Daizubase, an integrated soybean genome database including BAC-based physical maps

Soybean [Glycine max (L) Merrill] is one of the most important leguminous crops and ranks fourth after to rice, wheat and maize in terms of world crop production. Soybean contains abundant protein and oil, which makes it a major source of nutritious food, livestock feed and industrial products. In Japan, soybean is also an important source of traditional staples such as tofu, natto, miso and soy sauce. The soybean genome was determined in 2010. With its enormous size, physical mapping and genome sequencing are the most effective approaches towards understanding the structure and function of the soybean genome. We constructed bacterial artificial chromosome (BAC) libraries from the Japanese soybean cultivar, Enrei. The end-sequences of approximately 100,000 BAC clones were analyzed and used for construction of a BAC-based physical map of the genome. BLAST analysis between Enrei BAC-end sequences and the Williams82 genome was carried out to increase the saturation of the map. This physical map will be used to characterize the genome structure of Japanese soybean cultivars, to develop methods for the isolation of agronomically important genes and to facilitate comparative soybean genome research. The current status of physical mapping of the soybean genome and construction of database are presented.