Table 1 Bacterial strains and plasmids.

Bacteria

S. meliloti

   1021

Wild-type SU47 derivative, Sm^r

[75]

   2011

Wild-type SU47 derivative, Sm^r

[76]

   1021Δhfq

1021 hfq mutant strain, Sm^r

This work

   2011-1.2

2011 hfq insertion derivative (control str.), Sm^r, Km^r

This work

   2011-3.4

2011 hfq insertion mutant, Sm^r, Km^r

This work

   1021hfq^FLAG

1021 derivative expressing a 3 × Flag-tagged Hfq, Sm^r

This work

E. coli

   DH5α

F^- endA1, glnV44, thi-1, recA1, relA1, gyrA96, deoR, nupG, φ80d, lacZ ΔM15 Δ(lacZYA-argF)U169, hsdR17(r_K^- m_K⁺), λ-

Bethesda Research Lab.

Plasmids

   pRK2013

Helper plasmid, Col E1, Km^r

[77]

   pGEM^®-T Easy

Cloning vector for PCR, Ap^r

Promega Corporation

   pK18mobsacB

Suicide vector in S. meliloti Km^r, sacB, ori V

[78]

   pJB3Tc19

Broad host-range IncP cloning vector, Ap^r, Tc^r

[79]

   pBluescriptII KS+

Multicopy cloning vector, Ap^r

Stratagene

   pGEMhfq

1,684-bp of hfq genomic region in pGEM-T

This work

   pK18_1.2

Internal fragment of hfq ORF in pK18mobsacB

This work

   pK18_3.4

Internal fragment of hfq ORF in pK18mobsacB

This work

   pGEMΔhfq

Genomic region with deletion of hfq in pGEM-T

This work

   pK18Δhfq

Genomic region with deletion of hfq in pK18

This work

   pGEMHfq

pGEM-T containing hfq promoter and ORF

This work

   pJBHfq

pJB3Tc20 containing hfq promoter and ORF

This work

   pKS3 × Flag

3 × FLAG encoding fragment in pBluescriptII KS+

This work

   pKS3 × Flag5

pKS3 × Flag with upstream region of hfq

This work

   pKSHfq3 × Flag

pBluescriptII KS+ with Flag-tagged hfq ORF

This work

   pGEMHfq3 × Flag

pGEM-T with Flag-tagged hfq ORF

This work

   pK18Hfq3 × Flag

pK18mobsacB with Flag-tagged hfq ORF

This work