SPO, INRA, Montpellier SupAgro, Univ Montpellier, Montpellier, France.
PLoS One. 2019 Apr 25;14(4):e0215870. doi: 10.1371/journal.pone.0215870. eCollection 2019.
Nitrogen composition of the grape must has an impact on yeast growth and fermentation kinetics as well as on the organoleptic properties of the final product. In some technological processes, such as white wine/rosé winemaking, the yeast-assimilable nitrogen content is sometimes insufficient to cover yeast requirements, which can lead to slow or sluggish fermentations. Growth is nevertheless quickly restored upon relief from nutrient starvation, e.g. through the addition of ammonium nitrogen, allowing fermentation completion. The aim of this study was to determine how nitrogen repletion affected the transcriptional response of a Saccharomyces cerevisiae wine yeast strain, in particular within the first hour after nitrogen addition. We found almost 4800 genes induced or repressed, sometimes within minutes after nutrient changes. Some of these responses to nitrogen depended on the TOR pathway, which controls positively ribosomal protein genes, amino acid and purine biosynthesis or amino acid permease genes and negatively stress-response genes, and genes related to the retrograde response (RTG) specific to the tricarboxylic acid (TCA) cycle and nitrogen catabolite repression (NCR). Some unexpected transcriptional responses concerned all the glycolytic genes, carbohydrate metabolism and TCA cycle-related genes that were down-regulated, as well as genes from the lipid metabolism.
葡萄醪的氮组成会影响酵母的生长和发酵动力学，以及最终产品的感官特性。在某些工艺过程中，如白葡萄酒/桃红葡萄酒酿造，酵母可利用氮含量有时不足以满足酵母的需求，这可能导致发酵缓慢或迟滞。然而，通过添加铵态氮等方式缓解营养饥饿后，生长会迅速恢复，从而完成发酵。本研究旨在确定氮的补充如何影响酿酒酵母菌株的转录反应，特别是在氮添加后的第一个小时内。我们发现，几乎有 4800 个基因被诱导或抑制，有时在营养物质变化后的几分钟内。这些氮响应中的一些依赖于 TOR 途径，该途径正向调节核糖体蛋白基因、氨基酸和嘌呤生物合成或氨基酸渗透酶基因，负向调节应激反应基因，以及与三羧酸 (TCA) 循环和氮分解代谢阻遏 (NCR) 特异性的逆行反应 (RTG) 相关的基因。一些出乎意料的转录反应涉及所有糖酵解基因、碳水化合物代谢和与 TCA 循环相关的基因下调，以及脂质代谢基因。
