Futagami Taiki, Goto Masatoshi
Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima, Japan.
United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan.
Commun Integr Biol. 2022 Mar 16;15(1):92-95. doi: 10.1080/19420889.2022.2051844. eCollection 2022.
White koji, a solid-state culture of mut. using grains such as rice and barley, is used as a source of amylolytic enzymes and citric acid for the production of shochu, a traditional Japanese distilled spirit. We previously characterized changes in gene expression that affect the properties of white koji during the shochu production process; however, the underlying regulatory mechanisms were not determined. We then characterized the NAD-dependent histone deacetylase sirtuin, an epigenetic regulator of various biological phenomena, in . mut. and found that sirtuin SirD is involved in expression of α-amylase activity and citric acid accumulation. In this addendum study, we measured the NAD/NADH redox state and found that the NAD level and NAD/NADH ratio decrease during koji production, indicating that sirtuin activity declines in the late stages of koji culture. By comparing these results with transcriptomic data obtained in our previous studies, we estimate that approximately 35% of the gene expression changes during white koji production are SirD dependent. This study provides clues to the mechanism of gene expression regulation in . mut. during the production of white koji.
白曲是利用大米和大麦等谷物对米曲霉进行固态培养得到的产物，用作淀粉酶和柠檬酸的来源，用于生产日本传统蒸馏酒烧酒。我们之前已对烧酒生产过程中影响白曲特性的基因表达变化进行了表征；然而，其潜在的调控机制尚未确定。随后，我们对烟酰胺腺嘌呤二核苷酸（NAD）依赖性组蛋白脱乙酰酶沉默调节蛋白（一种参与多种生物学现象的表观遗传调节因子）在米曲霉中的特性进行了表征，发现沉默调节蛋白SirD参与α-淀粉酶活性的表达和柠檬酸的积累。在本补充研究中，我们测量了NAD/NADH氧化还原状态，发现曲生产过程中NAD水平和NAD/NADH比值下降，这表明沉默调节蛋白活性在曲培养后期下降。通过将这些结果与我们之前研究中获得的转录组数据进行比较，我们估计白曲生产过程中约35%的基因表达变化依赖于SirD。本研究为米曲霉在白曲生产过程中的基因表达调控机制提供了线索。
