CRISPR-Cas (Clustered regularly interspaced short palindromic repeats-CRISPR associated proteins) systems are widely distributed in lactic acid bacteria (LAB), contributing to their RNA-mediated adaptive defense immunity. The CRISPR-Cas-based genetic tools have exhibited powerful capability. It has been highly utilized in different organisms, accelerating the development of life science. The review summarized the components, adaptive immunity mechanisms, and classification of CRISPR-Cas systems; analyzed the distribution and characteristics of CRISPR-Cas system in LAB. The review focuses on the development of CRISPR-Cas-based genetic tools in LAB for providing latest development and future trend. The diverse and broad applications of CRISPR-Cas systems in food/probiotic industry are introduced. LAB harbor a plenty of CRISPR-Cas systems, which contribute to generate safer and more robust strains with increased resistance against bacteriophage and prevent the dissemination of plasmids carrying antibiotic-resistance markers. Furthermore, the CRISPR-Cas system from LAB could be used to exploit novel, flexible, programmable genome editing tools of native host and other organisms, resolving the limitation of genetic operation of some LAB species, increasing the important biological functions of probiotics, improving the adaptation of probiotics in complex environments, and inhibiting the growth of foodborne pathogens. The development of the genetic tools based on CRISPR-Cas system in LAB, especially the endogenous CRISPR-Cas system, will open new avenues for precise regulation, rational design, and flexible application of LAB.

中文翻译：

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乳酸菌CRISPR-Cas系统及其在食品科学中的应用

CRISPR-Cas（成簇规则间隔短回文重复序列-CRISPR相关蛋白）系统广泛分布于乳酸菌（LAB）中，有助于其RNA介导的适应性防御免疫。基于CRISPR-Cas的遗传工具展现出了强大的能力。它在不同的生物体中得到了高度利用，加速了生命科学的发展。综述总结了CRISPR-Cas系统的组成、适应性免疫机制和分类；分析了实验室中CRISPR-Cas系统的分布和特点。该综述重点关注实验室中基于 CRISPR-Cas 的遗传工具的开发，以提供最新进展和未来趋势。介绍了CRISPR-Cas系统在食品/益生菌行业中多样化和广泛的应用。LAB 拥有大量 CRISPR-Cas 系统，有助于产生更安全、更强大的菌株，增强对噬菌体的抵抗力，并防止携带抗生素抗性标记的质粒传播。此外，LAB的CRISPR-Cas系统可用于开发本地宿主和其他生物体的新颖、灵活、可编程的基因组编辑工具，解决一些LAB物种的遗传操作限制，增加益生菌的重要生物学功能，提高益生菌的生物活性。益生菌适应复杂环境，抑制食源性病原体的生长。基于CRISPR-Cas系统的LAB遗传工具，特别是内源性CRISPR-Cas系统的开发，将为LAB的精准调控、合理设计和灵活应用开辟新途径。