GENOMIC RESOURCES: MOVING WHEAT INTO THE MAINSTREAM IN PLANT GENOMICS

Authors: Gustafson, J; MCGUIRE, PATRICK - UNIV OF CALIFORNIA-DAVIS; QUALSET, CALVIN - UNIV OF CALIFORNIA-DAVIS

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2004
Publication Date: 11/1/2004
Citation: Gustafson, J.P., Mcguire, P.E., Qualset, C.O. 2004. Genomic resources: moving wheat into the mainstream in plant genomics. Genetics. 168:583-584.

Interpretive Summary:

Technical Abstract: Genome analysis was used in the 1950s to establish the evolutionary and homoeologous relationships of the three genomes (AA, BB, and DD) of hexaploid wheat (Triticum aestivum L.). Each of the 21 pairs of chromosomes was identified and characterized with respect to genomic and homoeologous relationships. A vast array of genetic resources was developed including monosomic, nulli-tetrasomic, ditelosomic, and terminal deletion stocks. When molecular mapping became a reality these stocks were used to complement hybridization-based segregating populations for recombination mapping. In 1989, an international effort was launched, the International Triticeae Mapping Initiative (ITMI), to assure that public maps and genetic stocks would be available as a public good. Scientists in several countries utilized a single mapping population and did RFLP mapping. While RFLP mapping provided chromosome locations, physical mapping was not possible. It became clear that resources, such as ESTs, for functional genomics were the next critical need. Thus, ITMI spawned the International Triticeae EST Cooperative (ITEC) whereby developers of ESTs pooled and shared some 24,000 ESTs. Next, a group of US scientists proposed the large-scale development of ESTs and the mapping of unigenes to chromosome bins defined by a set of deletion stocks. This project "The Structure and Function of the Expressed Portion of the Wheat Genomes," known as wEST, was funded by NSF Plant Genome Program along with support of the collaborating institutions. This effort engaged the participation of 14 investigators at 10 institutions who had defined functions: cDNA library development, EST production, deletion stock characterazation and mapping, and coordination of individual chromosome maps. The ESTs are available from the Wheat Genomics Resource Repository (USDA and University of California, Davis, website: http://wheat.pw.usda.gov/wgc/) and the Arizona Genomics Institute (website: http://genome.arizona.edu). No intellectual property rights were assigned to the ESTs. Discoveries emanating from specific ESTs may be subject to intellectual property rights, depending on the investigators' institutional policies. Ten manuscripts from the above research provide documentation for the development of a substantial genomics resource base for wheat: i) 37 cDNA libraries capturing a large portion of genes expressed during wheat plant development; ii) a collection, database, and analysis tools for more than 100,000 ESTs; and iii) a database of some 8,000 deletion-mapped ESTs. These data have already been used to assess wheat-rice comparative synteny and analysis of the organization of wheat chromosomes and their evolution. The project provided training opportunities for approximately 160 high school, undergraduate, graduate, and post-doctoral scholars who contributed to the success of the project. The project's ESTs were the first large-scale public wheat ESTs (about 25% of the international NCBI inventory of wheat ESTs) and have stimulated wheat sequencing and mapping efforts worldwide. This resource is being used as a source of genes for high-resolution mapping of wheat chromosome regions, for marker-assisted selection, comparative genomics, and a systematic survey for single-nucleotide polymorphisms. This research will ultimately improve our understanding of wheat and how to use this knowledge to improve world food production.