Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China.
J Sci Food Agric. 2021 Dec;101(15):6578-6585. doi: 10.1002/jsfa.11292. Epub 2021 May 14.
Streptococcus thermophilus, one of the most important lactic acid bacteria, is widely used in food fermentation, which is beneficial to improve food quality. However, the current genetic transformation systems are inefficient for S. thermophilus S-3, which hinders its further study.
We developed three electroporation transformation methods for S. thermophilus S-3, and optimized various parameters to enhance the transformation efficiency up to 1.3 × 10 CFU/μg DNA, which was 32-fold higher than that of unoptimized. Additionally, transcriptional analysis showed that a series of competence genes in S. thermophilus S-3 were remarkedly up-regulated after optimization, indicating that improvement of transformation efficiency was attributed to the expression level of competence genes. Furthermore, to prove their potential, expression of competence genes (comEA, cbpD and comX) were employed to increase transformation efficiency. The maximum transformation efficiency was obtained by overexpression of comEA, which was 14-fold higher than that of control.
This is the first report of competence gene expression for enhancing transformability in S. thermophilus, which exerts a positive effect on the development of desirable characteristics strains. © 2021 Society of Chemical Industry.
嗜热链球菌是最重要的乳酸菌之一，广泛应用于食品发酵，有利于提高食品质量。然而，目前的遗传转化系统对嗜热链球菌 S-3 的效率不高，这阻碍了其进一步的研究。
我们为嗜热链球菌 S-3 开发了三种电穿孔转化方法，并优化了各种参数，将转化效率提高到 1.3×10 CFU/μg DNA，比未优化的提高了 32 倍。此外，转录分析表明，优化后嗜热链球菌 S-3 中的一系列感受态基因显著上调，表明转化效率的提高归因于感受态基因的表达水平。此外，为了证明它们的潜力，我们利用表达感受态基因（comEA、cbpD 和 comX）来提高转化效率。通过过表达 comEA 获得了最高的转化效率，比对照提高了 14 倍。
这是首次报道在嗜热链球菌中表达感受态基因以提高转化能力，这对开发理想特性菌株具有积极影响。© 2021 化学工业协会。
