Table 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Relevant characteristicsa | Reference or source |
|---|---|---|
| S. meliloti strains | ||
| Rm2011 | Wild type; Nalr Strr | 6 |
| Rm1021 | SU47 expR102::ISRm2011-1; Strr | 28 |
| Rm8530 | Rm1021 expR+; Strr | 14 |
| 2011m.E07 | 2011mTn5STM.1.03.E07, Rm2011 flgE::mini-Tn5; Nalr Strr Neor | 35 |
| 2011mTn5STM.4.06.G01 | Rm2011 wgeB::mini-Tn5; Nalr Strr Neor | 35 |
| Sm2B3001 | Rm2011 with a restored expR gene; Nalr Strr | 2 |
| Sm2B5005 | Sm2B3001 flgE::mini-Tn5; Nalr Strr Neor | 2 |
| Sm2B6005 | Sm2B3001 visN::Sptr; Nalr Strr Sptr | 2 |
| 2011R | Rm2011 with a restored expR gene; Nalr Strr | This study |
| 2011RFg | 2011R flgE::mini-Tn5; Nalr Strr Neor | This study |
| 2011rhbA62 | Rm2011 rhbA::Tn5lac; Strr Rifr Neor | 25 |
| QN1021 | Rm1021 with a fully deleted expR locus; Strr | This study |
| 1021F | Rm1021 flaA flaB; Strr Hygr | This study |
| 1021R | Rm1021 with a restored expR gene; Strr | This study |
| 1021rhbA | Rm1021 rhbA::Tn5lac; Strr Neor | This study |
| 1021Y | Rm1021 ΔexoY; Strr | This study |
| 1021YF | 1021Y flaA flaB; Strr Hygr | This study |
| 1021X | Rm1021 ΔexoX; Strr | This study |
| 1021XF | 1021X flaA flaB; Strr Hygr | This study |
| 1021XY | 1021X ΔexoY; Strr | This study |
| Rm11601 | Rm8530 flaA flaB; Strr Hygr | 16 |
| 8530Vis | Rm8530 with full deletion of visN visR; Strr | B. Scharf |
| 8530Fg | Rm8530 flgE::mini-Tn5; Strr Neor | This study |
| Rm9020 | Rm8530 exoY::Tn5-132; Strr Otcr | 15 |
| 11601Y | Rm11601 ΔexoY; Strr Hygr | This study |
| 8530W | Rm8530 wgeB::mini-Tn5; Strr Neor | This study |
| 11601W | Rm11601 wgeB::mini-Tn5; Strr Neor | This study |
| E. coli strains | ||
| DH5α | supE44 ΔlacU169 ϕ80d lacZΔM15 recA1endA1gyrA96thi-1relA1hsdR171 | Bethesda Research Lab |
| S17-1 | thiprorecAhsdRhsdM; Rp4Tc::Mu, Km::Tn7; Tmpr Strr Sptr | 41 |
| Plasmids | ||
| pCR-XL-TOPO | Cloning vector; Kanr | Invitrogen |
| pK18mobsacB | Suicide plasmid; Kanr | 39 |
| pK18-ΔexpR | pK18mobsacB carrying the deleted version of the expR locus; Kanr | This study |
| pK18-expR | pK18mobsacB carrying the expR gene from Rm8530; Kanr | This study |
| pK18-ΔexoY | pK18mobsacB carrying the deleted version of the exoY locus; Kanr | This study |
| pK18-ΔexoX | pK18mobsacB carrying the deleted version of the exoX locus; Kanr | This study |
a
Nalr, Strr, Neor, Sptr, Rifr, Hygr, Otcr, Tmpr, and Kanr indicate nalidixic acid, streptomycin, neomycin, spectinomycin, rifampin, hygromycin, oxytetracycline, trimethoprim, and kanamycin resistance, respectively.