Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan; Institute for Research Initiatives, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan.
Institute for Research Initiatives, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan; Department of Food Science and Technology, University of California Davis, One Shields Ave, Davis, CA 95616, USA.
J Biosci Bioeng. 2023 Dec;136(6):438-442. doi: 10.1016/j.jbiosc.2023.10.005. Epub 2023 Nov 7.
Proline, which is a predominant amino acid in grape musts, is involved in the taste and flavor of foods and beverages. The yeast Saccharomyces cerevisiae poorly utilizes proline in wine-making processes, leading to a nitrogen deficiency during fermentation and proline accumulation in wine. Previous studies have shown that the protein kinase A (PKA) pathway is involved in inhibitory mechanisms of proline utilization. In this study, we screened the PKA pathway-related genes that regulate proline utilization. Using a yeast culture collection of disrupted strains associated with the downstream of the PKA cascade, we revealed that the stress-responsive transcription factor genes MSN2/4 regulate proline utilization. Moreover, we found that Msn2/4 up-regulate the SHY1 gene during the cell growth of the wine fermentation model, which may cause the inhibition of proline utilization. The SHY1-deleted strain of the commercial wine yeast clearly showed proline consumption and average ethanol production under the wine fermentation model. The present data indicate that the PKA-Msn2/4-Shy1 cascade controls the inhibition of proline utilization under wine-making processes. Our study could hold promise for the development of wine yeast strains that can efficiently reduce proline during wine fermentation.
脯氨酸是葡萄汁中含量最丰富的氨基酸，参与食品和饮料的味道和风味。酵母酿酒酵母在酿酒过程中对脯氨酸的利用能力较差，导致发酵过程中氮缺乏和葡萄酒中脯氨酸积累。先前的研究表明，蛋白激酶 A (PKA) 途径参与了脯氨酸利用的抑制机制。在本研究中，我们筛选了调节脯氨酸利用的 PKA 途径相关基因。使用与 PKA 级联下游相关的酵母培养物破坏株系的文库，我们揭示了应激响应转录因子基因 MSN2/4 调节脯氨酸利用。此外，我们发现 Msn2/4 在葡萄酒发酵模型的细胞生长过程中上调 SHY1 基因，这可能导致脯氨酸利用的抑制。商业葡萄酒酵母的 SHY1 缺失株系在葡萄酒发酵模型下明显表现出脯氨酸消耗和平均乙醇生产。目前的数据表明，PKA-Msn2/4-Shy1 级联在酿造过程中控制脯氨酸利用的抑制。我们的研究可能为开发能够在葡萄酒发酵过程中有效降低脯氨酸的葡萄酒酵母菌株提供了希望。
