清酒酵母の一倍体株へのHO遺伝子の導入による二倍体株の分離

概要

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A haploid strain, HL-69,derived from sake yeast Kyokai No. 10(K10), and AOF10,a mutant with low esterase activity toward isoamyl acetate derived from HL-69,were transformed with pAGR-HO-1-a YRp-type plasmid in which both the homothallic switching gene (HO) and alcohol dehydrogenase I-aminoglycoside phosphotransferase II gene (ADH1-APT2) were inserted. Both transformants were resistant to G418 and appeared to be near diploidy. Their cell size was larger than those of their parent strains, AOF10 and HL-69 and they did not form clusters. AOF10-D and HL-69-D, which had lost pAGR-HO-1 under non-selective culture conditions, maintained their diploid-like morphology. Both AOF10-D and HL-69-D had two-fold higher DNA contents per cell than a standard haploid strain, DBY747 ; they had no mating ability but could spolurate. They also had higher CO_2 evolution rates at the final stage of sake brewing than their parent strains. Each sake product brewed with AOF10-D or HL-69-D showed higher alcohol concentration, lower gravity and lower amino acidity than those brewed with their parents AOF10 and HL-69 ; these features were comparable to those of K10. On the other hand, AOF10-D also had low esterase activity, and the sake brewed with this strain contained 1.4-to 2-fold more isoamyl acetate and isobutyl acetate than that brewed with K10. These features of AOF10-D were similar to those of AOF10.
社団法人日本生物工学会の論文
1995-07-25