Table 1.
Bacterial strains and plasmids used
| Bacterial strains/plasmids | Relevant characteristics | Source/references |
|---|---|---|
| Strains | ||
| Rhizobium etli | ||
| CFN42 | Streptomycin resistant, nodulates Phaseolus vulgaris | (17) |
| Escherichia coli | ||
| DH5α | Host strain for plasmids | (47) |
| BW21038 | gusA derivarive | (48) |
| DH10B | lacZ derivative | GibcoBRL |
| BL21(DE3) | Host strain used for expression of target proteins | (22) |
| Plasmids | ||
| pBBR1MCS-5 | Gentamycin resistant, cloning vector replicable in R.etli | (49) |
| pBBMCS53 | pBBR1MCS-5 derivative carrying a promoter minus β-glucuronidase gene (gusA) | (20) |
| pRK415 | Tetracycline resistant, derivative of pRK290 | (50) |
| pLysS | Chloramphenicol resistant, production of lysozyme for repression of T7 polymerase | (22) |
| pET-28a(+) | Kanamycin resistant, expression vector | Novagen |
| pRKS70 | pRK415 derivative carrying a 1726 bp fragment containing the sigA gene of the CFN42 strain | This work |
| pGUSphemC | pBBMCS53 derivative carrying a 278 bp fragment containing the native promoter of hemC gene. The fragment was generated by PCR and carries 57 bp upstream of gene and 221 bp of hemC | This work |
| pGUSphemC-10 | A pGUSphemC derivative in which the promoter element −10 was changed from [TACGAG] to [GCGGAG] | This work |
| pGUSphemC-35 | A pGUSphemC derivative in which the promoter element −35 was changed from [ATTGCG] to [AAGACG] | This work |
| pGUSphemC-1035 | A pGUSphemC derivative, but with mutated −10 and −35 elements from the promoter. Both elements were changed to the sequences indicated before | This work |