TABLE 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Relevant characteristics | Reference or source |
|---|---|---|
| E. coli strains | ||
| HB101 | pro leu thi gal lacY recA str hsdD hsdM | 5 |
| S17-1 | RK2 tra regulon | 42 |
| R. leguminosarum bv. trifolii strains | ||
| NZP561 | Also known as CC275e; commercial inoculant strain; wild type | Our laboratory |
| HM1 | NZP561 otsA::EZTn5 (Neor) | This study |
| HM2 | NZP561 treY::EZTn5 (Neor) | This study |
| HM3 | NZP561 otsA::lacZ, pFUS2 IDM (Gmr) | This study |
| HM4 | NZP561 treY::lacZ, pFUS2 IDM (Gmr) | This study |
| HM5 | HM1 treY::lacZ, pFUS2 IDM (Neor Gmr) | This study |
| HM12 | NZP561 treY::lacZ, pFUS2 CMD (Gmr) | This study |
| TH1 | HM2 otsA::lacZ, pFUS2 IDM (Neor Gmr) | This study |
| TH3 | NZP561 otsA::lacZ, pFUS2 CMD (Gmr) | This study |
| Plasmids | ||
| pLAFR1 | Broad-host-range cosmid; Tcr | 17 |
| pFUS2 | oriVColE1oriTRK2lacZ transcriptional reporter; suicide vector, Gmr | 2 |
| pPH1J1 | Conjugative plasmid, IncP Gmr | 23 |
| pUC8 | Cloning vector, oriColE1lacZα Apr | 54 |
| pHM2 | pLAFR1 cosmid containing NZP561 DNA that hybridized to otsA probe | This study |
| pHM3 | pLAFR1 cosmid containing NZP561 DNA that hybridized to treY probe | This study |
| pHM4 | pUC8 containing 6.0-kb EcoRI fragment of pHM2 that contains the entire otsA gene | This study |
| pHM5 | pLAFR1 containing otsA::EZTn5 EcoRI fragment | This study |
| pHM6 | pHM3 treY::EZTn5 | This study |