title: Key role of lipid management in nitrogen and aroma metabolism in an evolved wine yeast strain.
abstract: BACKGROUND
  Fermentative aromas play a key role in the organoleptic profile of young wines. Their production depends both on yeast strain and fermentation conditions. A present-day trend in the wine industry consists in developing new strains with aromatic properties using adaptive evolution approaches. An evolved strain, Affinity™ ECA5, overproducing esters, was recently obtained. In this study, dynamics of nitrogen consumption and of the fermentative aroma synthesis of the evolved and its ancestral strains were compared and coupled with a transcriptomic analysis approach to better understand the metabolic reshaping of Affinity™ ECA5.
  
  
  RESULTS
  Nitrogen assimilation was different between the two strains, particularly amino acids transported by carriers regulated by nitrogen catabolite repression. We also observed differences in the kinetics of fermentative aroma production, especially in the bioconversion of higher alcohols into acetate esters. Finally, transcriptomic data showed that the enhanced bioconversion into acetate esters by the evolved strain was associated with the repression of genes involved in sterol biosynthesis rather than an enhanced expression of ATF1 and ATF2 (genes coding for the enzymes responsible for the synthesis of acetate esters from higher alcohols).
  
  
  CONCLUSIONS
  An integrated approach to yeast metabolism-combining transcriptomic analyses and online monitoring data-showed differences between the two strains at different levels. Differences in nitrogen source consumption were observed suggesting modifications of NCR in the evolved strain. Moreover, the evolved strain showed a different way of managing the lipid source, which notably affected the production of acetate esters, likely because of a greater availability of acetyl-CoA for the evolved strain.
authors: INRA, UMR1083, 34060, Montpellier, France. rollero@supagro.inra.fr.|SupAgro, UMR1083, 34060, Montpellier, France. rollero@supagro.inra.fr.|Universite Montpellier, UMR1083, 34060, Montpellier, France. rollero@supagro.inra.fr.|Lallemand SAS, 31700, Blagnac, France. rollero@supagro.inra.fr.
authors: Stéphanie
authors: S
authors: Rollero
authors: INRA, UMR1083, 34060, Montpellier, France. mouretj@supagro.inra.fr.|SupAgro, UMR1083, 34060, Montpellier, France. mouretj@supagro.inra.fr.|Universite Montpellier, UMR1083, 34060, Montpellier, France. mouretj@supagro.inra.fr.
authors: Jean-Roch
authors: JR
authors: Mouret
authors: INRA, UMR1083, 34060, Montpellier, France. sanchezi@supagro.inra.fr.|SupAgro, UMR1083, 34060, Montpellier, France. sanchezi@supagro.inra.fr.|Universite Montpellier, UMR1083, 34060, Montpellier, France. sanchezi@supagro.inra.fr.
authors: Isabelle
authors: I
authors: Sanchez
authors: INRA, UMR1083, 34060, Montpellier, France. camarasa@supagro.inra.fr.|SupAgro, UMR1083, 34060, Montpellier, France. camarasa@supagro.inra.fr.|Universite Montpellier, UMR1083, 34060, Montpellier, France. camarasa@supagro.inra.fr.
authors: Carole
authors: C
authors: Camarasa
authors: Lallemand SAS, 31700, Blagnac, France. ajulien@lallemand.com.
authors: Anne
authors: A
authors: Ortiz-Julien
authors: INRA, UMR1083, 34060, Montpellier, France. sablayro@supagro.inra.fr.|SupAgro, UMR1083, 34060, Montpellier, France. sablayro@supagro.inra.fr.|Universite Montpellier, UMR1083, 34060, Montpellier, France. sablayro@supagro.inra.fr.
authors: Jean-Marie
authors: JM
authors: Sablayrolles
authors: INRA, UMR1083, 34060, Montpellier, France. dequin@supagro.inra.fr.|SupAgro, UMR1083, 34060, Montpellier, France. dequin@supagro.inra.fr.|Universite Montpellier, UMR1083, 34060, Montpellier, France. dequin@supagro.inra.fr.
authors: Sylvie
authors: S
authors: Dequin
mesh_terms: D005285:Fermentation / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D050356:Lipid Metabolism / Q000187:drug effects* / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology*; D009812:Odorants; D000439:Pentanols / Q000378:metabolism; D025341:Principal Component Analysis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis; D014920:Wine / Q000032:analysis*
chemical_list: D000439:Pentanols; D055549:Volatile Organic Compounds; C029683:isopentyl alcohol; D009584:Nitrogen; C020377:isoamyl acetate