TABLE 1.

Strains, plasmids, and bacteriophages used in this study

Strain, plasmid, or phage	Relevant genotype and/or characteristic(s)	Source or reference
Strains
L. cremoris
MG1363	Plasmid-free strain	43
NZ9000	MG1363 pepN::nisRK	44
VES7552	NZ9000 Δpbp2b, NZ9000 derivative carrying deletion of pbp2b	This study
VES5748	MG1363 wpsH, spontaneous MG1363 derivative, C-to-T transition in wpsH (llmg_0226) gene	10
VES7482	Spontaneous VES5748 derivative, G1355-to-T transversion in pbp2b (llmg_0358), corresponding to W452L mutation in PBP2b	This study
VES7483	Spontaneous VES5748 derivative, G881-to-T transversion in pbp2b, corresponding to G292V mutation in PBP2b	This study
VES7484	wpsH pbp2b-1, spontaneous VES5748 derivative, C1232-to-T transition in pbp2b, corresponding to T411M mutation in PBP2b	This study
VES7485	wpsH pbp2b-2, spontaneous VES5748 derivative, G1624-to-T transversion in pbp2b, corresponding to V542F mutation in PBP2b	This study
VES7554	wpsH Δpbp2b, VES5748 derivative carrying a deletion of pbp2b	This study
NZ9000 wpsA	NZ9000 with an in-frame stop codon inserted in wpsA (llnz_0135)	17
VES7806	wpsA pbp2b-1, spontaneous NZ9000 wpsA derivative, deletion of A in position 430 in pbp2b (llnz_01875)	This study
VES7807	Spontaneous NZ9000 wpsA derivative, deletion of C in position 1727 in pbp2b	This study
VES7808	wpsH pbp2b-2, spontaneous NZ9000 wpsA derivative, deletion of 33 nucleotides from position 1335 to 1367 in pbp2b	This study
E. coli
JIM4646	TG1 strain with a chromosomal copy of repA gene, allowing replication of L. lactis pGhost9 plasmid	P. Renault, INRAE, France
Plasmids
pGhost9	Thermosensitive plasmid for gene replacement by double-crossover integration; Eryr	45
pGhost9-Δpbp2b	pbp2b integration vector for construction of pbp2b deletion mutants	This study
Bacteriophages
sk1	Skunavirus, propagated on NZ9000	46
p2	Skunavirus, propagated on NZ9000	47
MCC1	Skunavirus, derivative of sk1, propagated on NZ9000	17
MCC17	Skunavirus, derivative of sk1, propagated on NZ9000	17