Polyphasic Taxonomy of Rhizobia: Emendation of the Genus Sinorhizobium and Description of Sinorhizobium meliloti comb, nov., Sinorhizobium saheli sp. nov., and Sinorhizobium teranga sp. nov.
A total of 80 bacterial strains isolated from different Sesbania and Acacia species growing in various sites in Senegal (West Africa) were compared with 35 reference strains of Rhizobium, Bradyrhizobium, Azorhizobium, and Agrobacterium species and with 33 representative strains of the different groups of Brazilian isolates described on the basis of the results of a numerical analysis of the whole-cell protein patterns obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Fifty-two strains could be placed in three protein electrophoretic clusters, two of which were different from the clusters containing various reference or representative strains, while 30 other strains could not be placed in any group. The strains belonging to the three clusters were studied by determining their nodulation host ranges and their morphological, physiological, and auxanographic characteristics. Representative strains of the three clusters were also genotypically characterized by determining their DNA base compositions, by performing DNA-DNA and DNA-rRNA hybridization experiments, and by determining their 16S rRNA gene sequences. Our results showed that two of the clusters identified on the basis of SDS-PAGE data are genotypically and phenotypically distinct groups that belong on the Rhizobium meliloti-Rhizobium fredii rRNA branch. The third cluster is localized on the Rhizobium loti rRNA branch in the vicinity of Rhizobium huakuii and contains strains isolated in Africa, in Brazil, and in New Zealand from different leguminous species. On the basis of the results of the present study, we propose to emend the genus Sinorhizobium and to reclassify R. meliloti as Sinorhizobium meliloti comb. nov. In addition, two new species, Sinorhizobium saheli and Sinorhizobium teranga, are proposed for isolates from Senegal.
Published Online:
Copyright 1994 International Union of Microbiological Societies
BrosiusJ.,
PalmerM. L.,
KennedyP. J.,
NollerH. F.1978; Complete nucleotide sequence of a 16S ribosomal RNA gene from Escherichia coli. Proc. Natl. Acad. Sci. USA 75:4801–4805
ChenW. X.,
YanG. H.,
LiJ. L.1988; Numerical taxonomic study of fast-growing soybean rhizobia and a proposal that Rhizobium fredii be assigned to Sinorhizobium gen. nov. Int. J. Syst. Bacteriol. 38:392–397
CrowV. L.,
JarvisB. D. H.,
GreenwoodR. M.1981; Deoxyribonucleic acid homologies among acid-producing strains of Rhizobium. Int. J. Syst. Bacteriol. 31:152–172
De LeyJ.1970; Reexamination of the association between melting point, buoyant density, and chemical base composition of deoxyribonucleic acid. J. Bacteriol. 101:737–754
De LeyJ.1991; The proteobacteria: ribosomal RNA cistron similarities and bacterial taxonomy. 2109–2140 In
BalowsA.,
TrüperH. G.,
DworkinM.,
HarderW.,
SchleiferK. H.
(ed.) The prokaryotes, 2nd. ed.. Springer-Verlag; New York:
De LeyJ.,
De SmedtJ.1975; Improvements of the membrane filter method for DNA:rRNA hybridization. Antonie van Leeu-wenhoek J. Microbiol. Serol. 41:287–307
De LeyJ.,
Van MuylemJ.1963; Some applications of deoxyribonucleic acid base composition in bacterial taxonomy. Antonie van Leeuwenhoek J. Microbiol. Serol. 29:344–358
DreyfusB.,
GarciaJ. L.,
GillisM.1988; Characterization of Azorhizobium caulinodans gen. nov., sp. nov., a stem-nodulating nitrogen-fixing bacterium isolated from Sesbania rostrata. Int. J. Syst. Bacteriol. 38:89–98
DreyfusB. L.,
DommerguesY.1981; Nodulation of Acacia species by fast- and slow-growing tropical strains of Rhizobium. Appl. Environ. Microbiol. 41:97–99
GrahamP. H.,
SadowskyM. J.,
KeyserH. H.,
BarnetY. M.,
BradleyR. S.,
CooperJ. E.,
De LeyJ.,
JarvisB. D. W.,
RoslyckyE. B.,
StrijdomB. W. J.,
YoungP. W.1991; Proposed minimal standards for the description of new genera and species of root-and stem-nodulating bacteria. Int. J. Syst. Bacteriol. 41:582–587
JarvisB. D. W.,
DownerH. L. J.,
YoungP. W.1992; Phylogeny of fast-growing soybean-nodulating rhizobia supports synonymy of Sinorhizobium and Rhizobium and assignment to Rhizobium fredii. Int. J. Syst. Bacteriol. 42:93–96
JarvisB. D. W.,
GillisM.,
De LeyJ.1986; Intra- and intergeneric similarities between the ribosomal ribonucleic acid cistrons of Rhizobium and Bradyrhizobium species and some related bacteria. Int. J. Syst. Bacteriol. 36:129–138
JordanD. C.1984; Rhizobiaceae Conn 1938, 321AL. 234–256 In
KriegN. R.,
HoltJ. G.
(ed.) Bergey’s manual of systematic bacteriology vol. 1 The Williams & Wilkins Co.; Baltimore:
KerstersK.,
De LeyJ.1984; Genus III. Agrobacterium Conn 1942. 244–254 In
KriegN. R.,
HoltJ. G.
(ed.) Bergey’s manual of systematic bacteriology vol. 1 The Williams & Wilkins Co.; Baltimore:
KerstersK.,
HinzK. H.,
HertleA.,
SegersP.,
LievensA.,
SiegmannO.,
De LeyJ.1984; Bordetella avium sp. nov., isolated from the respiratory tracts of turkeys and other birds. Int. J. Syst. Bacteriol. 34:56–70
KiredjianM.,
HolmesB.,
KerstersK.,
GuilvoutJ.,
De LeyJ.1986; Alcaligenes piechaudii, a new species from human clinical specimens and the environment. Int. J. Syst. Bacteriol. 36:282–287
MarmurJ.,
DotyP.1962; Determination of the base composition of deoxyribonucleic acid from its thermal denaturation temperature. J. Mol. Biol. 5:109–118
Martinez-RomeroE.,
SegoviaL.,
MercanteF. M.,
FrancoA. A.,
GrahamP.,
PardoM. A.1991; Rhizobium tropici, a novel species nodulating Phaseolus vulgaris L. beans and Leucaena sp. trees. Int. J. Syst. Bacteriol. 41:417–426
MoreiraF.,
GillisM.,
PotB.,
KerstersK.,
FrancoA. A.1993; Characterization of rhizobia isolated from different divergence groups of tropical Leguminosae by comparative Polyacrylamide gel electrophoresis of their total proteins. Syst. Appl. Microbiol. 16:135–146
PotB.,
GillisM.,
HosteB.,
Van De VeldeA.,
BekaertF.,
KerstersK.,
De LeyJ.1989; Intra- and intergeneric relationships of the genus Oceanospirillum. Int. J. Syst. Bacteriol. 39:23–34
PotB.,
VandammeP.,
KerstersK.1994; Analysis of electrophoretic whole organism protein fingerprints. 493–521 In
GoodfellowM.,
O’DonnellT.
(ed.) Chemical methods in prokaryotic systematics John Wiley & Sons; Chichester, United Kingdom:
RinaudoG.,
FernandezM. P.,
EffosseA.,
PicardB.,
BardinR.1993; Enzyme polymorphism of Azorhizobium strains and other stem and root-nodulating bacteria isolated from Sesbania rostrata. Res. Microbiol. 154:55–67
RinaudoG.,
OrengaS.,
FernandezM.,
MeugnierH.,
BardinR.1991; DNA homologies among members of the genus Azorhizobium and other stem- and root-nodulating bacteria isolated from the tropical legume Sesbania rostrata. Int. J. Syst. Bacteriol. 41:114–120
SawadaH.,
IekiH.,
OyaizuH.,
MatsumotoS.1993; Proposal for rejection of Agrobacterium tumefaciens and revised descriptions for the genus Agrobacterium and for Agrobacterium radiobacter and Agrobacterium rhizogenes. Int. J. Syst. Bacteriol. 43:694–702
ScholiaM. H.,
ElkanG. H.1984; Rhizobium fredii sp. nov., a fast-growing species that effectively nodulates soybeans. Int. J. Syst. Bacteriol. 34:484–486
SegoviaL.,
YoungJ. P. W.,
Martinez-RomeroE.1993; Reclassification of American Rhizobium leguminosarum biovar phaseoli type I strains as Rhizobium etli sp. nov. Int. J. Syst. Bacteriol. 43:374–377
VauterinL.,
VauterinP.1992; Computer-aided objective comparison of electrophoresis patterns for grouping and identification of microorganisms. Eur. Microbiol. 1:37–41
VincentJ. M.1970; A manual for the practical study of root-nodule bacteria. International Biological Programme Handbook no. 1573–97 Blackwell Scientific Publications, Ltd.; Oxford:
WillemsA.,
CollinsM. D.1992; Evidence for a close genealogical relationship between Afipia, the causal organism of cat scratch disease, Bradyrhizobium japonicum and Blastobacter denitrificans. FEMS Microbiol. Lett. 96:241–246
WillemsA.,
CollinsM. D.1993; Phylogenetic analysis of rhizobia and agrobacteria based on 16S ribosomal DNA sequences. Int. J. Syst. Bacteriol. 43:305–313
YanagiM.,
YamasotoK.1993; Phylogenetic analysis of the family Rhizobiaceae and related bacteria by sequencing of 16S rRNA gene using PCR and DNA sequencer. FEMS Microbiol. Lett. 107:115–120
YoungJ. P. W.1991; Phylogenetic classification of nitrogen-fixing organisms. 43–86 In
StaceyG.,
BurrisR. H.,
EvansH. J.
(ed.) Biological nitrogen fixation Chapman & Hall; New York:
YoungJ. P. W.,
DownerH. L.,
EardlyB. D.1991; Phylogeny of the phototrophic Rhizobium strain BTAil by polymerase chain reaction-based sequencing of a 16S rRNA gene segment. J. Bacteriol. 173:2271–2277
ZhangX.,
HarperR.,
KarsistoM.,
LindströmK.1991; Diversity of Rhizobium bacteria isolated from root nodules of leguminous trees. Int. J. Syst. Bacteriol. 41:104–113
Polyphasic Taxonomy of Rhizobia: Emendation of the Genus Sinorhizobium and Description of Sinorhizobium meliloti comb, nov., Sinorhizobium saheli sp. nov., and Sinorhizobium teranga sp. nov.