Plasmid DNA from six strains of Rhizobium leguminosarum was separated by agarose gel electrophoresis and showed a large variation in the number and size of the plasmids. Blotting on to nitrocellulose and hybridization with a probe containing nif (nitrogen fixation) genes from Rhizobium meliloti demonstrated that all strains contain only one plasmid carrying nif genes. The molecular weights of the nif plasmids ranged between approximately 130 × 106 and 550 × 106. Using DNA-DNA hybridization no homologous sequences were detected between the nif plasmid of strain PRE and the other plasmid present in this strain. Hybridizations with RNA from bacteroids showed that only the nif plasmid is strongly expressed in the endosymbiotic state. No selective amplification of plasmid DNA occurs during the transition of free-living bacteria into bacteroids.
BanfalviZ.,
SankanyanV.,
KonczC.,
KissA.,
DushaI.,
KondorosiA.1981; Location of nodulation and nitrogen fixation genes on a high molecular weight plasmid of R. meliloti. Molecular and General Genetics 184:318–325
BisselingT.,
Van Den BosR. C.,
Van KammenA.,
Van Der PloegM.,
Van DuynP.,
HouwersA.1977; Cytofluorometrical determination of the DNAcontents of bacteroids and corresponding broth-cultured Rhizobium bacteria. Journal of General Microbiology 101:79–84
BrewinN. J.,
De JongT. M.,
PhillipsD. A.,
JohnstonA. W. B.1980a; Co-transfer of determinants for hydrogenase activity and nodulation ability in Rhizobium leguminosarum. Nature 288:77–79
BrewinN. J.,
BeringerJ. E.,
JohnstonA. W. B.1980b; Plasmid-mediated transfer of host-range specificity between two strains of Rhizobium leguminosarum. Journal of General Microbiology 120:413–420
BroughtonW. J.,
Van EgeraatA.W.S.M.,
LieT. A.1980; Dynamics of Rhizobium competition for nodulation of Pisum sativum cv. Afghanistan. Canadian Journal of Microbiology 26:562–565
CannonF. C.,
RiedelG. E.,
AusubelF. M.1979; Overlapping sequences of Klebsiella pneumoniaenif DNA cloned and characterised. Molecular and General Genetics 174:59–66
CasseF.,
BoucherC.,
JulliotJ. S.,
MichelM.,
DénariéJ.1978; Identification and characterization of large plasmids in Rhizobium meliloti using agarose gel electrophoresis. Journal of General Microbiology 113:229–242
DénariéJ.,
RosenbergC.,
BoistardP.,
TruchetG.,
Casse-DelbartF.1981; Plasmid control of symbiotic properties in Rhizobium meliloti. In: Current Perspectives in Nitrogen Fixation. Proceedings of the Fourth International Symposium on Nitrogen Fixation pp. 137–141GibsonA. H.,
NewtonW. E.
Edited by Amsterdam: Elsevier/North-Holland Biomedical Press;
GoldbachR. W.,
BorstP.,
Bollen-De BoerJ. E.,
Van BruggenE. F. J.1978; The organization of ribosomal RNA genes in the mitochondrial DNA of Tetrahymena pyriformis strain GT. Biochimica et biophysica acta 521:169–186
HombrecherG.,
BrewinN. J.,
JohnstonA. W. B.1981; Linkage of genes for nitrogenase and nodulation ability on plasmids in Rhizobium leguminosarum and R. phaseoli. Molecular and General Genetics 182:133–136
HooykaasP. J. J.,
Van BrusselA. A. N.,
Den Dulk-RasH.,
Van SlogterenG. M. G.,
SchilperoortR. A.1981; Sym plasmid of Rhizobium trifolii expressed in different rhizobial species and Agrobacterium tumefaciens. Nature; London: 291351–353
JohnstonA. W. B.,
BeynonJ. L.,
Buchanan-WollastonA. V.,
SetchellS. M.,
HirschP. R.,
BeringerJ. E.1978; High frequency transfer of nodulating ability between strains and species of Rhizobium. Nature; London: 276634–636
KrolA. J. M.,
HontelezJ. G. J.,
Van Den BosR. C.,
Van KammenA.1980; Expression of large plasmids in the endosymbiotic form of Rizobium leguminosarum. Nucleic Acids Research 8:4337–4347
NutiM. P.,
LedeboerA. M.,
LepidiA. A.,
SchilperoortR. A.1977; Large plasmids in different Rhizobium species. Journal of General Microbiology 100:241–248
NutiM. P.,
LepidiA. A.,
PrakashR. K.,
SchilperoortR. A.,
CannonF. C.1979; Evidence for nitrogen fixation (nif) genes on indigenous Rhizobium plasmids. Nature; London: 282533–535
ReyndersL.,
VisserL.,
AalbersA. M. J.,
Van KammenA.,
HouwersA.1975; A comparison of DNA from free living andendosymbiotic Rhizobium leguminosarum (strain PRE). Biochimica et biophysica acta 414:206–216
RigbyP. W. J.,
DieckmanM.,
RhodesC.,
BergP.1977; Labeling deoxyribonucleic acid to a high specific activity in vitro by nick translation with DNA polymerase I. Journal of Molecular Biology 113:237–251
RosenbergC.,
BoistardP.,
DénariéJ.,
Casse-DelbartF.1981; Genes controlling early and late functions in symbiosis are located on a megaplasmid in Rhizobium meliloti. Molecular and General Genetics 184:326–333
RuvkunG. B.,
AusubelF. M.1980; Interspecies homology of nitrogenase genes. Proceedings of the National Academy of Sciences of the United States of America 77:191–195
TichyH. V.,
LotzW.1981; Identification and characterization of large plasmids in newly isolated strains of Rhizobium leguminosarum. FEMS Microbiology Letters 10:203–207
WahlG. M.,
SternM.,
SarkG. R.1979; Efficient transfer of large DNA fragments from agarose gels to diazobenzyloxymethyl-paper and rapid hybridization by using dextran sulfate. Proceedings of the National Academy of Sciences of the United States of America 76:3683–3687
WieslanderL.1979; A simple method to recover intact high molecular weight RNA and DNA after electrophoretic separation in low gelling temperature agarose gels. Analytical Biochemistry 98:304–309