-33120-16481
Principle Investigators:
John McKay (Evolutionary Genetics)
Patrick Byrne (Molecular-Quantitative Genetics)
Nora Lapitan (Plant Molecular Genetics and Cytogenetics)
Phillip Westra (Weed Control Systems and Herbicide Metabolisms)
Aegilops cylindrica (jointed goatgrass) competes directly with wheat production decreasing yields and profitability to wheat farmers in the U.S. An increased interest in developing more effective weed control has resulted. Currently, an effective strategy is using an herbicide resistant transgenic variety of wheat, and controlling the jointed goatgrass with herbicide. The concern of this project is in the development of transgenic wheat and the movement of transgenes from wheat to Ae. cylindrica. Ae. cylindrica and wheat share a common ancestor, Ae. tauschii, and therefore both contain a common D genome. Hybridization between Triticum aestivum L (hard red winter wheat) and Ae. cylindrica has been documented and in Eastern Colorado a mean hybridization rate of 0.1% and a maximum hybridization rate of 1.6% has been determined (Gaines et al. 2008). Subsequent backcrosses of the F1 hybrid to Ae. cylindrica would provide a mechanism of gene introgression from wheat to Ae. cylindrica. Development of transgenic wheat, including herbicide resistance and drought tolerance, could transfer the advantageous transgenes into Ae. cylindrica making the weed more competitive and more difficult to manage.
Objectives:
1. a. Estimate the rate of backcross between F1 hybrids (Triticum aestivum x Aegilops clindrica) with Ae. cylindrica as the pollen donor.
b. Determine the fertility and chromosome composition of the BC1 and further backcross generations.
2. Determine sequences specific to each Aegilops diploid genome to use to track the transfer of wheat DNA to the Ae. cylindrica genome.
3. Use 30 Western U.S. populations to compare phenotypic traits in Ae. cylindrica, especially drought tolerance.
4. a. Sample the genetic diversity of jointed Ae. cylindrica in U.S. and Eurasian populations to study the introduction history and lineage of Ae. cylindrica.
b. Compare determined phenotypic diversity to genetic diversity.
