Danner Caroline, Mello de Sousa Thiago M, Mach Robert L, Mach-Aigner Astrid R
Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria.
Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria.
Microorganisms. 2025 Mar 4;13(3):584. doi: 10.3390/microorganisms13030584.
The spontaneous loss of cellulase productivity of industrial strains during production results in significant economic losses. This phenomenon was suggested to be epigenetically regulated, but the previous findings did not explain which epigenetic mechanisms occur and how they promote strain degeneration. Until now, the epigenetic landscape of has been poorly understood. This study investigated whether DNA methylation and cellulase production are connected, and, if so, what that connection is and how it relates to strain degeneration. In order to determine what the impact of DNA methylation is on strain degeneration, we induced hypomethylation with hydralazine HCL, which showed a reduced non-productive phenotype and partially restored cellulase productivity. As a second test, we conducted a global DNA cytosine methylation assay, which showed DNA methylation levels of between 0.2 and 1.3% 5-mC. Importantly, non-productive strains exhibited stronger methylation than productive counterparts, and global methylation patterns varied depending on the carbon source. As a final test, we carried out deletion experiments targeting the putative DNA methyltransferases and , which initially reduced the occurrence of a non-producing subpopulation, but subsequent sub-cultivation eliminated cellulase productivity. This study shows that DNA methylation impacts cellulase productivity, an understanding that can help us develop targeted strategies to reduce strain degeneration and improve cellulase production in industrial applications.
工业菌株在生产过程中纤维素酶生产力的自发丧失会导致重大经济损失。有人认为这种现象是由表观遗传调控的，但先前的研究结果并未解释发生了哪些表观遗传机制以及它们如何促进菌株退化。到目前为止，人们对其表观遗传格局了解甚少。本研究调查了DNA甲基化与纤维素酶产生之间是否存在关联，如果存在，这种关联是什么以及它与菌株退化有何关系。为了确定DNA甲基化对菌株退化的影响，我们用盐酸肼诱导低甲基化，结果显示非生产表型减少，纤维素酶生产力部分恢复。作为第二项测试，我们进行了全基因组DNA胞嘧啶甲基化分析，结果显示5 - mC的DNA甲基化水平在0.2%至1.3%之间。重要的是，非生产菌株比生产菌株表现出更强的甲基化，并且全基因组甲基化模式因碳源而异。作为最后一项测试，我们针对假定的DNA甲基转移酶进行了缺失实验，最初减少了非生产亚群的出现，但随后的传代培养消除了纤维素酶生产力。这项研究表明，DNA甲基化会影响纤维素酶生产力这一认识有助于我们制定有针对性的策略，以减少工业应用中的菌株退化并提高纤维素酶产量。
