Agriculture Reference
In-Depth Information
out-of-date with respect to several recently reported species of nodulating bacteria,
discussed below.
4.1
-Proteobacteria
Table 4.1 lists the families and genera of
-Proteobacteria with nodulating species.
Ensifer
is considered in Garrity et al. (2004) as a genus separate from
Sinorhizobium
,
but this issue is still subject to intense discussion. On balance, Martens et al. (2007),
did not think the evidence for separation was yet sufficiently strong, but in 2008 they
appear to have changed their minds (Martens et al., 2008). Certainly new species are
being described under
Ensifer
(e.g.
E. mexicanus
, Lloret et al., 2007). In his compre-
hensive review of rhizobial ecology, Graham (2008) includes only one species under
Ensifer, E. adhaerens
, but note that this species is also considered by some to be
Sinorhi-
zobium
. Graham's review also gives citations for all species of rhizobia, from both
-Proteobacteria, and readers are referred to this work, except where species
have been described more recently. As Graham (2008) points out, “additions to this
list
-and
occur almost weekly” and several have been published during the writing of
this topic. Most of these are reported in the
International Journal of Systematic and Evo-
lutionary Microbiology
, and readers who wish to keep up-to-date are advised to check
this journal on line, as accepted papers are cited ahead of publication. The following
sections will consider individual genera and the hosts of the various species, in the
order in which the genera are listed in Table 4.1. In Tables 4.2 to 4.5 the rather small
number of legumes involved represents the way in which research has proceeded. In
general, people work on one or a few host species and identify the bacteria obtained
from their nodules. Compared with the total number of nodulated legumes this covers
only a very small minority of host plants.
By the time this volume is published there are likely to be more genera and species of
nodulating bacteria described, for example an as-yet-unnamed pink-pigmented genus
nodulating
Lotononis angolensis
(Yates et al., 2007).
...
Tab l e 4 . 1
Genera in the families of Rhizobiales with known nodulating members
Ensifer
and
Sinorhizobium
added together under
Sinorhizobium
Family
Genus
Species
Comments
Rhizobiaceae
Rhizobium
20
Several spp. have 2 or 3 biovars
Includes
Allorhizobium
Sinorhizobium
13
Shinella
1
Not fully authenticated
Bradyrhizobiaceae
Bradyrhizobium
8
Includes
Blastobacter
Hyphomicrobiaceae
Azorhizobium
2
Devosia
1
Methylobacteriaceae
Methylobacterium
2
Brucellaceae
Ochrobactrum
3
Phyllobacteriaceae
Mesorhizobium
16
Phyllobacterium
1-2
