Construction of Lager brewing yeast DNA microarray and genome wide gene expression analysis during the lager brewing process.
Yoshihiro Nakao (1), Yukiko Kodama (1), Tomoko Fujimura (1), Wataru Miki (1), Takehiko Ito (2), Katsuhiko Shirahige (3), Toshihiko Ashikari (4)
(1) Inst. for Advanced Technology, SUNTORY LIMITED, 1-1-1 Wakayamadai, Osaka, 618-8503, Japan; (2) Mitsubishi Research Institute, INC., 2-3-6, Otemachi, Chiyoda-ku, Tokyo, 100-8141 Japan; (3) Tokyo Institute of Technology, 4259 Nagatsuda, Midori-ku, Yokohama, 226-8501, Japan; (4) Florigene, 16 Gipps Street Collingwood VIC 3066, Australia
DNA microarray is a powerful tool for the elucidation of biological processes and it is therefore very important for its biotechnological applications. Recently S. cerevisiae DNA microarray has been employed to study the metabolic characteristics of other Saccharomyces yeasts, however, it was not sufficient to use this array for lager brewing strains. We have recently sequenced the whole genome of a representative lager brewing strain, Weihenstephan 34/70, and showed that it is composed of two divergent genomes; one that we indicated as S. cerevisiae (Sc) type and the other, with an identity of approximately 85% to S. cerevisiae, that we defined non-S. cerevisiae (non-Sc) genome. When a lager strains is hybridized to the S. cerevisiae microarray most of the non-Sc type ORF are not detected, often providing ambiguous results. Using the genome sequence of the lager strain, we have therefore constructed a DNA microarray specifically for Lager brewing strains (LBYG array) containing both Sc type ORFs and non-Sc type ORFs. We have used this array to analyze the transcriptome of the strain during a pilot-scale lager fermentation. We confirmed that the LBYG array could detect the expression of both Sc and non-Sc genes. During the fermentation 254 non-Sc genes were expressed more than 2 folds than the corresponding Sc type genes. The high expression level of the non-Sc type genes and their industrial implications for the contribution in lager brewing is here discussed.