title: Mechanism of high trehalose accumulation in a spore clone isolated from Shirakami kodama yeast.
abstract: The intracellular trehalose levels in Shirakami kodama yeast, a strain of Saccharomyces cerevisiae, isolated in 1997 from leaf mold in the Shirakami Mountains and since used as a commercial baker's yeast, are remarkably high, which presumably is related to its tolerance of freezing and drought conditions. We isolated a spore clone from Shirakami kodama yeast with about 1.7-fold higher intracellular trehalose levels than the parental strain and set out to elucidate how this spore clone can accumulate intracellular trehalose to such a high concentration. The gene for trehalose 6-phosphate synthase, TPS1, was duplicated in this spore clone. Both TPS1 genes contributed to the high level of intracellular trehalose as a 3.4-fold decrease resulted from the disruption of one of the two TPS1 genes. Both Msn2 and Msn4, which bind to stress responsive elements in the promoter region of TPS1, were required for production of high levels of trehalose. Furthermore, the neutral trehalase activity of this spore clone is about 3-fold less than that of the laboratory strain although the gene for neutral trehalase, NTH1, functioned normally. These findings indicate that two TPS1 genes and the low trehalase activity are associated with high trehalose accumulation in this spore clone. The wide range of stresses of which we found the spore clone to be tolerant makes this yeast very attractive for commercial application and for further research into the mechanisms underlying stress responses and trehalose metabolism.
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Science, Akita Prefectural University.
authors.forename: Nobushige
authors.initials: N
authors.lastname: Nakazawa
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Obata
authors.forename: Kaori
authors.initials: K
authors.lastname: Ito
authors.forename: Makiko
authors.initials: M
authors.lastname: Oto
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ito
authors.forename: Keitaro
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics; D018628:Gene Dosage / Q000235:genetics*; D020440:Gene Duplication / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005964:Glucosyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D064587:Osmoregulation / Q000235:genetics; D018515:Plant Leaves / Q000382:microbiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D013172:Spores, Fungal / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D014199:Trehalose / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase