TABLE 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Genotype or descriptiona | Source |
|---|---|---|
| Strains | ||
| Escherichia coli | ||
| DH5α | supE44 ΔlacU169 (φ80lacZΔM15) hsdR17 recA1 endA1 gyrA96 thi-1 relA1 | 23 |
| MT616 | pro thi endA hsdR supE44 recA56, pRK2013Km::Tn9 | 17 |
| Rhizobium etli | ||
| CE3 | str-1 Lpe+ Ndv+ Fix+ | 36 |
| CE367 | str-1 lpeA367::Tn5-gusA1 Ndv+ Fix+ | 40 |
| CE426 | str-1 mTn5SsgusA11 (inserted at unknown site) Lpe+ Ndv+ Fix+ | This work |
| CE430 | str-1 ΔlpeA::Km Ndv+ Fix+ | This work |
| CE431 | str-1 ORF2::Km Ndv+ Fix+ | This work |
| CE432 | str-1 Ω(pJQ200::Km::ΔlpeA insert at XbaI site of lpe3) Lpe+ Ndv+ Fix+ | This work |
| CE445 | str-1 lpeA::Km Ndv+ Fix+ | This work |
| CE462 | str-1 ORF3::Km Ndv+ Fix+ | This work |
| Plasmids | ||
| pBluescript | Cloning vector | Stratagene |
| pRK404E1 | incP, Tcr, with second EcoRI site of pRK404 (15) eliminated | G. Roberts |
| pJQ200SK− | Suicide plasmid, Gmr, sacB traJ lacZα | 37 |
| pJQ200uCi | Suicide plasmid, Gmr, sacB traJ lacZα | 37 |
| pUC4K | Contains Kmr cassette used for generation of lpe mutants | Pharmacia |
| PCAM111 | Smr Spr mTn5SsgusA11 (carried in pUT vector) | 45 |
| pSB504 | pRK600Ω::Tn5-gusA7 | 39 |
a
::Km, insertion of Kanamycin resistance cassette from pUC4K; ORF2 and ORF3 are ORFs within lpe3 not shown to be required individually for Lpe+; Ndv+ Fix+, elicits normally developed nitrogen-fixing nodules on P. vulgaris.