Wheat is the world’s most cultivated crop, supplying 20 per cent of all calories consumed throughout the world – more than any other food source. It’s estimated that to meet the future demands of a projected world population of 9.6 billion by 2050, wheat productivity needs to increase by 1.6 per cent each year.
A research team led by the University of Saskatchewan (U of S) has played a key role in an international discovery that will have an impact on the food security of millions of people around the world – the sequencing of the billion-piece jigsaw puzzle that is the bread wheat genome.
It’s a discovery that’s expected to bring disruptive innovation to wheat improvement, paving the way for wheat varieties that are better adapted to climate challenges, along with higher yields, disease and pest resistance, and enhanced nutritional quality.
“This breakthrough research means we have a comprehensive blueprint of the wheat genome that will significantly improve the tools breeders have to produce new and better varieties over the long term,” says Curtis Pozniak, researcher and wheat breeder at the U of S Crop Development Centre in the College of Agriculture and Bioresources.
For the past 13 years, more than 200 scientists in 20 countries have been endeavouring, through the International Wheat Genome Sequencing Consortium, to complete the genome sequence for bread wheat and make publicly available the new genomic assembly for breeders.
Computing technology enables speedier genome sequencing
Last August, the journal Science published the highest-quality genome sequence ever produced for the bread wheat variety Chinese Spring.
Dr. Pozniak led Canada’s contribution to the wheat genome initiative through the Canadian Triticum Applied Genomics (CTAG2) project, which also includes scientists from the National Research Council, Agriculture and Agri-Food Canada, the University of Guelph and the University of Regina.
“Essentially we have completed the genome jigsaw puzzle with all the pieces put together in their correct positions and order, providing an enormous advantage in time and effort for breeders when searching for genes that control important traits in the crop,” says Dr. Pozniak. “What once took years to do can now be done in a matter of weeks.”
This had long been considered an almost impossible task. The wheat genome is five times larger than the human genome and more complex, with most of the genome composed of identical repeated elements. Picture a billion-piece jigsaw puzzle, with the added challenge that 90 per cent of the pieces look essentially the same – such as blue sky with a sprinkling of clouds.
Originally, consortium scientists were laboriously mapping wheat’s 21 chromosomes chromosome by chromosome. That’s when Dr. Pozniak and CTAG2 co-lead Andrew Sharpe came up with the idea of using cutting-edge computing technology for speedier genome sequencing. They had previously worked with Israeli company NRGene which had developed new DNA assembly software programs.
“The chromosome-by-chromosome approach would have worked, but it’s very, very time-consuming,” says Dr. Pozniak.
Within three months, the team had a framework sequence for the entire genome. Combining that with already generated data enabled researchers to identify the precise location of 107,891 genes and more than four million molecular markers, as well as how and when the genes are expressed.
“This is the full, uninterrupted genome sequence rather than the fractured picture available previously,” says Dr. Sharpe, director of genomics and bioinformatics at the U of S Global Institute for Food Security (GIFS).
“This resource will have immediate application in the wheat breeding program at the U of S Crop Development Centre where we will see the impact over the next few years,” he adds.
Essentially we have completed the genome jigsaw puzzle with all the pieces put together in their correct positions and order, providing an enormous advantage in time and effort for breeders when searching for genes that control important traits in the crop.— Dr. Curtis Pozniak Researcher and wheat breeder at the U of S Crop Development Centre in the College of Agriculture and Bioresources
Leading large-scale initiative on global food security
Maurice Moloney, executive director of GIFS at the U of S, said this discovery will have a major impact on global food security.
“In light of climate change, water shortages and limitations on the availability of arable land, we will need to rely on plant genetics to increase wheat productivity,” says Dr. Moloney. “Solving the massive puzzle of the wheat genome will go a long way towards accomplishing that, similar to the growth that was made in maize and rice crops after their genomes were assembled.”
The U of S team now leads a larger-scale international initiative to sequence more than 10 cultivated wheat varieties from the main growing areas across the globe. Led by Dr. Pozniak, the 10+ Wheat Genomes Project began last year and uses the same NRGene technology to sequence these genomes, with several varieties already complete.
“To understand what genes do in wheat plants, you need multiple sequences so you can start comparing variants to see what makes them unique. You can then associate these differences with important traits that we select in breeding programs,” says Dr. Pozniak. “By the fall of next year, we expect a complete catalogue of variations and an understanding of how those impact a crop in the field.”
In Canada, wheat accounts for more than $4.5-billion in annual sales and, when value-added processing is factored in, contributes more than $11-billion each year to the Canadian economy.
U of S vice-president Research Karen Chad says the discovery highlights the importance of international research collaboration, noting researchers at IPK Gatersleben in Germany, Kansas State University in the U.S., Tel Aviv University in Israel, and Illumina Inc. were involved.
“No single researcher, university or country can solve global challenges like global food security,” she says. “Working together with our international partners and funding agencies, the complex set of genetic instructions encoded in wheat DNA are now known and breeders will soon have the tools they need for transformative crop innovations.”
The CTAG2 project is funded by Genome Canada, Genome Prairie, Western Grains Research Foundation, and the Saskatchewan Ministry of Agriculture, as well as the Saskatchewan Wheat Development Commission, the Alberta Wheat Commission, and the Canada First Research Excellence Fund through the “Designing Crops for Global Food Security” initiative at the UofS.
Produced by Randall Anthony Communications. The Globe’s editorial department was not involved in its creation.