Mapping wheat ancestors' genomes to implement valuable traits

Posted April 21, 2016

Wild relatives of wheat contain valuable traits for wheat breeding

If there’s one thing Kansas farmers understand, it’s unpredictability. Unpredictable crop conditions keep farmers on their toes, but what if those farmers had drought tolerant wheat, or maybe even wheat with resistance to common pests?

Kansas wheat farmers are funding research into this resiliency through their investment in the Kansas Wheat Commission. Eduard Akhunov, associate professor in plant pathology at Kansas State University, has been dedicating his time to creating markers for wheat ancestor species genomes to identify valuable genes, like these, which could improve wheat’s resiliency.

Wild relatives of wheat have valuable genes that have resistance to pests, pathogens and stress factors such as temperatures, drought or wind, said Akhunov. However, access to these useful genes in wheat breeding programs is limited because they have not been identified or marked.

“We are trying to use some useful genes that are found in wild ancestors of wheat by transferring them to wheat and then actually putting them into the field,” he said.

According to Akhunov, they characterize a diverse collection of wild ancestors and relatives of wheat in collaboration with colleagues from the Wheat Genetics Resources Center, Department of Agronomy and the KSU Integrated Genomics Facility.

“In total currently we have characterized 30 species. We have used next-generation sequencing technology to sequence their genomes and gather molecular information for all genes in each of these grass species,” said Akhunov.

For plant research, exploring a plant’s genome is key. The genome sequence is like a map, and genes and other functional pieces of genetic code are the landmarks, roads and towns that bring the big picture together. Akhunov’s team first developed a database of functionally important genome sequences of the wild relatives of wheat using high throughput DNA sequencing technology combined with a process called sequence capture. Sequence capture allows for only the functional portion of the plant's genome to be examined for genetic variation.

According to Akhunov, molecular markers are used to mark variations in genome sequences of DNA. These markers allow researchers to pinpoint exactly where in the genome the exact gene for a specific resistant or high-yielding trait is located, much like symbols you’ll see on a map differentiating hospitals from tourist attractions. If researchers find the marker in a genetic sample, they know that the gene is present, long before it would have been expressed when planted in a test plot.

Akhunov said that the project so far has taken about three years and will still need about one year to be fully completed. He said his team has completed making markers for almost all the wild relatives and completed generating all the data. The next step in the project is to convert these markers into easy-to-use assays that will allow characterizing large number of wheat lines at low cost.

“Starting next year, we will start putting plants developed using some of these sequenced ancestors into the field,” said Akhunov. “With our K-State collaborators we will start phenotyping them for drought, disease resistance, and for all the traits. This kind of data will help us to identify genes that control these traits.”

By Audrey Schmitz, Kansas Wheat Communications Intern