Abstract:With a variety of probiotic properties such as lowering cholesterol, maintaining flora balance and enhancing immunity, lactic acid bacteria (LAB) is an important microorganism in the food industry. Strain development is frequently used to improve the performance and functionality of industrially important microbes. A brief overview of the characteristics and applications of three improved techniques of LAB, including traditional improvement, transposon mutagenesis and CRISPR was summaried. Traditional techniques for LAB improvement include adaptive evolution, random mutagenesis and protoplast fusion, which can improve LAB but are complex and ineffective. Transposon mutagenesis, a technique based on the inactivation of genes by blocking transcriptional or translational processes, is often used in the construction of LAB mutant libraries, which is efficient and simple, but is dependent on DNA strand breaks, with a low safety profile and being not applicable to a wide range of host characteristics. CRISPR editing technology is widely used in LAB, which enables simultaneous editing of multiple loci and is a powerful tool for gene silencing and transcriptional regulation, but the technique relies on DNA strand breaks and homologous recombination and has a high off-target rate. In addition, the construction and perspective of currently emerging CRISPR-associated transposon (CAST) editing systems are also discussed. The CAST enables efficient, accuracy, marker-free insertion of large fragments (>10kbp) of donor DNA without relying on double strand break and homologous recombination, having an extremely low off-target rate, showing great advantages in high accuracy targeting and efficient integration techniques, providing a reference in high accuracy and efficient LAB gene editing in future. This review could provide relevant theoretical guidance for the subsequent genetic improvement and function analysis of LAB gene.