Bacteria that are not rhizobia [Updated 14th September
2009]
This page lists bacteria that could be confused with
rhizobia. I define 'rhizobia' as "Bacteria capable of
forming symbiotic root nodules on legumes", other
definitions may differ. Naturally this is a continual work
in progress. As well as the categories below there are many
diverse species of bacteria that can fix nitrogen, but in a
free living state - not in root nodules. A few examples of
these are Rhodopseudomonas palustris,
Azospirillum sp., Azotobacter sp. and
many more. There are links on the left hand side of the
page to 'official' bacteria nomenclature websites
Agrobacterium
The Agrobacterium have been renamed as
Rhizobium species (Young et al. 2001),
they are listed below, with their new names. See the LPSN
for more information on the
Agrobacterium. These generally do not form
symbiotic root nodules, unless they harbour a Sym plasmid
or other transposable element with nodulation genes. In
this case, I would define them as rhizobia. Other
Agrobacterium have been reclassified as
Stappia, Ruegeria, and
Pseudorhodobacter.
Reference: YOUNG (J.M.), KUYKENDALL
(L.D.), MARTÍNEZ-ROMERO (E.), KERR (A.) and SAWADA
(H.): A revision of Rhizobium Frank 1889, with an
emended description of the genus, and the inclusion of all
species of Agrobacterium Conn 1942 and
Allorhizobium undicola de Lajudie et al.
1998 as new combinations: Rhizobium radiobacter,
R. rhizogenes, R. rubi, R.
undicola and R. vitis. Int. J. Syst.
Evol. Microbiol., 2001, 51, 89-103.
(Abstract)
| Old name |
New Name |
| Agrobacterium larrymoorei |
Rhizobium larrymoorei |
| Agrobacterium radiobacter =
Agrobacterium tumefaciens |
Rhizobium radiobacter |
| Agrobacterium rhizogenes |
Rhizobium rhizogenes |
| Agrobacterium rubi |
Rhizobium rubi |
| Agrobacterium vitis |
Rhizobium vitis |
Bacteria that are not rhizobia in "rhizobia
genera"
These may have names that suggest that they are
rhizobia, but have not been shown to form symbiotic root
nodules.
| Burkholderia unamae |
N2 fixing but does not form root nodules |
Bradyrhizobium betae
|
tumour forming bacteria |
Mesorhizobium thiogangeticum
|
Sulfur oxidising, nodulation unknown |
| Rhizobium selenitireducens |
selenite-reducing, isolated from bioreactor
(invalid name was: R. selenireducens) |
Rhizobium cellulosilyticum
|
unable to form nodules on tested legumes, but
does have nodD (Garcia-Fraile
et al, 2007) |
| Cohnella phaseoli |
Isolated from nodules, but cannot form root
nodules (Garcia-Fraile
et al, 2008) |
Names that have not been validly published or
revoked
These include names that have been submitted to the NCBI
database but not yet published, and names that were never
formally published. It also includes some names that were
vaild, but are no longer valid.
