Isolation of a haploid from an industrial Chinese rice wine yeast for metabolic engineering manipulation

Abstract

The complex metabolic processes of yeast influence wine fermentation and therefore the quality of wine. Wine yeasts, owing to their being typically prototrophic and often polyploid, have been restricted in terms of exploiting classical recombinant genetic techniques to improve their characteristics. To overcome this problem, haploids have been isolated from a commercial Chinese rice wine strain N85, by disruption of the HO gene. In this study, the Cre–loxP system and a removable G418r marker were used to construct an HO disruption cassette. Most of the heterologous sequences of constructed disruption cassette were successfully excised from the genome of the haploids by loop-out of the KanMX gene, through induced expression of the Cre recombinase. The removal of the resistant marker ensures the biological safety of the strains. As expected, no difference in fermentation capacity between the parental and the haploid strains was seen. The present work reports the construction of an HO disruption cassette by touchdown polymerase chain reaction and its application with a Chinese rice wine yeast for haploid isolation and to broaden physiological investigations and industrial applications. Copyright © 2013 The Institute of Brewing & Distilling