Oat Reference Genome: Insights into a Nutritious Cereal Crop

Cultivated oat (Avena sativa L.) is an ancient crop that was domesticated over 3,000 years ago as a weed in wheat and barley fields. Oat has a low environmental impact, significant health benefits, and the potential to replace animal-based food products. However, a lack of genome resources has prevented the application of modern plant breeding methods.

An international research team, including IPK Leibniz Institute researchers, has published a high-quality reference genome of A. Sativa and its closest wild relatives. This Avena genus resource will aid in leveraging knowledge from other cereal genomes, improving our understanding of basic oat biology, and accelerating genomics-assisted breeding.

Oats are a worldwide crop. It currently ranks seventh in cereal production. In comparison to other cereals, cultivation requires fewer insecticides, fungicides, and fertilizer treatments. Oat has experienced a revival in recent years, particularly through oat milk.

"Oat milk is a very high-quality product that tastes good and serves as a vegan milk substitute," says Dr. Martin Mascher, head of the research group "Domestication Genomics" at IPK Leibniz Institute and one of the study's authors. Unlike wheat and barley, oat is consumed directly. "While barley is used for brewing and wheat for baking bread, oat, in the form of oatmeal, remains very close to the original grain."

Oat belongs to the Poaceae family of grasses, which also includes wheat, rice, barley, common millet, maize, sorghum, and sugarcane. Avena species can be found in the wild in the Mediterranean, the Middle East, the Canary Islands, and the Himalayas.

Oat is a hexaploid, which means that its genome is made up of three sub-genomes donated by three wild Avena species over the last 10 million years.

Individual sub-genomes have also been replaced during the oat's long evolutionary history. As a result, oats have a very complex genome that differs significantly from wheat and barley. "The oat genome is structurally similar to the wheat and barley genomes, but frequent genomic rearrangements in oat have resulted in a mosaic-like genome architecture," explains Dr. Mascher, who is also a member of the German Center for Integrative Biodiversity Research (iDiv).

"It is now possible to link individual genes to agronomic traits in oat for the first time," says Dr. Martin Mascher. The researchers present detailed analyses of gene families implicated in human health and nutrition, adding to the evidence supporting the safety of oats in gluten-free diets, and perform mapping-by-sequencing of an agronomic trait related to water-use efficiency.

With the chromosome rearrangements in a typical spring oat cultivar now identified, breeders and researchers will have access to a resource comparable to the genomes of wheat and barley, which may aid in overcoming breeding barriers caused by a lack of genomic sequence information.

A viable approach for precisely adapting oat varieties is to use the reference genome to map genes associated with agronomic and human nutrition-related traits. "Modern breeding strategies such as genome editing and gene pyramiding can now be applied more easily in oat to develop varieties that meet the increasing global demand for oat-derived products," Dr. Mascher explains.

"After barley, wheat, and rye, the IPK Leibniz Institute has now demonstrated its leadership in the elucidation of genome sequences once again," says Prof. Dr. Nils Stein, head of the IPK research group "Genomics of Genetic Resources" and a co-author of the study.

(Source: European Seed)