From Simple English Wikipedia, the free encyclopedia

Bradyrhizobium is a genus of Gram-negative soil bacteria that naturally occur as free-living soil bacteria or in symbiotic relationships with legumes. Bradyrhizobium is known for nitrogen fixation, which converts atmospheric nitrogen into ammonia (N2 - NH3). This process allows plants and other organisms to use organic compounds, such as nitrates, more readily.[1][2] Nitrogen-fixing bacteria such as Bradyrhizobium are crucial to chemical cycles in the soil.

Microbiology[change | change source]

Ecology[change | change source]

Bradyrhizobium species are Gram-negative, rod-shaped (also called bacilli) with a flagella (like a tail) to help them move through their environment. Gram-negative bacteria are smaller types of bacteria with thin cell walls that are sensitive to drought or water stress.[3] They are commonly found in the soil where they can form relationships with plant roots such as peas, clover, and other legumes in a mutually beneficial, or symbiotic, relationship. In exchange for their nitrogen fixation, the Bradyrhizobium benefit from carbohydrates made by the plant. They are also common in forest soils, although these species tend not to fix nitrogen.[4]

Taxonomy[change | change source]

Accepted species[change | change source]

Bradyrhizobium genus comprises the following species:[5]

Provisional Species[change | change source]

The following species have been published, but not validated according to the Bacteriological Code[5]

  • "B. brasilense" Martins da Costa et al. 2017
  • "B. campsiandrae" Cabral Michel et al. 2021
  • "B. centrolobii" Michel et al. 2017
  • "B. forestalis" Martins da Costa et al. 2018
  • "B. guangzhouense" Li et al. 2019
  • "B. macuxiense" Michel et al. 2017
  • "B. sacchari" de Matos et al. 2017
  • "Photorhizobium thompsonianum" Eaglesham et al. 1990[8]
  • "B. uaiense" Cabral Michel et al. 2020
  • "B. valentinum" Durán et al. 2014
  • "B. zhanjiangense" Li et al. 2019

References[change | change source]

  1. Wagner, S. C.. (2011) Biological Nitrogen Fixation. Nature Education Knowledge 3(10):15
  2. Wongdee, J., Boonkerd, N., Teaumroong, N., Tittabutr, P., & Giraud, E. (2018). Regulation of Nitrogen Fixation in Bradyrhizobium sp. Strain DOA9 Involves Two Distinct NifA Regulatory Proteins That Are Functionally Redundant During Symbiosis but Not During Free-Living Growth. Frontiers in microbiology, 9, 1644.
  3. Hoorman, James J. (June 6, 2016). "Role of Soil Bacteria". The Ohio State University: College of Food, Agriculture, and Environmental Sciences. Retrieved July 2, 2023.
  4. VanInsberghe, David; Maas, Kendra R.; Cardenas, Erick; Strachan, Cameron R.; Hallam, Steven J.; Mohn, William W. (November 2015). "Non-symbiotic Bradyrhizobium ecotypes dominate North American forest soils". The ISME journal. 9 (11): 2435–2441. doi:10.1038/ismej.2015.54. ISSN 1751-7370. PMC 4611507. PMID 25909973.
  5. 5.0 5.1 "Genus: Bradyrhizobium". Retrieved 2023-05-05.
  6. 6.0 6.1 6.2 "Bradyrhizobium agreste sp. nov., Bradyrhizobium glycinis sp. nov. and Bradyrhizobium diversitatis sp. nov., isolated from a biodiversity hotspot of the genus Glycine in Western Australia". Int J Syst Evol Microbiol. 71 (3). 2021. doi:10.1099/ijsem.0.004742. PMC 8375429. PMID 33709900. {{cite journal}}: Cite uses deprecated parameter |authors= (help)
  7. 7.0 7.1 Kalita, M; Małek, W (2010). "Genista tinctoria microsymbionts from Poland are new members of Bradyrhizobium japonicum bv. genistearum". Systematic and Applied Microbiology. 33 (5): 252–9. doi:10.1016/j.syapm.2010.03.005. PMID 20452160.
  8. Eaglesham AR, Ellis JM, Evans WR, Fleishman DE, Hungria M, Hardy KW (1990). "The first photosynthetic N2-fixing Rhizobium: Characteristics". In Gresshoff PM, Koth LE, Stacey G, Newton WE (eds.). Nitrogen Fixation: Achievements and Objectives. Boston, MA: Springer. pp. 805–811. doi:10.1007/978-1-4684-6432-0_69. ISBN 978-1-4684-6434-4.