It took 10 years to do it, but researchers at the University of California, Riverside, along with a global team have completed the genome of barley — a key ingredient in beer and single-malt Scotch. The results of their work, which included a team of 77 scientists worldwide, were published in the journal Nature.

In a media release announcing the news, Timothy Close, a professor of genetics at UC Riverside, noted: "This takes the level of completeness of the barley genome up a huge notch. It makes it much easier for researchers working with barley to be focused on attainable objectives, ranging from new variety development through breeding to mechanistic studies of genes."

The work to map barley has value to other "cereal crops" as well, including rice, wheat, rye, maize, millet, sorghum, oats and turfgrass — which, while not a food crop, is in the grass family. Barley has been used for more than 10,000 years as a staple food, for fermented beverages and for animal feed.

The Nature report offers new insights into gene families key to the malting process. Malt is created when barley is allowed to germinate (or sprout). That product is then dried, and it creates needed malt.

The barley genome sequence also helped identify regions of the genome that have been vulnerable to genetic bottlenecking during domestication. This can help researchers optimize genetic diversity in their efforts.

Complicated process
Mapping the barley genome was no easy task. The effort was led by Nils Stein of the Leibniz Institute of Plant Genetics and Crop Plant Research in Germany. The group set out to assemble a complete reference sequence for the barley genome. Trouble is, the barley genome is almost twice the size of the human genome, and 80% of it is composed of highly repetitive sequences, which can't be assigned accurately to specific positions in the genome without considerable effort.

The researchers applied a range of strategies to get past the repetitive sequence issue, and there were major advances in sequencing technology, algorithm design and computing, too. The work kept teams in Germany, Australia, China, the Czech Republic, Denmark, Finland, Sweden, Switzerland, the United Kingdom and the United States busy for 10 years. The work provides knowledge for more than 39,000 barley genes.

During malting, amylase proteins are produced by germinated seeds to decompose energy-rich starch that is stored in dry grains, yielding simple sugars. These sugars then are available for fermentation by yeast to produce alcohol. The genome sequence revealed much more variability than was expected in the genes that encode the amylase enzymes.

Barley is grown throughout the world, with Russia, Germany, France, Canada and Spain being among the top producers. In the United States, barley is mainly grown in the Northwest. Idaho, Montana and North Dakota are the leading producers.

In addition to Close, the following current and former UC Riverside researchers are co-authors of the paper: María Muñoz‐Amatriaín, a project scientist, and Steve Wanamaker, a programmer, both in the Department of Botany and Plant Sciences; Stefano Lonardi, a professor of computer science in the Bourns College of Engineering; and Rachid Ounit, who earned his doctorate earlier this year in computer science after working in Lonardi’s lab.

The UC Riverside team’s contributions were supported by grants from the National Science Foundation and the USDA, and annual support through the UC Riverside Agricultural Experiment Station.

Source: University of California, Riverside