Kansas State University researchers continue to uncover the complexity of the wheat genome, recently publishing the results of a study that characterized many genes duplicated thousands of years ago to understand how they control wheat yield and other desirable traits.
wheat geneticist Edward Akhunovdirector of K-State’s Wheat Genetic Resources Center, said his team’s research could lead to greater opportunities for breeders to perform “targeted breeding” that can increase grain size and number – increasing ultimately yields.
Akhunov said the researchers investigated the role of gene copies available from each of the respective genomes in polyploid crops, those that contain more than two sets of chromosomes, in forming key agronomic traits.
Bread wheat, he added, is polyploid, formed almost 10,000 years ago by the fusion of the genomes of two wild ancestors: tetraploid wild emmer wheat (which has a genomic formula known as AB ) and diploid goatgrass (with genomic formula D).
“As a result,” Akhunov said, “most wheat genes exist in three copies, one each of genomes A, B, and D.”
“This genetic redundancy creates a number of possibilities for interactions between genes and has, over time, contributed to new adaptations, making wheat capable of growing and producing cereals in more diverse climatic conditions,” he said. he declared.
In the current study, K-State researchers tested combinations of gene copies to see what impact they would have on wheat growth and productivity.
“Normally, gene copies of each of the (three) respective wheat genomes are expressed in equal proportions,” Akhunov said. “But we found that there is a relatively small subset of genes in which copies of different wheat genomes are expressed at different levels,” so-called unbalanced gene expression.
Unbalanced gene expression, he added, has been shown to have a positive effect on the wheat plant, in many cases increasing grain size, weight and number.
“Our study suggests that for many years breeders have selected unbalanced gene combinations that have positively impacted yield in various climatic environments,” Akhunov said.
Important for wheat growers: Breeders could use this knowledge to develop new, high-yielding wheat varieties that can grow in a variety of climates.
According to an article from the National Center for Biotechnology Information, polyploidy is a “major force in the evolution of wild and cultivated plants”. Scientists believe that polyploid organisms exhibit increased vigor and, in some cases, surpass their diploid relatives in several respects.
K-State’s work on this project is summarized in the February 11 issue of Communication Nature.
Akhunov said the research represents a major effort led by his research lab in collaboration with the Wheat Coordinated Agricultural Project and funded by the USDA National Institute of Food and Agriculture and the Bill and Melinda Gates Foundation.
The project was part of the International Wheat Yield Partnership, in which wheat researchers around the world cooperate to find solutions to increase wheat yields.