Shandong Provincial Engineering and Technology Research Center for Wild Plant Resources Development and Application of Yellow River Delta, College of Biological and Environmental Engineering, Shandong University of Aeronautics, Binzhou, 256600, China.
Shandong Qianfa Agricultural Technology Co., Ltd, Binzhou, 256600, China.
BMC Microbiol. 2024 Sep 28;24(1):370. doi: 10.1186/s12866-024-03498-9.
Oenococcus oeni is a commercial wine-fermenting bacterial strain, owing to its high efficiency of malolactic fermentation and stress tolerance. The present study explored the function of key genes in O. oeni to enhance stress resistance by heterologous expression of these genes in another species.
The orf00404 gene that encodes a two-component signal transduction response regulator in O. oeni was heterologously expressed in Lactiplantibacillus plantarum WCFS1. The expression of orf00404 significantly enhanced the growth rate of the recombinant strain under acid stress. At 60 h, 72 h, and 108 h of culture at pH 4.0, the recombinant strain had 1562, 641, and 748 differentially expressed genes compared to the control strain, respectively. At all three time points, 20 genes were upregulated in the recombinant strain, including the lamA-D operon-coding genes of the quorum-sensing two component signal transduction system and the spx5 RNA polymerase-binding protein coding gene, which may help adaptation to acid stress. In addition, 47 genes were downregulated in the recombinant strain at all three time points, including the hsp1 heat shock protein-coding gene, the trxA1 thioredoxin-coding gene, and the dinP, mutY, umuC, and uvrB DNA damage repair-related protein-coding genes, potentially indicating that the recombinant strain was less susceptible to stress and had less DNA damage than the control strain in acid stress conditions. The recombinant strain had higher membrane fluidity, permeability, and integrity at an early stage of logarithmic growth (72 h), suggesting that it had a more complete and active cell membrane state at this stage. The intracellular ATP content was significantly reduced in the recombinant strain at the beginning of logarithmic growth (60 h), implying that the recombinant strain consumed more energy at this stage to resist acid stress and growth.
These results indicated that the recombinant strain enhances acid stress tolerance by regulating a gene expression pattern, increasing ATP consumption, and enhancing cell membrane fluidity, membrane permeability, and membrane integrity at specific growth stages. Thus, the recombinant strain may have potential application in the microbial biotechnology industry.
酒香酵母是一种商业葡萄酒发酵菌株，由于其高效的苹果酸-乳酸发酵和应激耐受能力而受到关注。本研究通过在另一种物种中异源表达这些基因来探索 O. oeni 中关键基因的功能，以增强其应激抗性。
在酒香酵母中编码双组分信号转导响应调节蛋白的 orf00404 基因在植物乳杆菌 WCFS1 中进行了异源表达。orf00404 的表达显著提高了重组菌株在酸胁迫下的生长速率。在 pH 值为 4.0 时，培养 60、72 和 108 小时后，与对照菌株相比，重组菌株分别有 1562、641 和 748 个差异表达基因。在所有三个时间点，重组菌株中有 20 个基因上调，包括群体感应双组分信号转导系统的 lamA-D 操纵子编码基因和 spx5 RNA 聚合酶结合蛋白编码基因，这可能有助于适应酸胁迫。此外，在所有三个时间点，重组菌株中有 47 个基因下调，包括 hsp1 热休克蛋白编码基因、trxA1 硫氧还蛋白编码基因以及 dinP、mutY、umuC 和 uvrB DNA 损伤修复相关蛋白编码基因，这可能表明重组菌株在酸胁迫下比对照菌株更不易受到应激和 DNA 损伤的影响。在对数生长期早期（72 小时），重组菌株的膜流动性、通透性和完整性更高，表明该阶段其细胞膜状态更完整、更活跃。在对数生长期开始时（60 小时），重组菌株的细胞内 ATP 含量显著降低，这意味着该重组菌株在该阶段消耗更多的能量来抵抗酸胁迫和生长。
这些结果表明，重组菌株通过调节基因表达模式、增加 ATP 消耗以及在特定生长阶段提高细胞膜流动性、通透性和完整性来增强耐酸能力。因此，该重组菌株在微生物生物技术行业可能具有潜在的应用前景。
