Genome sequence analysis of high ethyl caproate producing sake yeasts generated by ion beam breeding, 2

Masubuchi, Takashi*; Toguchi, Kazuki*; Hayashi, Hidenori*; Ikenaga, Hiroshi*; Sato, Katsuya; Ono, Yutaka

We conducted the gene function analysis of the high ethyl caproate producing sake yeast mutant (No.227) generated by ion beam breeding in order to develop a new method for sake yeast screening and find factors contributing the reduced ability to alcohol fermentation. The genome sequences of the No.227 and Kyokai 901 (its parental strain) were determined by a whole-genome shotgun strategy using pyrosequencing method. And the determined sequences were compared with that of the sake yeast strain Kyokai 7, which is characterized by the fermentation properties. Consequently, the No.227 carried mutations in the and genes as heterozygous state. It was suggested that these mutations in the and genes in the No.227 might be attributed to the high ethyl caproate production and the low alcohol fermentation ability, respectively.