Rhizobium

This article is about the bacterial genus. For the generic term that includes species in other genera, see Rhizobia.

Rhizobium
Rhizobium tropici on an agar plate (Tryptone — Yeast extract agar).
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Pseudomonadota
Class: Alphaproteobacteria
Order: Hyphomicrobiales
Family: Rhizobiaceae
Genus: Rhizobium
Frank 1889 (Approved Lists 1980)[1][2]
Type species
Rhizobium leguminosarum
(Frank 1879) Frank 1889 (Approved Lists 1980)
Species

See text

Rhizobium is a genus of Gram-negative soil bacteria that fix nitrogen. Rhizobium species form an endosymbiotic nitrogen-fixing association with roots of (primarily) legumes and other flowering plants.

The bacteria colonize plant cells to form root nodules, where they convert atmospheric nitrogen into ammonia using the enzyme nitrogenase. The ammonia is shared with the host plant in the form of organic nitrogenous compounds such as glutamine or ureides.[3] The plant, in turn, provides the bacteria with organic compounds made by photosynthesis. This mutually beneficial relationship is true of all of the rhizobia, of which the genus Rhizobium is a typical example.[4] Rhizobium is also capable of solubilizing phosphate.[5]

  1. ^ Frank, B. (1889). "Über die Pilzsymbiose der Leguminosen". Berichte der Deutschen Botanischen Gesellschaft. 7: 332–346.
  2. ^ Skerman, VB; McGowan, V; Sneath, PH (1980). "Approved lists of bacterial names". International Journal of Systematic Bacteriology. 30: 225–420. doi:10.1099/00207713-30-1-225.
  3. ^ Thilakarathna, Malinda S.; Raizada, Manish N. (2018-01-01). "Visualizing Glutamine Accumulation in Root Systems Involved in the Legume–Rhizobia Symbiosis by Placement on Agar Embedded with Companion Biosensor Cells". Phytobiomes Journal. 2 (3): 117–128. doi:10.1094/PBIOMES-07-18-0031-TA.
  4. ^ Sawada, Hiroyuki; Kuykendall, L. David; Young, John M. (June 2003). "Changing concepts in the systematics of bacterial nitrogen-fixing legume symbionts". The Journal of General and Applied Microbiology. 49 (3): 155–79. doi:10.2323/jgam.49.155. PMID 12949698.
  5. ^ Sridevi, M; Mallaiah, KV (March 2009). "Phosphate solubilization by Rhizobium strains". Indian Journal of Microbiology. 49 (1): 98–102. doi:10.1007/s12088-009-0005-1. PMC 3450048. PMID 23100757.