''Rhizobium leguminosarum'' is a bacterium which lives in a
mutualistic symbiotic relationship with
legume
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
s, and has the ability to
fix free nitrogen from the air.
''R. leguminosarum'' has been very thoroughly studied—it has been the subject of more than a thousand publications.
Morphology
''Rhizobium leguminosarum'' is a Gram-negative, motile, rod-shaped, aerobic bacterium.
Common biovars
''Rhizobium leguminosarum'' biovar ''trifolii'', and ''R. leguminosarum'' biovar ''viciae'' are the most commonly studied
biovar
A biovar is a variant prokaryotic strain that differs physiologically or biochemically from other strains in a particular species. Morphovars (or morphotypes) are those strains that differ morphologically. Serovars (or serotypes) are those strain ...
s of ''R. leguminosarum'', with certain studies seemingly treating ''R. trifolii'' as its own species.
Fatty acid synthesis
''Rhizobium leguminosarum''s
acyl carrier protein
The acyl carrier protein (ACP) is a cofactor of both fatty acid and polyketide biosynthesis machinery. It is one of the most abundant proteins in cells of ''E. coli.'' In both cases, the growing chain is bound to the ACP via a thioester derived fro ...
differs from most ACPs by having a
C-terminus
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...
extension. This ACP is also used in the synthesis of unusually long ACPs which themselves are then used in the synthesis of the ''R. leguminosarum''
nod factor
Nod factors (nodulation factors or NF), are signaling molecules produced by soil bacteria known as rhizobia in response to flavonoid exudation from plants under nitrogen limited conditions. Nod factors initiate the establishment of a symbiotic re ...
.
Uses
''R. leguminosarum'' is widely used in the inoculation of legume seeds. The sv. trifolii strain U204 is commercially used to inoculate white and red clover in particular, but better strains for this purpose are being developed.
Research has been carried out into the role that ''R. leguminosarum'' could play in promoting growth of canola and lettuce.
References
External links
Type strain of ''Rhizobium leguminosarum'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Rhizobiaceae
{{Hyphomicrobiales-stub