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

Bacteria/plasmid	Relevant feature	Reference
E. coli DH5α/λpir	Strain for propagating R6K suicide plasmids	Lab collection
E. coli S17-1/λpir	IncP conjugal donor	Kalogeraki & Winans (1997)
E. coli XL-1 Blue	Standard alpha-complementation strain	Lab collection
E. coli MC4100	K-12 derivative, ΔlacZ	Lab collection
A. tumefaciens NTL4	Ti plasmid-less derivative, nopaline chromosomal background	Zhu et al. (1998)
KLH11	WT	Mohamed et al. (2008)
KLH11-EC1	RifR	Zan et al. (2012)
KLH11-SK01	ΔssaI, RifR	Zan et al. (2012)
KLH11-SK02	ΔssaI ΔssbI, RifR	Zan et al. (2012)
KLH11-OKC2	sscI-lacZ, RifR KmR	This study
KLH11-OKC6	ΔssaI ΔssbI ssc-lacZ, RifR KmR	This study
CGA814	Rh. palustris; rpaI-lacZ, KmR	Schaefer et al. (2008)
pCR2.1-TOPO	PCR fragment cloning vector, Ap/KmR	Invitrogen
pBBR1-MCS5	BHR Plac expression vector, GmR	Kovach et al. (1995)
pSRKTc	BHR expression vector containing lac promoter and lacIq, TcR	Khan et al. (2008)
pVIK112	R6K-based lacZ transcriptional fusion, KmR	Kalogeraki & Winans (1997)
pRA301	BHR lacZ translational fusion vector	Akakura & Winans (2002)
pEC108	pBBR1-MCS5 derivative carrying full-length Plac-ssaI, GmR	Zan et al. (2012)
pEC109	pBBR1-MCS5 derivation carrying full-length Plac-ssbI, from pEC110, GmR	Zan et al. (2012)
pEC112	pBBR1-MCS5 derivative, carrying full-length Plac-ssaR, from pEC106, GmR	Zan et al. (2012)
pEC116	pRA301 derivation, PssaI-lacZ, SpR	Zan et al. (2012)
pEC121	pRA301 derivative, PssbI-lacZ, Sp/SmR	Zan et al. (2012)
pOKC1	pCR2.1-TOPO, carrying internal fragment of sscI, KmR	This study
pOKC2	pVIK112 derivative, carrying internal fragment of sscI, KmR	This study
pOKC3	pCR2.1-TOPO, carrying full-length sscI, KmR	This study
pOKC4	pSRKTC derivative, carrying full-length Plac-sscI, TcR	This study
pOKC8	pRA301 derivation, PsscI-lacZ, SpR	This study

Sm, Streptomycin; Tc, tetracycline.