Flor strains of Saccharomyces cerevisiae are principal microbial agents responsible for biological wine aging used for production of sherry-like wines. The flor yeast velum formed on the surface of fortified fermented must is a major adaptive and technological characteristic of flor yeasts that helps them to withstanding stressful winemaking conditions and ensures specific biochemical and sensory oxidative alterations typical for sherry wines. We have applied RNAseq technology for transcriptome analysis of an industrial flor yeast strain at different steps of velum development over 71 days under experimental winemaking conditions. Velum growth and maturation was accompanied by accumulation of aldehydes and acetales. We have identified 1490 differentially expressed genes including 816 genes upregulated and 674 downregulated more than 2-fold at mature biofilm stage as compared to the early biofilm. Distinct expression patterns of genes involved in carbon and nitrogen metabolism, respiration, cell cycle, DNA repair, cell adhesion, response to various stresses were observed. Many genes involved in response to different stresses, oxidative carbon metabolism, high affinity transport of sugars, glycerol utilization, sulfur metabolism, protein quality control and recycling, cell wall biogenesis, apoptosis were induced at the mature biofilm stage. Strong upregulation was observed for FLO11 flocculin while expression of other flocculins remained unaltered or moderately downregulated. Downregulated genes included those for proteins involved in glycolysis, transportation of ions, metals, aminoacids, sugars, indicating repression of some major transport and metabolic process at the mature biofilm stage. Presented results are important for in-depth understanding of cell response elicited by velum formation and sherry wine manufacturing conditions, and for the comprehension of relevant regulatory mechanisms. Such knowledge may help to better understand the molecular mechanisms that flor yeasts use to adapt to winemaking environments, establish the functions of previously uncharacterized genes, improve the technology of sherry- wine production, and find target genes for strain improvement.

中文翻译：

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用于生物葡萄酒老化的酵母菌株的转录组概况揭示了弗洛发育过程中基因表达的动态变化。

酿酒酵母（Saccharomyces cerevisiae）的弗洛尔菌株是负责生物葡萄酒老化的主要微生物剂，用于生产雪利酒样葡萄酒。强化发酵葡萄汁表面形成的弗洛酵母膜是弗洛酵母的主要适应性和技术特征，可帮助其承受严苛的酿酒条件，并确保雪利酒典型的特定生化和感官氧化改变。我们已将RNAseq技术应用于在实验酿酒条件下超过71天的膜发育不同步骤的工业花酵母菌株的转录组分析。卵生长和成熟伴随着醛和乙缩醛的积累。我们已经确定了1490个差异表达的基因，其中包括816个基因的上调和674个基因的下调，与早期生物膜相比，在成熟生物膜阶段的表达超过2倍。观察到与碳和氮代谢，呼吸作用，细胞周期，DNA修复，细胞粘附，对各种压力的反应有关的基因的不同表达模式。在成熟的生物膜阶段诱导了许多与不同压力，氧化碳代谢，糖的高亲和力转运，甘油利用，硫代谢，蛋白质质量控​​制和再循环，细胞壁生物发生，细胞凋亡有关的基因。观察到FLO11絮凝蛋白强烈上调，而其他絮凝蛋白的表达保持不变或适度下调。下调的基因包括那些参与糖酵解的蛋白质，离子，金属，氨基酸，糖的转运，表明在成熟生物膜阶段抑制了一些主要的转运和代谢过程。提出的结果对于深入了解由膜形成和雪利酒生产条件引起的细胞反应以及对相关调控机制的理解非常重要。这些知识可能有助于更好地理解花酵母用于适应酿酒环境的分子机制，建立以前未表征的基因的功能，改善雪利酒生产的技术，并找到用于菌株改良的目标基因。提出的结果对于深入了解由膜形成和雪利酒生产条件引起的细胞反应以及对相关调控机制的理解非常重要。这些知识可能有助于更好地理解花酵母用于适应酿酒环境的分子机制，建立以前未表征的基因的功能，改善雪利酒生产的技术，并找到用于菌株改良的目标基因。提出的结果对于深入了解由膜形成和雪利酒生产条件引起的细胞反应以及对相关调控机制的理解非常重要。这些知识可能有助于更好地理解花酵母用于适应酿酒环境的分子机制，建立以前未表征的基因的功能，改善雪利酒生产的技术，并找到用于菌株改良的目标基因。