TABLE 1.
Bacterial strains and plasmids used in this work
| Strain or plasmid | Relevant characteristic(s) | Source or reference |
|---|---|---|
| R. etli | ||
| CFN42 | Wild-type strain, Smr Nalr | 5 |
| DEM153 | CFN42 with a nifHa-lacZ reporter fusion in pSym, Kmr | 35 |
| DEM233 | CFN42 with a nifHc-lacZ reporter fusion in pSym, Kmr | 35 |
| SAM100 | CFN42 derivative, phaC Kmr | 8 |
| HP55 | CFN42 containing pHP55 plasmid, Tcr | This work |
| HP310 | CFN42 derivative containing chimeric operon pr c nifHcDK in pSym | This work |
| HP210 | CFN42 derivative containing pHP210 plasmid (pTR101, nifHc with its own regulatory region), Tcr | This work |
| HP220 | CFN42 derivative containing pHP220 plasmid (pTR101, nifHDKb with its own regulatory region), Tcr | This work |
| HP310 lac | HP310 derivative containing a nifH-lacZ fusion in the chimeric operon pr c nifHcDK in pSym, Kmr | This work |
| E. coli HB101 | F−hsd S20-recA 13 | 4 |
| Plasmids | ||
| pAM341 | pTR101, with a fragment containing the nifHc promoter region cloned into the XbaI site, Tcr | 24 |
| pRK2013 | Helper plasmid, ColE1, mob+ Tra+ Kmr | 11 |
| pCQ12 | pBR328, with a 4.5-kb EcoRI fragment containing the R. etli nifHDKb operon, Tcr | 26 |
| pCQ23 | pBR328, with a 4.2-kb EcoRI fragment containing the R. etli nifHc gene, Tcr | 26 |
| pTR101 | pTR100 (mini-RK2), with a 0.8-kb stability locus, Tcr | 36 |
| pIC20H | Cloning vector, Ampr | 22 |
| pKOK6 | pSUP202, with a lacZ-kan cassette | 20 |
| pWS233 | Mobilizable replicon ColE1, Gmr TcrsacRB | 30 |
| pHP40 | pCQ12, pr c nifHcDK construction in a 4.5-kb EcoRI fragment | This work |
| pHP50 | pIC20H, with a 4.5-kb EcoRI fragment containing the pr c nifHcDK construct | This work |
| pHP55 | pTR101, containing the pr c nifHcDK construct in a 4.5-kb fragment cloned on an XbaI site | This work |
| pHP100 | pWS233, with a 4.5-kb EcoRI fragment containing the pr c nifHcDK construct cloned into the EcoRI site | This work |
| pHP789 | pHP100, with a 1.6-kb PstI-EcoRI fragment from pCQ23, cloned downstream of the pr c nifHcDK construct | This work |
| pHP210 | pTR101, with a 4.5-kb EcoRI fragment containing the nifHc gene with its own regulatory region | This work |
| pHP220 | pTR101, with a 5-kb EcoRI fragment containing nifHDKb operon with its own regulatory region | This work |