title: Truncation of Gal4p explains the inactivation of the GAL/MEL regulon in both Saccharomyces bayanus and some Saccharomyces cerevisiae wine strains.
abstract: In the past, the galactose-negative (Gal(-)) phenotype was a key physiological character used to distinguish Saccharomyces bayanus from S. cerevisiae In this work, we investigated the inactivation of GAL gene networks in S. bayanus, which is an S. uvarum/S. eubayanus hybrid, and in S. cerevisiae wine strains erroneously labelled 'S. bayanus'. We made an inventory of their GAL genes using genomes that were either available publicly, re-sequenced by us, or assembled from public data and completed with targeted sequencing. In the S. eubayanus/S. uvarum CBS 380(T) hybrid, the GAL/MEL network is composed of genes from both parents: from S. uvarum, an otherwise complete set that lacks GAL4, and from S. eubayanus, a truncated version of GAL4 and an additional copy of GAL3 and GAL80 Similarly, two different truncated GAL4 alleles were found in S. cerevisiae wine strains EC1118 and LalvinQA23. The lack of GAL4 activity in these strains was corrected by introducing a full-length copy of S. cerevisiae GAL4 on a CEN4/ARS plasmid. Transformation with this plasmid restored galactose utilisation in Gal(-) strains, and melibiose fermentation in strain CBS 380(T) The melibiose fermentation phenotype, formerly regarded as characteristic of S. uvarum, turned out to be widespread among Saccharomyces species.
authors: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
authors: Rémi
authors: R
authors: Dulermo
authors: SPO, INRA, SupAgro, Université de Montpellier, 34060, Montpellier, France.
authors: Jean-Luc
authors: JL
authors: Legras
authors: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
authors: François
authors: F
authors: Brunel
authors: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
authors: Hugo
authors: H
authors: Devillers
authors: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
authors: Véronique
authors: V
authors: Sarilar
authors: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France ncecile@grignon.inra.fr.
authors: Cécile
authors: C
authors: Neuvéglise
authors: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
authors: Huu-Vang
authors: HV
authors: Nguyen
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005690:Galactose / Q000378:metabolism*; D005816:Genetic Complementation Test; D005838:Genotype; D053858:Metabolic Networks and Pathways; D018085:Regulon; D012440:Saccharomyces / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014920:Wine / Q000382:microbiology
chemical_list: D004268:DNA-Binding Proteins; C052130:GAL4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D005690:Galactose
keywords: MEL1; Saccharomyces eubayanus; Saccharomyces uvarum; comparative genomics; galactose; melibiose