An international consortium enlisting 80 researchers from 12 countries, including those at Kazusa DNA Research Institute, Tottori University, and Okayama University, has used the latest long-read technology to decode the genome of barley with high precision. The consortium has revealed that the structure of genes related to beer brewing, disease resistance, and other functions varies among varieties. The study was published in Nature.
The genome sequence of barley (Hordeum vulgare) is huge, consisting of about 5 billion base pairs, which is 1.7 and 13 times larger than the human and rice genomes, respectively. Thus, it is not easy to decode the barley genome sequence with high precision, and the development of high-precision sequence analysis technology has been awaited to determine the genome and gene sequences of the many varieties preserved worldwide.
The consortium developed gene identification and genetic distinction techniques based on the precise sequence of a single variety, which was overlaid with the sequence of another variety. Moreover, they conducted a pangenome analysis, in which 20 wild and domesticated barley genomes were individually decoded to obtain a compendium of barley DNA sequences.
In the present analysis, the partial genome sequences of more than 20,000 domesticated and wild barley varieties, including those collected and provided by researchers of Okayama University, were used for genetic distinction, and 76 varieties representing barley varieties collected worldwide were selected. The genomes of these 76 varieties were individually decoded using the latest long-read technology to obtain sequences of individual genes on a chromosome-by-chromosome basis. These highly precise sequences were used to correct errors in the gene sequences of 20 varieties that had already been published. Furthermore, they also used the additional genome sequence information from 1315 varieties obtained using conventional methods to confirm the diversity of barley varieties used in breeding. By comparing these decoded varieties, new variants of disease-resistance genes and an increase in the number of genes were found.
Changes in the number of starch-cleaving enzyme genes required for brewing were associated with changes in enzymatic activity used in beer brewing. These results suggest that crop adaptation to and selection by agricultural environments and industrial uses may have resulted in complex changes in the number and structure of genes in the genome.
The continued research, in accordance with these findings, is expected to allow for molecular breeding of barley and the development of new breeding techniques for efficiently developing desired varieties.
Journal Information
Publication: Nature
Title: Structural variation in the pangenome of wild and domesticated barley
DOI: 10.1038/s41586-024-08187-1
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