A 2-Deoxyglucose-Resistant Mutant of Saccharomyces cerevisiae Shows Enhanced Maltose Fermentative Ability by the Activation of MAL Genes.

MCD4 is a 2-deoxyglucose (2-DOG)-resistant mutant derived from the wild-type strain, AK46, wherein the 2-DOG resistance improves the maltose fermentative ability. In the gene cluster, mutations were detected in and , which encode maltose permeases, and in and , which encode transcriptional activators. In maltose medium, the expression of and in MCD4 was 2.1 and 4.2 times significantly higher than that in AK46, respectively. Besides, the expression of and also tended to be higher than that of AK46. Although no mutations were found in and (which encode α-glucosidases), their expression was significantly higher (4.9 and 4.4 times, respectively) than that in AK46 Since the expression of major catabolite repression-related genes did not show significant differences between MCD4 and AK46, these results showed that the higher maltose fermentative ability of MCD4 is due to the activation of genes encoding two maltose permeases and two α-glucosidases.