23. 05. 2017

An international team of scientists has managed after many years of effort to acquire the entire hereditary information of barley, a major cereal that is mainly used as a feed for livestock and for the production of beer and whiskey. The International Barley Sequencing Consortium (IBSC) informed of the success and an article was published on it in the prestigious journal Nature. The Olomouc experts from the Institute of Experimental Botany of the Czech Academy of Sciences (ÚEB), who are partners of the Centre for the Region Haná for Biotechnology and Agricultural Research, also have a share in it.

he full reading of barley’s hereditary information is the result of tens of years of intense work, and it’s the largest genome that scientists have read in such high quality. The task they have mastered was extremely complicated. Barley’s hereditary information is made up of five billion letters, which means it by half greater than that of the human genome. This size is due to the presence of so-called repetitive DNA sequences that make up about eighty percent of the genome. The sequences are repeated in the same form in many places, so it is very difficult to determine their location and assemble them into larger units.

International cooperation was crucial

Without the international cooperation of teams from Germany, Great Britain, China, Australia, Denmark, Finland, Sweden, Switzerland, the USA and also the Czech Republic, it would not have been possible to acquire and process all of the data. The successful use of new technologies, including the so-called Hi-C method, has made a significant contribution. The Centre for Structural and Functional Plant Genomics at the IEB has been involved in reading barley genome from the very beginning. According to the head of the laboratory and coordinator of the programme Food for the Future of Strategy AV21, Professor Jaroslav Doležel, the acquisition of such a high-quality sequence of barley was conditioned by the combination of the classic older techniques and the latest methods of the reading of the genome: “We were one of the main authors of the first version of the barley genome published in 2011, which was obtained using our chromosome isolation method. As a result, the first version of the barley genome was obtained at that time, which greatly accelerated the sequencing process. In recent years, we have been involved in the project with state-of-the-art optical mapping techniques that enable us to solve the problem of compiling areas containing repetitive DNA sequences. Our main input was the preparation of very high-quality DNA, which is indispensable for this method.”

The result will help other scientists and plant breeders

The largest genome ever read in such high quality was the genome of maize, which is, however, only half when compared to barley. Barley also belongs to another group of cereals, and therefore this result will make it easier for scientists to work with reading the wheat and rye genomes. Above all, it will help in breeding new varieties of barley resistant to climate changes, pests and diseases.

According to Professor Jaroslav Doležel, it is a massive step forward: “All at once we have a book available for such a significant crop, which describes in detail its hereditary information. We can look in it for places corresponding to the agronomically important signs and thus substantially accelerate the acquisition of DNA markers for breeding and isolation of significant genes. Now we have new possibilities to reveal how DNA actually affects the appearance of the plant, its reaction to external conditions, and the like.”

The availability of a high-quality sequence of barley will be of great importance in the future in the use of new genome editing methods. It will enable one to find a certain area of hereditary information that will be necessary to modify and with great precision to change the order of the letters in the hereditary information.

Scientists now stand before the challenge to read the genome of another two important cereals, namely wheat and rye. The team of Professor Jaroslav Doležel is also participating in these two prestigious projects. The publication of the full sequence of the wheat genome is still expected this year.

Prepared by: Institute of Experimental Botany of the CAS
Photo: Institute of Experimental Botany of the CAS (in the photographs: Dr. Helena Toegelová and Prof. Jaroslav Doležel).