News this week of a “shotgun sequence” of the wheat genome inspired excitement about the possibilities for breakthrough science based on increased understanding of the crop’s complex genetic make-up.
Sequencing the wheat genome has been a long-term goal of many leading wheat researchers and wheat farmers. The large size of the wheat genome, more than five times the size of the human genome, poses a huge and expensive scientific challenge and creates hurdles for crop improvement for wheat. Unlocking the wheat genome will have a global impact since one-fifth of calories consumed by the earth’s people come from wheat.
An article published this week in Nature described the results of a large, international collaboration to further understand the wheat genome using a “shotgun sequencing approach”.
The “shotgun sequencing approach” involved first identifying millions of DNA fragments and then piecing them together to identify nearly 100,000 genes in common wheat. Two-thirds of the genes identified were able to be assigned to the three component genomes of hexaploid wheat.
However, gaps remain in the sequence, and it is not anchored to a genetic map of agronomic traits. The project to create a complete sequence anchored to a map has been underway for some time by an international team of scientists but is not fully funded, which has delayed progress.
Researchers are searching for genetic keys that will help them breed better, higher-yielding varieties. This potential could be realized by identifying sources of genetic diversity within wheat ancestors and relatives or by mapping additional landmarks for important traits within today’s wheat. The research unveiled this week identified expanded gene families that could be associated with higher yield.
“This is an excellent piece of research to identify most of the genes in wheat,” said P. Stephen Baenziger, a wheat breeder at the University of Nebraska and the chair of the National Wheat Genomics Committee.
“It is a major step forward but also highlights how much further we need to go to fully utilize the wheat genome for crop improvement. The full sequence is needed so we can know the location of the key genes and how the sequence relates to the genome function.”
The effort announced this week included researchers from the United Kingdom, Germany and the United States. U.S. collaborators included researchers at USDA’s Agricultural Research Service (ARS), Cold Spring Harbor Laboratory, University of California-Davis, Kansas State University and North Dakota State University.
Jan Dvorak of UC-Davis and a study co-author, noted in a release that “this work moves us one step closer to a comprehensive and highly detailed genome sequence for bread wheat.”
Another of the study’s co-authors, Bikram Gill, who is the director of the Kansas State Wheat Genetics Resource Center, said, “Scientists now have a genetic blueprint of common wheat for many traits, although associating gene sequences with traits will take many more years of work.”
The full paper released this week is available online at http://www.nature.com/nature/journal/v491/n7426/full/nature11650.html.