title: The genetic basis of variation in clean lineages of Saccharomyces cerevisiae in response to stresses encountered during bioethanol fermentations.
abstract: Saccharomyces cerevisiae is the micro-organism of choice for the conversion of monomeric sugars into bioethanol. Industrial bioethanol fermentations are intrinsically stressful environments for yeast and the adaptive protective response varies between strain backgrounds. With the aim of identifying quantitative trait loci (QTL's) that regulate phenotypic variation, linkage analysis on six F1 crosses from four highly divergent clean lineages of S. cerevisiae was performed. Segregants from each cross were assessed for tolerance to a range of stresses encountered during industrial bioethanol fermentations. Tolerance levels within populations of F1 segregants to stress conditions differed and displayed transgressive variation. Linkage analysis resulted in the identification of QTL's for tolerance to weak acid and osmotic stress. We tested candidate genes within loci identified by QTL using reciprocal hemizygosity analysis to ascertain their contribution to the observed phenotypic variation; this approach validated a gene (COX20) for weak acid stress and a gene (RCK2) for osmotic stress. Hemizygous transformants with a sensitive phenotype carried a COX20 allele from a weak acid sensitive parent with an alteration in its protein coding compared with other S. cerevisiae strains. RCK2 alleles reveal peptide differences between parental strains and the importance of these changes is currently being ascertained.
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Darren
authors.initials: D
authors.lastname: Greetham
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Tithira T
authors.initials: TT
authors.lastname: Wimalasena
authors.affiliation: Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Adrian Building, Leicester, Leicestershire, United Kingdom.
authors.forename: Kay
authors.initials: K
authors.lastname: Leung
authors.affiliation: Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Adrian Building, Leicester, Leicestershire, United Kingdom.
authors.forename: Marcus E
authors.initials: ME
authors.lastname: Marvin
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Yogeshwar
authors.initials: Y
authors.lastname: Chandelia
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hart
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Trevor G
authors.initials: TG
authors.lastname: Phister
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Tucker
authors.affiliation: Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Adrian Building, Leicester, Leicestershire, United Kingdom.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Louis
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Smart
mesh_terms: D000220:Adaptation, Biological; D000483:Alleles; D001483:Base Sequence; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal; D003433:Crosses, Genetic; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D008040:Genetic Linkage; D014644:Genetic Variation; D006238:Haploidy; D006579:Heterozygote; D008969:Molecular Sequence Data; D010641:Phenotype; D040641:Quantitative Trait Loci; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013312:Stress, Physiological
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol