Table 1.

Bacterial strains and plasmids used in this study.

Strains or plasmids	Characteristicsa	Source
Strains
E. coli DH5α	fhuA2 Δ(argF-lacZ)U169 phoA glnV44 Φ80 Δ(lacZ)M15 gyrA96 recA1 relA1	Invitrogen
E. coli VE7108	Kmr, host of pNZ8048 and pINTZrec	Mora et al. (2004)
L. gasseri Kx110A1	Isolated from human gastric	de Klerk et al. (2016)
L. gasseri Kx110A1 ΔsrtA	L. gasseri Kx110A1 srtA deletion mutant	This study
L. gasseri Kx110A1 ΔsrtA/srtA	L. gasseri Kx110A1 srtA deletion mutant harboring pNZ8048-comSrtA	This study
Plasmids
pUC18	Ampr, E. coli cloning vector	Thermo Scientific
pUC18-∆srtA	Ampr, pUC18 derivative containing upstream and downstream DNA of L. gasseri Kx110A1 srtA gene	This study
pINTZrec	Cmr, IPSD plasmid used to assist bacterial recombineering	Zuo et al. (2019)
pINTZrec-∆srtA	Cmr, pINTZrec derivative containing upstream and downstream DNA of L. gasseri Kx110A1 srtA gene	This study
pNZ8048	Cmr, SH71 replicon plasmid	De Ruyter et al. (1996)
pNZ8048-comSrtA	Cmr, pNZ8048 derivative containing native srtA expression cassette	This study

^aKm^r, kanamycin resistant; Cm^r, chloramphenicol resistant; Amp^r, ampicillin resistant.