Table 1. Bacterial strains, plasmids and primers used in this study.

Strains/plasmid	Relevant characteristics		References/sources
S. mutans UA159	Wild-type		Ajdic et al. (2002)
S. mutans TW296	ΔSMU864, Kanr		This study
S. mutans TW296C	TW296/pDL278:pdxR, Kanr and Spcr		This study
S. mutans TW372	ΔpdxK, Kanr		This study
S. mutans TW373	ΔpdxU, Spcr		This study
S. mutans TW374	ΔpdxKU, Spcr		This study
E. coli BL2			New England Biolabs
pDL278	Shuttle vector, Spcr		LeBanc & Lee (1991)
pMALc2x	Expression vector		New England Biolabs
Primers	Sequence (5′–3′)	Sequence (5′–3′)	Application
pdxR 5F	55-atccaagtatcattcaaacgattc	53-agaaaactggcagaattcgctaac	5′, pdxR for mutation
pdxR 3F	35-tgcagtggaattcttggctcagttg	33-tcaagtaaatgcggttcataacaaagac	3′, pdxR for mutation
pdxR C	C5-actagactgaggatccttctc	C3-agtaagattgaattctcaccaaagagc	For complementation
pdxR E	E5: ggacggatccgttagtaaatatcatgaa	E3: tcaccaaagagctctagtacttttaag	For SMU.953 expression
16S-1 rRNA	Fw: cacaccgcccgtcacacc	Rv: cagccgcaccttccgatacg	16S rRNA qPCR, 160 bp
pdxR	Fw: cagccaacaagccctttacatcc	Rv: caaggtgttcatgcgatggtagg	pdxR qPCR, 100 bp
gtfB	Fw: agcaatgcagccatctacaaat	Rv: acgaactttgccgttattgtca	gtfB qPCR, 98 bp
gtfC	Fw: atggcgacaatatgatta	Rv: cggatgaaggaataagaa	gtfC qPCR, 172 bp
gtfD	Fw: tgacttctgttcgttatg	Rv: ggttattgctggtaatga	gtfD qPCR, 98 bp
SMU860	Fw: attatccgtgaagaacta	Rv: tgattatagacagcaact	SMU860 qPCR, 143 bp
SMU861	Fw: acaatgcttctattcttctt	Rv: cctaacagcgtattgataa	SMU861 qPCR, 124 bp
SMU862	Fw: ttgttgtagtctggttgt	Rv: atagcataatcgtaatgtaagg	SMU862 qPCR, 135 bp
SMU863	Fw: atagaagaagtggctgaa	Rv: tatctgttatatcggcaatc	SMU863 qPCR, 118 bp
pdxK	Fw: ttgaagcagataagattggtt	Rv: taagcggaagacaggatt	pdxK qPCR, 133 bp
pdxU	Fw: ttagaatcactgcttgtt	Rv: attgagaataatcttcgttac	pdxU qPCR, 126 bp
SMU867	Fw: cggctatgatgataacag	Rv: ttgaaggagaagagtgat	SMU867 qPCR, 118 bp

Kan^r and Spc^r, for kanamycin and spectinomycin resistance, respectively. Sequences underlined are restriction sites engineered for cloning.