TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmid	Relevant phenotype or genotype	Source or reference
L. lactis IL1403	Plasmid-free laboratory strain	8
L. lactis IL1403 Nisr	Nisr	This work
L. lactis MG1363	Derivative of L. lactis NCD0712	14
L. lactis MG1363ΔdltD	Derivative of L. lactis	13
	MG1363 carrying a deletion in dltD
L. lactis MG1363ΔahrC	Derivative of L. lactis	34
	MG1363 carrying a deletion in ahrC
L. lactis NZ9000	L. lactis MG1363 pepN::nisRK	31
L. lactis NZ9000ΔgalAMK	Derivative of L. lactis NZ9000 carrying a deletion in galAMK	R. A. Neves and W. A. Pool lab collection
pNZ8048	Gene expression vector with nisin-inducible PnisA promoter, Cmr	11
pJK1	pNZ8048 derivative; yneGH controlled by PnisA	This work
pFaB	pNZ8048 derivative; ysaB controlled by PnisA	This work
pFaBC	pNZ8048 derivative; ysaBC controlled by PnisA	This work