Sequencing a grain of hope

Between the numerous news reports on cereal shortage and increasing prices, there is a grain of hope for the future of cereal. Researchers have sequenced the genome of Avena sativa, better known as the common oat.

Oat is an important source of food and provides health benefits like reducing cholesterol and blood sugar. Also, growing oat requires less pesticides, has a higher yield and smaller environmental footprint compared to wheat.

Availability of a reference genome for food-bearing crops like oat, makes it a lot easier to locate and identify genes of interest. This facilitates targeted breeding and genetic modifications to improve crop quality. Think about targeting genes that make the crop more resistant to changes in climate, or genes that increase the yield. In a time where cereal shortage is a serious issue in many countries, this brings hope for the future.

In spring 2022, researchers released the sequenced and characterized genome of cultivated oat. Their findings made the cover of Nature. The researchers mapped the genetic information and identified the locations of genes of interest to further our understanding of this crop. With the genetic sequence known, they could investigate specific traits of oat.

In particular, the researchers wanted to understand why oat doesn’t trigger gluten allergies and intolerances as much as wheat or barley. Identification and characterization of the genes encoding gluten proteins showed that oat has expression levels and protein sequences that were more similar to rice than to gluten-rich cereal.

Other interesting findings include the location of a gene that affects the wax composition of the plant. Plants like oat use a wax coating to help them retain water and reflect sunlight, both traits that might prove to be crucial in the context of global warming.

Now that we know what genes are linked to specific traits, and where they can be found on the genome, crop breeders can use this information to breed the oats of the future.

Obtaining all this information was no easy task because oat has a particularly complex genome.  The main reason behind the complexity of the oat genome is its size. The oat genome contains about four times more genes than the human genome. Oat is a hexaploid, meaning it has six sets of chromosomes compared to diploid humans who have only two.

Another reason for the complexity is the mosaic-like structure of the genome. Oat misses a gene that stabilizes the genome in related species like bread wheat. This reduced stability facilitates genomic rearrangements, where parts of the genome move to, or switch places with other parts. Despite its complexity, the entire genome was sequenced.

Now that we know what genes are linked to specific traits, and where they can be found on the genome, crop breeders can use this information to breed the oats of the future. Modern breeding techniques such as genome editing can now be used to focus on specific traits, preparing this grain for challenges brought by climate change and the increasing demand for food.