TABLE 1.

Strains and plasmids

Strain or plasmid	Description	Reference(s) or source
Strains
S. meliloti
Rm2011	Wild type; Nxr Smr	10
Rm101	Rm2011 mucRΩ; Spcr cassette from pHP45Ω inserted into the PmacI site within mucR	6
SmSRΔG	Rm2011 ΔwggR; deletion of the wggR gene comprising 490 nucleotides of the 3′ terminus of the wggR coding region and 17 nucleotides downstream of wggR	43
SmBBΔG101	Rm2011 ΔwggR mucRΩ; double mutant	1
2011mTn5STM.2.01.B05	Rm2011 sinR::mini-Tn5	39
Rm1021	Wild type; Nxr Smr	27
Rm8530	Rm1021 expR+	18
Rm11511	Rm1021 sinI::Km	33
Rm11527	Rm8530 sinI::Km	32
Rm1021 sinR	Rm1021 sinR::mini-Tn5	This work
Rm8530 sinR	Rm8530 sinR::mini-Tn5	This work
E. coli
DH5α	F−endA1 supE44 thi-1 λ-recA1 gyrA96 relA1 deoRΔ(lacZYA-argF)U169	22
S17-1	E. coli 294 Thi RP4-2-Tc::Mu-Km::Tn7 integrated into the chromosome	44
M15pREP4	Nxs Strs Rifs Thi− Lac− Ara+ Gal+ Mtl− F− RecA+ Uvr+ Lon+	Qiagen, Hilden, Germany
Plasmids
pSRPP18	Promoter probe vector, pUC derivative; promoterless lacZ gene; integrates between the exoP terminator and the thiD gene	1
pCR-TOPO	TOPO cloning kit	Invitrogen, Karlsruhe, Germany
pJN105	araC-PBAD cassette cloned in pBBR1MCS5; Gmr	36
pJNexpR	pJN105 containing expR	3
pHU231	Tcr; pRK290 with a 388-bp HaeII insert containing pUC18 polylinker	25, 42
pLK64	pPHU231 containing sinI-EGFP translational fusion; Tcr	This work