Macrowine 2021
IVES 9 IVES Conference Series 9 Influence of nitrogen source on expression of genes involved in aroma production in Saccharomyces uvarum

Influence of nitrogen source on expression of genes involved in aroma production in Saccharomyces uvarum

Abstract

Saccharomyces uvarum has interesting properties that can be exploited for the production of fermented beverages. Particularly, the cryotolerance and capacity to produce high amounts of volatile compounds offers new opportunities for the wine industry. Besides the contribution of the nitrogen source to primary metabolism, some nitrogen compounds are precursors of volatile molecules that produce aroma. The nitrogen compounds assimilated by yeast are classified as rich or poor nitrogen sources depending on how they affect the growth and the nitrogen regulation mechanisms. In S. cerevisiae, the nitrogen metabolism is well understood but less is known about these pathways in S. uvarum. The aim here is to understand the nitrogen metabolism in S. uvarum and the effects of the nitrogen source on the production of aroma volatiles at low temperature; the focus is on temperatures below 20°C since this is relevant for wine production. First, nitrogen preference was established using 10 different compounds as sole nitrogen sources for S. uvarum and S. cerevisiae: important differences were found in the efficiency of asparagine to support growth. The alcoholic fermentations done in synthetic must, showed the same pattern of nitrogen consumption in each species. Afterwards, comparative analysis of gene expression (RNAseq) of S. uvarum MTF3098 was carried out in ammonium, methionine, phenylalanine and asparagine to determine how the nitrogen source affects the expression of key genes involved in nitrogen metabolism and aroma production. The transcriptome data revealed substantial changes in expression patterns of nitrogen metabolism genes. The gene clusters with highest fold change when comparing inorganic nitrogen source (ammonium) and organic source (methionine, phenylalanine, asparagine) in S. uvarum MTF3098 were genes encoding transporters and proteins responsible for aroma synthesis; using amino acids as sole nitrogen source instead of ammonium resulted in an increased expression of this group of genes. This study increases understanding of the importance of the nitrogen source in the aroma production of Saccharomyces yeasts and broads the knowledge on S. uvarum aroma production for applications in wine industry. Ongoing work includes correlating transcriptome and volatile metabolome data to understand links between gene expression and aroma production in S. uvarum.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Angela Coral Medina, Carole CAMARASA, John Morrissey, Darren Fenton

1 SPO, UMR, INRA, SupAgro, Universite de Montpellier, France 2 School of Microbiology, University College Cork, Ireland, SPO, UMR, INRA, SupAgro, Universite de Montpellier, France, School of Microbiology, University College Cork, Ireland, School of Biochemestry and Cell Biology, University College Cork, Ireland

Contact the author

Keywords

saccharomyces uvarum, nitrogen source, gene expression, aroma

Citation

Related articles…

NEAR INFRARED SPECTROSCOPY FOR THE ESTIMATION OF TEMPRANILLO BLANCO VOLATILE COMPOSITION ALONG GRAPE MATURATION

Grape volatile compounds are mainly responsible for wine aroma, so it is important to know the va-rietal aromatic composition throughout ripening process. Currently, there are no tools that allow mea-suring the aromatic composition of grapes, in intact berries and periodically, throughout ripening, in the vineyard or in the winery. For this reason, this work evaluated the use of near infrared spectroscopy (NIR) to estimate the aromatic composition and total soluble solids (TSS) of Tempranillo Blanco berries during ripening. For this purpose, NIR spectra (1100-2100 nm) were acquired from 240 samples of in-tact berries, collected at different dates, from veraison to overripening.

Understanding the complexity of grapevine winter physiology in the face of changing climate

The vast majority of our understanding of grapevine physiology is focused on the processes that occur during the growing season. Though not obvious, winter physiological changes are dynamic and complex, and have great influence on the survival and phenology of grapevines. In cool and cold climates, winter temperatures are a constant threat to vine survival. Additionally, as climate changes, grapevine production is moving toward more traditionally cool and cold climates, either latitudinal or altitudinal in location. Our research focuses on understanding how grapevines navigate winter physiological changes and how temperature impacts aspects of cold hardiness and dormancy. Through these studies, we have gained keen insight into the connections between winter temperature, maximum cold haridness, and budbreak phenology, that can be used to develop prediction models for viticulture in a changing climate.

INSIGHTS ON THE ROLE OF GENES ON AROMA FORMATION OF WINES

Yeast secondary metabolism is a complex network of biochemical pathways and the genetic profile of the yeast carrying out the alcoholic fermentation is obviously important in the formation of the metabolites conferring specific odors to wine. The aim of the present research was to investigate the relative expression of genes involved in flavor compound production in eight different Saccharomyces cerevisiae strains.
Two commercial yeast strains Sc1 (S.cerevisiae x S.bayanus) and Sc2 (S.cerevisiae) and six indigenous S. cerevisiae strains (Sc3, Sc4, Sc5, Sc6, Sc7, Sc8) isolated during spontaneous fermentations were inoculated in Assyrtiko and Vidiano grape must.

Mobilizing endogenous transposable elements for grapevine improvement: a genomic and epigenomic approach in New Zealand Sauvignon Blanc

Efforts to improve the New Zealand wine industry’s climate resilience and sustainability through grapevine improvement are limited by germplasm availability and a reliance on Sauvignon Blanc exports. To address this, we are working to generate a population of 12,000 individuals with unique genetic traits, from which to select future clones for major export varieties.

Sauvignon Blanc plantlets are being regenerated from embryogenic callus, using an approach designed to mobilise endogenous transposable elements as mutagens.

Observatoire Grenache en vallée du Rhône : démarche et premiers résultats après une année d’étude

Face à l’enjeu d’affirmer et de mieux comprendre la spécificité des vins en relation avec leur origine, la notion de « terroir », avec la richesse de sens et la diversité des perspectives qui l’éclairent, se révèle la clef de voûte de la production et de la valorisation de vins personnalisés et typiques. Asseoir la connaissance des principaux terroirs de la Vallée du Rhône sur des bases autres que celles, jusqu’alors essentiellement empiriques, invoquées dans la seconde grande région française productrice de vins d’AOC, constitue un projet conforme à l’intérêt voué à cet enjeu d’actualité.