College of Biological and Agricultural Engineering, Jilin University, Changchun, China.
College of Life Sciences, Jilin University, Changchun, China.
Amino Acids. 2022 Feb;54(2):229-240. doi: 10.1007/s00726-021-03105-5. Epub 2021 Nov 27.
It has been widely reported that the addition of trimethylglycine (betaine) decreases osmotic pressure inhibition for cell growth, leading to increased production of amino acids. However, the underlying mechanism is unclear. To determine the global metabolic differences that occur under the addition of trimethylglycine, transcriptome analysis was performed. Transcriptome analysis of Corynebacterium glutamicum JL1211 revealed that 272 genes exhibited significant changes under trimethylglycine addition. We performed Gene Ontology (GO) and KEGG enrichment pathway analyses on these differentially expressed genes (DEGs). Significantly upregulated genes were mainly involved in the regulation of ABC transporters, especially phosphate transporters and sulfur metabolism. The three phosphate transporter genes pstC, pstA and pstB were upregulated by 13.06-fold, 29.80-fold and 30.49-fold, respectively. Notably, the transcriptional levels of the cysD, cysN, cysH and sir genes were upregulated by 81.5-fold, 57.3-fold, 77.6-fold and 125.4-fold, respectively, consistent with assimilatory sulfate reduction under the addition of trimethylglycine. The upregulation of ilvBN and leuD genes might result in increased L-leucine formation. The data indicated changes in the transcriptome of C. glutamicum with trimethylglycine treatment, thus providing a mechanism supporting the application of trimethylglycine in the production of L-leucine and other amino acids by C. glutamicum strains.
已有大量报道表明，添加三甲基甘氨酸（甜菜碱）可降低渗透压对细胞生长的抑制作用，从而导致氨基酸产量增加。然而，其潜在机制尚不清楚。为了确定添加三甲基甘氨酸时发生的全局代谢差异，我们进行了转录组分析。对谷氨酸棒杆菌 JL1211 的转录组分析表明，272 个基因在添加三甲基甘氨酸后表现出显著变化。我们对这些差异表达基因（DEGs）进行了基因本体论（GO）和京都基因与基因组百科全书（KEGG）富集途径分析。显著上调的基因主要参与 ABC 转运蛋白的调控，特别是磷酸盐转运蛋白和硫代谢。三个磷酸盐转运蛋白基因 pstC、pstA 和 pstB 的上调幅度分别为 13.06 倍、29.80 倍和 30.49 倍。值得注意的是，cysD、cysN、cysH 和 sir 基因的转录水平分别上调了 81.5 倍、57.3 倍、77.6 倍和 125.4 倍，这与添加三甲基甘氨酸时的同化硫酸盐还原一致。ilvBN 和 leuD 基因的上调可能导致 L-亮氨酸的形成增加。这些数据表明，三甲基甘氨酸处理后谷氨酸棒杆菌的转录组发生了变化，从而为三甲基甘氨酸在谷氨酸棒杆菌菌株生产 L-亮氨酸和其他氨基酸中的应用提供了机制支持。
