TABLE 1.

Strains and plasmids used in this study

Strain or plasmidDescriptionReference or source
Sinorhizobium meliloti
    Rm1021Wild-type strain; Smr43
    Rm2011Wild-type strain13
    CBT208Rm1021 rpoE2::hphThis work
    2011mTn5STM.3.12.B10Rm2011 rpoE2::mTn5A. Becker (53)
Escherichia coli
    DH5αsupE44 ΔlacU169 (φ80 lacΖΔΜ15) hsdR17 recA1 endA1 gyrA96 thi-1 relA158
Plasmids
    pRK2013Helper plasmid for triparental matings22
    pGEM-TCloning vector; AmprPromega
    pLS2.7pGEM-T smc01505Δ smc01506This work
    pLS3.4pGEM-T ′smc01504 smc01505Δ smc01506This work
    pBBR1MCS-5Cloning vector; Gmr derivative of pBBR138
    pCBT105pBBR1MCS-5 smc01505 smc01506This work
    pCBT109pBBR1MCS-5 smc01505This work
    pLS4.1pBBR1MCS-5 smc01505Δ smc01506This work
    pJQ200mp19Gene replacement vector; GmR54
    pLS5.1pJQ200mp19 ′smc01504 smc01505Δ smc01506This work
    pCBT104pJQ200mp19 smc01505 smc01506This work
    pCBT113pJQ200mp19 smc01505 smc01506::hphThis work
    pCZ750lacZ expression probe vector; Tetr8
    pLS6.20pCZ750 Psmc01504-lacZThis work
    pLS6.32pCZ750 Psmc01505-lacZThis work
    pVO205Plasmid carrying the hph gene, conferring resistance to hygromycin5