No matter where you go in the world, the dietary customs on every continent all have one thing in common: wheat. Wheat is grown across the globe and in almost every country and is consumed by the majority of the world's population. A newly published paper in Nature aims to increase our collective understanding of how genomic variability amongst this crop has facilitated adaptation to diverse environments and protects this vital food source from insects and diseases.
The study, led by researchers at the University of Saskatchewan, is truly an international effort with close to 100 co-authors from around the world, including researchers Sateesh Kagale, Pierre Fobert and Mulualem Kassa from the Aquatic and Crop Resource Development Research Centre of the National Research Council of Canada (NRC). Their collective goal was to better understand wheat genetics and to share information that could help ensure the success of wheat crops wherever they're grown. To do this, 15 wheat cultivars were selected and sequenced including 2 from Canada.
"Wheat has a very broad adaptability throughout the world," says Kagale. "It has adapted to the specific environmental conditions in each country, which in turn means the genome composition will be different depending on its origin. For example, the environment in Canada is much different than Asia and Australia, so there may be some genetic aspects appearing in different strains. This project was designed to capture that diversity."
"I was involved in a collaborative effort led by Dr. Curtis Pozniak at the University of Saskatchewan's Crop Development Centre in the generation of linked-reads using ChromiumTM technology to enable a more comprehensive view of each genome" explains Kagale. "Assembling a genome using short reads (~250 base-pairs) is very challenging and with wheat this means using billions of pieces to put together a genomic sequence. It is like solving a jigsaw puzzle. We go by similarities at first, like identifying the edges of the puzzle, but then it can get difficult."
The process is known as scaffolding, using it to build a whole chromosome. Using Chromium sequencing, a technology that enables construction of long-range information, researchers are able to stitch the short reads together to assemble the genome.
"Sm1 is the foundation for efforts to minimize damage from this insect in breeding programs worldwide," explains Fobert, Director of Strategic Initiatives with the Aquatic and Crop Resource Research Centre. "The group leveraged information obtained from sequencing wheat genome assemblies to isolate the Sm1 gene, which was shown to encode a protein with nucleotide-binding leucine-rich repeat, kinase, and major sperm protein integrated domains. Their discovery provides diagnostic tools for marker-assisted selection (MAS) and new insights underlying the mechanism of action of Sm1 that will accelerate the development of new crop varieties resistant to the orange wheat blossom midge."
Although the project is large, Kagale says this is just the tip of the iceberg for this collaboration and information will be used in the future to drive many other projects.
"This research is incredibly important and so is the network of researchers that has been created," he says. "This helps us understand genetic diversity of wheat crops and is just the beginning of a network that will grow and expand."