Exploring the New World of Wheat
Researcher Curtis Pozniak is at the forefront of helping discover the genetic intricacies of a major global crop.
A map is the greatest of all epic poems — its lines and colors show the realization of great dreams. Gilbert Grosvenor, the first editor of National Geographic, said that.
Curtis Pozniak learned the same lesson after helping play a major role in the mapping of the bread wheat genome, a project that could serve to turn the world of wheat on its head.
“I equate it to looking at the sun. It’s such a massive genome, and we’re still in the early stages of analyzing its composition and organization. We now have the genetic blueprint,” says Pozniak, a wheat breeder and professor at the University of Saskatchewan’s Crop Development Centre. “Now comes the real work of deciphering the code to understand how wheat ticks.”
Pozniak co-leads the Canadian Triticum Applied Genomics (CTAG2) project with Andrew Sharpe of the Global Institute of Food Security. In early 2016, Pozniak and his team worked to ensure the entire genome of the Chinese Spring wheat variety was mapped completely and accurately. The variety was selected due to its wide use in genome studies.
Nearly 100 percent of the genome has been mapped, and is available for download through the International Wheat Genome Sequencing Consortium’s (IWGSC) wheat sequence repository at URGI-INRA-Versailles, France.
North American wheat acreage has declined in favor of corn, which had its genome mapped in 2009. Since then, it has enjoyed a renaissance, with the release of a multitude of new varieties that include better stress tolerance, disease resistance and higher yields.
The new wheat genome map is a tool that’s going to do for wheat what’s already been done with corn and other crops, says IWGSC executive director Kellye Eversole.
“We really need to enable the development of next-generation breeding tools, and to do that you really need a sequence. This is long overdue.”
The IWGSC is made up of researchers from across the globe, and Pozniak has been involved since it was formed in 2005.
“At that time, a chromosome-by-chromosome approach was being used, and there was a real need to come together as an international community to get the genome mapped,” says Pozniak. “The vision of the IWGSC to focus on a chromosome-based approach meant that the genome could be tackled in 21 individual pieces.”
For Eversole, that collaborative attitude was key to the project’s success. “Just being involved in something that’s going to help wheat growers is very rewarding. The scientific community has really come together, which has been incredible,” she says.
In the United States, Jesse Poland, a research geneticist with the Department of Agriculture’s Agricultural Research Service at Kansas State University, helped to co-lead the project.
Accounting for more than 20 percent of all calories consumed, the rising global population demands a sustainable and secure source of wheat. This pressures major wheat exporting countries to be at the cutting edge of varietal development.
Wheat researchers across the globe will now have a resource that will allow them to better identify genes responsible for adaptation, pest resistance, stress response and improved yield. But according to Pozniak, sequencing the Chinese Spring genome is just the start of an exciting process of discovery.
“The genome sequence is like a blueprint of all the genes that make up this variety, but the question is, what do each of those genes do, and how are they important for disease resistance and end use quality?” he says. “That will require a significant amount of effort to decipher biology around how that genome is organized, how those genes are expressed, and how they relate to performance in a farmer’s field.”
Poland adds this development sets the stage for a whole new era of wheat breeding, which directly translates to better and faster wheat breeding.
Boon to Industry
Of course, it’s not only farmers who will benefit, but also the makers of products who supply those farmers with the tools they need to grow better crops and a feed a growing world. John Jacobs, a Belgium-based genomics scientist in Bayer’s Crop Science Division, says that for Bayer as a company in the seed and traits industry, the mapping of the wheat genome is extremely valuable.
Jacobs sits on the IWGSC committee as Bayer’s representative.
“We want to increase seed potential, introduce disease resistance and stress tolerance, and for that we need to understand the genetic basis of these traits. We need to know what those underlying genes are and what they do,” he says.
Polland says having a solid reference genome of Chinese Spring wheat will accelerate molecular breeding and genomics.
For instance, Bayer works with thousands of wheat lines, and they each have their own sequence. From this [reference genome], Jacobs says they can go to many genome sequences and look at the differences, find out what they mean and understand the function of everything that’s in that sequence.
He says Bayer is in the early stages of developing a commercial hybrid wheat program. It launched its first wheat variety this year, in Ukraine.
“It’s only in the last six years that we’ve seen a substantial opportunity for wheat,” he says, adding that this renewed focus on wheat was based, in part, on the expected innovations in wheat improvement, which can now be realized even faster with an unlocked wheat genome. Although the IWGSC includes members from around the globe, he credits Pozniak and the Canadian researchers with helping it through its final stretch.
“I think Curtis, his team and Canada in general were especially important in the end, as they secured funding at a moment when there was a breakthrough technology that needed it.”
Funding for wheat genome sequencing project was provided by Genome Canada, Genome Prairie, Saskatchewan Ministry of Agriculture, the Saskatchewan and Alberta Wheat Development Commissions, and the Western Grains Research Foundation through the Canadian Triticum Applied Genomics (CTAG2) project, Kansas State University through the National Science Foundation Plant Genome Research Program, and Illumina, Inc.
Opening the Door
For Pozniak, the door to a new world of wheat has been opened, but scientists like him have yet to truly understand what’s on the other side.
“We’re excited to start comparing how wheat cultivars are different from one another, and understand some of those biological questions about what makes Canadian wheat unique and what makes varieties different from one another at a genomic level,” Pozniak says.
The wheat genome is five times bigger than the human genome and very complex, with three sets of seven chromosomes.
“We’ve already been able to use the data to develop a number of useful molecular tools wheat breeders are using for cultivar development,” Pozniak says. “Ultimately, we can improve breeding efficiency. That doesn’t necessarily mean we will speed up plant breeding, but breeders will be more efficient — and anytime you can do that, it will result in better varieties for our producers.”