The oat genome provides insights into metabolic diversification in grasses

Oat is a cereal crop that is used for food, feed and forage. It belongs to the Aveneae tribe, which diverged from the Triticeae (the tribe containing the best-characterized temperate cereals, wheat and barley) around 30 million years ago, and from the Panicoideae (maize and sorghum) around 50-60 million years ago. Oat domestication has followed a strikingly different route to these other cereals since oat appears to have become a crop only after several thousand years of dispersal as a weed. Consequently it has a number of distinct agronomic strengths, including high biotic/abiotic stress tolerance, low input requirements, and health-beneficial properties. Here we present a draft sequence for the 4.1 Gb genome of the diploid oat species Avena strigosa. Using flow cytometry we also generated chromosome-specific sequence for chromosome 1, which harbors a 13 gene biosynthetic cluster for the synthesis of antifungal defense compounds known as avenacins, which confer resistance to take-all disease. We show that the avenacin gene cluster is located in a non-sytenic region that has assembled since oats diverged from other cereals and grasses and that has undergone rapid evolution.