Affiliation:
1. Laboratorio de Microbiología, E.T.S. Ingenieros Agrónomos, Universidad Politécnica de Madrid
2. Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Universitaria s/n, 28040 Madrid, Spain
Abstract
ABSTRACT
Uptake hydrogenases allow rhizobia to recycle the hydrogen generated in the nitrogen fixation process within the legume nodule. Hydrogenase (
hup
) systems in
Bradyrhizobium japonicum
and
Rhizobium leguminosarum
bv. viciae show highly conserved sequence and gene organization, but important differences exist in regulation and in the presence of specific genes. We have undertaken the characterization of
hup
gene clusters from
Bradyrhizobium
sp. (
Lupinus
),
Bradyrhizobium
sp. (
Vigna
), and
Rhizobium tropici
and
Azorhizobium caulinodans
strains with the aim of defining the extent of diversity in
hup
gene composition and regulation in endosymbiotic bacteria. Genomic DNA hybridizations using
hupS
,
hupE
,
hupUV
,
hypB
, and
hoxA
probes showed a diversity of intraspecific
hup
profiles within
Bradyrhizobium
sp. (
Lupinus
) and
Bradyrhizobium
sp. (
Vigna
) strains and homogeneous intraspecific patterns within
R. tropici
and
A. caulinodans
strains. The analysis also revealed differences regarding the possession of hydrogenase regulatory genes. Phylogenetic analyses using partial sequences of
hupS
and
hupL
clustered
R. leguminosarum
and
R. tropici hup
sequences together with those from
B. japonicum
and
Bradyrhizobium
sp. (
Lupinus
) strains, suggesting a common origin. In contrast,
Bradyrhizobium
sp. (
Vigna
)
hup
sequences diverged from the rest of rhizobial sequences, which might indicate that those organisms have evolved independently and possibly have acquired the sequences by horizontal transfer from an unidentified source.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Reference51 articles.
1. Albrecht, S. L., R. J. Maier, F. J. Hanus, S. A. Russell, D. W. Emerich, and H. J. Evans. 1979. Hydrogenase in Rhizobium japonicum increases nitrogen fixation by nodulated soybeans. Science203:1255-1257.
2. Arp, D. J. 1992. Hydrogen recycling in symbiotic bacteria, p. 432-460. In G. Stacey, R. H. Burris, and H. J. Evans (ed.), Biological nitrogen fixation. Chapman and Hall, New York, N.Y.
3. Generation of New Hydrogen-Recycling
Rhizobiaceae
Strains by Introduction of a Novel
hup
Minitransposon
4. Beringer, J. 1974. R factor transfer in Rhizobium leguminosarum. J. Gen. Microbiol.84:188-198.
5. Sequences and characterization of hupU and hupV genes of Bradyrhizobium japonicum encoding a possible nickel-sensing complex involved in hydrogenase expression
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