K-State part of effort to completely sequence common wheat genome

Kansas State University and the Kansas Wheat Commission are spearheading the effort to create the Wheat Genome Sequencing Consortium, an international program focused on building the foundation for advancing agricultural research for wheat production.

The principal goal of the consortium is to obtain a publicly available, complete sequence of common (hexaploid) wheat since it is grown on more than 95 percent of the wheat-growing-area worldwide.

Bikram Gill, university distinguished professor of plant pathology at K-State and the U.S. co-chair of the consortium, said wheat should be next in line for the sequencing process. “Among the three major crops: rice, maize and wheat, the rice and maize genomes have already been sequenced,” he said. “Right now, there is very little effort for wheat and it is getting behind. The reason is that the wheat genome is very large. It is 40-times larger than the rice genome and six-times larger than the maize genome.”

The complete sequence of common wheat holds the key to genetic improvements that will allow growers to meet the growing demand for high-quality food produced in an environmentally sensitive, sustainable and profitable manner, he said.

Gill said understanding the sequencing process is as important to understanding wheat genomes as learning the alphabet is in learning the English language. “Essentially, there are four chemical letters called bases — A, C, G and T — in the DNA code that controls wheat genetic traits,” he said. “There are 16 billion base pairs in wheat. To learn the language of genetic traits we must determine the exact sequence of the four letters in the wheat genomes.”

In the future, members of the consortium will begin identifying all 16 billion sequences, but for now the program is in the process of plotting out physical maps of small sequences. This is just one of the short-term goals laid out by the consortium.

The organization believes that its goal of obtaining a complete sequence of common wheat for a reasonable price is achievable in the foreseeable future. In late 2003, the cost of obtaining coverage of a genome equivalent in size to the human genome was approximately $45 million. Within 18 months, the cost was less than $18 million at any of the large sequencing centers. New sequencing methods that are under development may reduce further sequencing costs in the future, Gill said.