title: Reconstruction of thermotolerant yeast by one-point mutation identified through whole-genome analyses of adaptively-evolved strains.
abstract: Saccharomyces cerevisiae is used as a host strain in bioproduction, because of its rapid growth, ease of genetic manipulation, and high reducing capacity. However, the heat produced during the fermentation processes inhibits the biological activities and growth of the yeast cells. We performed whole-genome sequencing of 19 intermediate strains previously obtained during adaptation experiments under heat stress; 49 mutations were found in the adaptation steps. Phylogenetic tree revealed at least five events in which these strains had acquired mutations in the CDC25 gene. Reconstructed CDC25 point mutants based on a parental strain had acquired thermotolerance without any growth defects. These mutations led to the downregulation of the cAMP-dependent protein kinase (PKA) signaling pathway, which controls a variety of processes such as cell-cycle progression and stress tolerance. The one-point mutations in CDC25 were involved in the global transcriptional regulation through the cAMP/PKA pathway. Additionally, the mutations enabled efficient ethanol fermentation at 39 °C, suggesting that the one-point mutations in CDC25 may contribute to bioproduction.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan.|Japan Society for the Promotion of Science, Sakyo-ku, Kyoto, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Satomura
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Miura
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Kuroda
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Ueda
mesh_terms: D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D016681:Genome, Fungal; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D059014:High-Throughput Nucleotide Sequencing; D017354:Point Mutation; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D000071436:Thermotolerance; D059467:Transcriptome; D020666:ras-GRF1 / Q000235:genetics* / Q000378:metabolism
chemical_list: C542351:CDC25 protein, S cerevisiae; C112591:HSP12 protein, S cerevisiae; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D020666:ras-GRF1; D000431:Ethanol; D000242:Cyclic AMP; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; D017868:Cyclic AMP-Dependent Protein Kinases; D005947:Glucose; D005690:Galactose