Functional characterization of genes required for yeast fitness during fermentation

单细胞酵母Saccharomyces cerevisiae（S.酿酒酵母）是理解保守细胞过程的模式生物，也是工业食品生产的关键微生物。 现代S。酿酒酵母基因组已经进化到能够承受葡萄酒发酵的恶劣环境条件。 然而，大多数S.酿酒酵母基因功能的研究在相对良性的实验室条件下进行，结果，15%的酵母基因仍然没有已知的功能。 细胞代谢的变化，使酵母在发酵过程中的生存也知之甚少。 我的实验室已经评估了所有非必需的S酿酒酵母基因在葡萄汁发酵过程中的作用。 我们已经发现，自噬（字面意思是“自食”），一个细胞吞噬自己的细胞质并回收不需要的细胞器以重新利用必需营养素的过程，对发酵期间的细胞健康很重要。 许多其他基因在发酵条件下对细胞存活产生积极或消极的影响，包括超过50个先前不知道细胞功能的基因。 这项研究提供了一个框架，了解酵母是如何适应发酵，并提出了可能的手段，以提高商业酵母菌株承受发酵过程的能力。 我的NSERC发现资助计划旨在了解发酵过程中自噬如何诱导的机制细节，并为发酵过程中改变适应性的未表征基因提供功能。 这一建议的未来意义包括开发具有改善发酵能力的抗应激葡萄酒酵母菌株。 了解酵母中的抗应激途径可以提高葡萄酒酵母的抗应激能力，提高工业性能，并降低加拿大酿酒厂不完全（缓慢或卡住）发酵的成本。

The unicellular yeast Saccharomyces cerevisiae (S. cerevisiae) is a model organism for understanding conserved cellular processes and is also a key microorganism for industrial food production. The modern S. cerevisiae genome has evolved to withstand the harsh environmental conditions of wine fermentation. However, most studies of S. cerevisiae gene function are performed in relatively benign laboratory conditions and as a result, 15% of yeast genes still have no known function. The changes to cellular metabolism that enable survival of yeast during fermentation are also poorly understood. My lab has assessed the growth of all nonessential S. cerevisiae genes during grape juice fermentation. We have discovered that autophagy (literally, "self-eating"), a process whereby cells engulf their own cytoplasm and recycle unwanted organelles for reuse of essential nutrients, is important for cellular fitness during fermentation. A number of other genes either positively or negatively affect cell survival under fermentation conditions, including over fifty genes with no previously known cellular function. This study provides a framework for understanding how yeast are adapted to fermentation and suggests possible means to improve the ability of commercial yeast strains to withstand the fermentation process. My NSERC Discovery Grant proposes to understand the mechanistic details of how autophagy is induced during fermentation and to provide a function for uncharacterized genes that have altered fitness during fermentation. Future implications of this proposal include developing stress resistant wine yeast strains with improved fermentation capability. Understanding stress resistance pathways in yeast creates potential to increase stress resistance in wine yeast, improve industrial performance and reduce the cost to Canadian wineries of incomplete (sluggish or stuck) fermentations.