Draft Genome Sequencing of Buckwheat (Fagopyrum esculentum) and Application for Identifying Agronomically Useful Genes

Buckwheat (Fagopyrum esculentum Moench) is a widely cultivated annual crop in temperate zones in the world. It is nutritionally dense non-model crop contains high levels of starch, proteins, flavonoids, and dietary fiber in the grain. The buckwheat flour is gluten-free and can replace wheat flour in a coeliac diet. The buckwheat genome is outcrossing nature, caused by heteromorphic self-incompatibility (SI), which makes it difficult to produce pure cultivars and to fix useful traits. It is widely known that the grain of buckwheat has allergens which could induce anaphylactic reactions. To attempt to improve the nutritional quality of the grain and removing genes responsible for SI and allergens, we sequenced the genome sequence of buckwheat. In this study, we have determined the draft genome sequence of buckwheat (FES_r1.0) by assembling the Illumina HiSeq 2000 paired-end reads with insert sizes 180 bp and 200 bp and mate-pair reads with insert sizes 3 kbp, 5 kbp, 10 kbp, and 20 kbp. The total length of the scaffold sequences was 1.18 Gbp, and N50 length was 25 kbp. The 35,816 genes were predicted, and their functions were estimated by sequence similarity searches. We identified the genes related to flavonoid biosynthesis, the duplicated genes related to buckwheat allergens, GBSS genes related to starch synthesis, and heteromorphic SI genes. The genomes and genes obtained were distributed from Buckwheat Genome DataBase (BGDB; http://buckwheat.kazusa.or.jp), and the information would be useful for developing superior varieties of buckwheat.