Mardanov Andrey V, Eldarov Mikhail A, Beletsky Alexey V, Tanashchuk Tatiana N, Kishkovskaya Svetlana A, Ravin Nikolai V
Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia.
Research Institute of Viticulture and Winemaking "Magarach" of the Russian Academy of Sciences, Yalta, Russia.
Front Microbiol. 2020 Apr 3;11:538. doi: 10.3389/fmicb.2020.00538. eCollection 2020.
Flor strains of 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 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.
弗洛酵母菌株是用于生产类似雪利酒的葡萄酒的生物葡萄酒陈酿的主要微生物制剂。在强化发酵葡萄汁表面形成的弗洛酵母菌膜是弗洛酵母的一个主要适应性和技术特性，有助于它们抵御压力大的酿酒条件，并确保雪利酒特有的特定生化和感官氧化变化。我们应用RNA测序技术对一株工业弗洛酵母菌株在实验酿酒条件下71天内菌膜发育的不同阶段进行转录组分析。菌膜的生长和成熟伴随着醛类和缩醛的积累。我们鉴定出1490个差异表达基因，其中包括在成熟生物膜阶段与早期生物膜相比上调超过2倍的816个基因和下调的674个基因。观察到参与碳和氮代谢、呼吸、细胞周期、DNA修复、细胞黏附、对各种压力反应的基因有不同的表达模式。许多参与应对不同压力、氧化碳代谢、糖的高亲和力转运、甘油利用、硫代谢、蛋白质质量控制和循环利用、细胞壁生物合成、细胞凋亡的基因在成熟生物膜阶段被诱导。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。下调的基因包括参与糖酵解、离子、金属、氨基酸、糖转运的蛋白质的基因，表明在成熟生物膜阶段一些主要的转运和代谢过程受到抑制。所呈现的结果对于深入理解菌膜形成和雪利酒制造条件引发的细胞反应以及理解相关调控机制具有重要意义。这些知识可能有助于更好地理解弗洛酵母适应酿酒环境所使用的分子机制，确定以前未表征基因的功能，改进雪利酒生产技术，并找到用于菌株改良的靶基因。
