are soil bacteria that fix nitrogen (diazotrophy) after becoming
established inside root nodules of legumes (Fabaceae).
several different genera of rhizobia. All of them belong to the
Rhizobiales, a probably-monophyletic group of proteobacteria.
bacteria are a group of soil based microorganisms (SBO's) which
establish symbiotic relationships with legumes.
SBO's form nodules on the roots of the legumes and provide
nitrogen to the plants.
Conventional methods of providing nitrogen to plants include (1)
adding nitrogen fertilizers to the soil, or (2) inoculating
(coating) seed with nitrogen fixing bacteria. Nitrogen fixing
bacteria convert atmospheric nitrogen to an inorganic form that
is useable by plants.
bacterium’s enzyme system supplies a constant source of reduced
nitrogen to the
host plant and the plant furnishes nutrients and energy for the
activities of the bacterium. About 90% of legumes can become