An international consortium of scientists, led by Prof. Robbie Waugh of the James Hutton Institute in Scotland, has sequenced the genome of barley, the fourth most commonly cultivated grain in the world. In a paper published in Natureyesterday, the researchers detailed their findings, which will have important applications in combating hunger and adapting to climate change.
Barley is a member of the grass family. Its most common human food use is in beer, but most barley – about three-quarters of the total yield – becomes animal feed. Barley is closely related to wheat but more tolerant of stressful climates and soils, which makes it a more reliable crop in developing countries. Barley’s hardiness and its high concentration of soluble dietary fiber have led to its classification as a “true functional food,” according to the Nature article.
While barley is nutritionally beneficial and agriculturally durable, its genetic structure created obstacles for researchers. Barley is self-pollinating, so the genetic variation in a single field is minimal. Barley has fourteen chromosomes, far fewer than humans have, but the strands are long, making barley’s genome twice the size of the human genome.
The difficulties arose because barley’s DNA is extremely repetitive. When DNA contains a large number of similar sequences, it is harder for researchers to put the genome in order, and easy for them to lose their place. This problem is one of the reasons scientists wanted to sequence barley’s genome: it will help them understand why plants like barley have so many repetitive genes.
Waugh’s team used a number of techniques to compensate for barley’s confusing DNA. Most importantly, they used multiple sequencing, mapping, and anchoring techniques, then compared the results. By comparing several incomplete pictures, the scientists deduced how barley’s genes fit together.
The researchers say that mapping barley’s genome provides insight into the grain’s immune system, helping agricultural scientists understand why barley is more resilient than its relatives. They also observed genetic differences between varieties of barley, which will help breeders select for useful traits and guide farmers to plant the right type of barley for their local climate and terrain.
Robbie Waugh, the leader of the study, expressed optimism for the many applications of his team’s findings. In a news release for the James Hutton Institute, Waugh said, “Access to the assembled catalogue of gene sequences will streamline efforts to improve barley production through breeding for varieties better able to withstand pests and disease and deal with adverse environmental conditions such as drought and heat stress.” He added that this knowledge will aid food scientists in developing barley that can adapt to environmental changes, which will improve food security in vulnerable regions.
Douglas Kell, Chief Executive of the Biotechnology and Biological Sciences Research Council, which funded the sequencing project, sees economic benefits for the United Kingdom and other barley-producing countries. Kell calls the research “an exceptionally valuable step for UK agriculture at a time when we have seen huge losses in the field due to wet weather and price-rise predictions for the consumer.” If barley yields are higher and more reliable, it will be easier to keep food prices stable.
The Nature article does not address the implications for barley’s most familiar use – beer – but both Waugh and Kell imply that the future holds a cheaper, more plentiful pint. Understanding barley’s genome also gives breeders better tools to select for flavor as well as resilience and yield, which means tastier and diverse beers might be on the horizon, too.