TABLE 1.

Strains, plasmids, and primers

Strain, plasmid, or primerRelevant genotypic or phenotypic characteristic(s)aReference and/or origin or source
R. palustris strains
    CGA009Wild-type strain; spontaneous Cmr derivative of CGA00116
    CGA570Spontaneous mutant able to grow with cyclohexanecarboxylate in the presence of ammonium sulfate (NifA, S213P)CGA009; this study
    CGA571Spontaneous mutant able to grow with cyclohexanecarboxylate in the presence of ammonium sulfate (NifA, Q209P)CGA009; this study
    CGA572Spontaneous mutant able to grow with cyclohexanecarboxylate in the presence of ammonium sulfate (NifA, L212R)CGA009; this study
    CGA574Spontaneous mutant able to grow with cyclohexanecarboxylate in the presence of ammonium sulfate (NifA, M202K)CGA009; this study
    CGA757ΔnifA (1,332 bp deleted)CGA009; this study
    CGA581Recombinant strain with mutated nifA [nifA*(Q209P)]CGA757; this study
    CGA584Recombinant strain with mutated nifA [nifA*(M202K)]CGA757; this study
E. coli strains
    DH5αF λ recA1Δ(lacZYA-argF)U169 hsdR17 thi-1 gyrA96 supE44 endA1 relA1 φ80lacZΔM15GIBCO-BRL
    S17-1thi pro hdsR hdsM+ recA; chromosomal insertion of RP4-2 (Tc::MuKm::Tn7)31
Plasmids
    pJQ200KSGmr, sacB, mobilizable suicide vector26
    pUC19Apr, high-copy-number cloning vector35
    pUC19-nifA*571Apr, 3-kb fragment containing the nifA gene and flanking regions from CGA571 amplified by PCR and cloned into XbaI sites of pUC19This study
    pJQ200KS-nifA*571Gmr, 3-kb fragment containing the nifA gene and flanking regions from CGA571 amplified by PCR and cloned into XbaI sites of pJQ200KSThis study
    pUC19-nifA*574Apr, 3-kb fragment containing the nifA mutant gene and flanking regions from CGA574 amplified by PCR and cloned into XbaI sites of pUC19This study
    pJQ200KS-nifA*574Gmr, 3-kb fragment containing the nifA mutant gene and flanking regions from CGA574 amplified by PCR and cloned into XbaI sites of pJQ200KSThis study
  • a Gmr, gentamicin resistance; Apr, ampicillin resistance; Cmr, chloramphenicol resistance.