Table 1.

Current tools available for lactic acid bacteria genome editing

Tools	Examples of partial applications	Characteristics	References
Plasmids-based allelic exchange	Lc. lactis, S. thermophilus, E. faecalis	Homologous recombination-dependent; marker free; time-consuming	[19, 20]
DsDNA recombineering	Lb. plantarum, Lb. casei	Recombinase-mediated; high efficiencies for both deletion and insertion; marker-dependent	[29, 30]
SsDNA recombineering	Lb. reuteri, Lc. lactis, Lb. plantarum, Lb. gasseri	Mutation efficiency 0.4–19%; applicable to genomic mutagenesis; marker free	[31]
CRISPR–Cas-assisted recombineering	Lb. reuteri, Lc. Lactis	High efficiency (up to 100%) for small deletions (< 1.0 kb in Lb. reuteri, < 100 bp in Lc. lactis); marker free	[35, 36]
CRISPR–Cas9D10A	Lb. casei	Used for both gene deletion and insertion (25–65%); simplified editing procedure; marker free	[39]
CRISPRi	Lb. plantarum, Lc. lactis	Used to repress multiple target genes simultaneously; reversible effects; precise targeting; marker free	[40–43]