Davis researchers are working on a groundbreaking plant genome project funded by a three-year $6.8 million grant from the National Science Foundation.

The project could speed up the development of wheat varieties with improved grain quality and nutrition, higher yield, resistance to pests and diseases, and tolerance of adverse climate conditions.

Led by geneticist Jan Dvorak from the UC Davis Department of Plant Sciences, the project received the largest award from the NSF Plant Genome Program this year. It seeks to construct a physical map of one of the three genomes making up the chromosome complement of wheat — a task far tougher than mapping the human genome.

"Unlike the mammalian genomes, genomes in higher plants differ enormously in size," Dvorak says "Each of the three wheat genomes, for example, is an order of magnitude larger than the genome of rice.

We have never had the technology to physically map and sequence huge genomes such as those of wheat."

A physical map is a representation of the order of genes and other landmarks along a chromosome. To construct a physical map, genomic DNA is fragmented, and fragments are cloned and "fingerprinted."

Overlaps between fingerprints are used to identify neighboring DNA fragments, arranging them into a contiguous sequence corresponding to the DNA sequence in the chromosome. Scientists can then determine the location of genes and other markers in these fragments and sequence them.

"Instead of producing a physical map of wheat chromosomes directly, the chromosomes of Aegilops tauschii, one of the three ancestors of wheat and the source of its D genome, will be mapped first," Dvorak said. "These maps will then be used as templates in physical mapping of individual chromosomes of the wheat D genome, which is one of the specific objectives of this project."

While it will take years and further studies before the full wheat genomic sequence will be available to the research community, NSF funders say this project is a vital first step. The project will include sponsoring student internships and workshops for other scientists in fingerprinting and physical mapping as well as creating a public repository of all the data and its analysis.

"The knowledge from this project will be helpful in all aspects of wheat breeding and biotechnology because it will accelerate the discovery and isolation of economically important genes," Dvorak said. "The project will also advance understanding of the evolution and the global organization of large plant genomes."

The project includes UC Davis investigators Ming-Cheng Luo and Patrick McGuire, and Olin Anderson from the U.S. Department of Agriculture/ARS in Albany, Calif., who also holds an adjunct appointment at UC Davis. It also involves Bikram Gill from Kansas State University, Doreen Ware from Cold Spring Harbor Laboratory in New York, and Jaroslav Dolezel from the Institute of Experimental Botany in the Czech Republic.

The NSF began in 1998 making annual grant awards through its Plant Genome Research Program, dedicated to advancing understanding of the structure, organization and function of plant genomes that are important to agriculture, the environment, energy and health.