Living BeingsField guide · species
Rhizobium leguminosarum
(Frank 1879) Frank 1889 (Approved Lists 1980) emend. Ramirez-Bahena et al. 2008
Rhizobium leguminosarum links life in soil with nitrogen-fixing symbiosis in legume root nodules. Reaching a root, competing with neighboring microbes and surviving inside a nodule demand different traits. Much experimental work concerns identified strains and host plants; it should not be generalized to every bacterium historically assigned this name.
Public research profile · final editorial review pending.
Tree of lifeScientific lineage
- LifeLife
- DomainBacteria
- KingdomPseudomonadati
- PhylumPseudomonadota
- ClassAlphaproteobacteria
- OrderHyphomicrobiales
- FamilyRhizobiaceae
- GenusRhizobium
- SpeciesRhizobium leguminosarum
Advanced classification
Complete source lineage, including intermediate ranks. The standard view uses Life and the eight principal ranks.
- cellular organisms cellular root
- Bacteria domain
- Pseudomonadati kingdom
- Pseudomonadota phylum
- Alphaproteobacteria class
- Hyphomicrobiales order
- Rhizobiaceae family
- Rhizobium/Agrobacterium group no rank
- Rhizobium genus
- Rhizobium leguminosarum species
Structure and identification
Free-living cells are rod-shaped. Cells in a symbiotic nodule can differ physiologically from those growing outside the plant.
Habitat and range
Soil around a root, the root surface and the inside of a nodule are distinct environments. A pea-associated model study followed the bacterial requirements for growth and competition across these successive stages.
Nutrition and metabolism
Organic carbon supports free-living growth. Inside an effective nodule, plant resources support bacterial metabolism and nitrogen fixation. Experimental work identifies changing requirements for carbon processing and nutrient assimilation between colonization and the nitrogen-fixing bacteroid stage.
Biological activity
Nodulation signaling, motility, cell-envelope changes and metabolic adjustment contribute to colonization. A transposon-based study distinguished requirements shared across successive stages from requirements specific to root growth or nodule function.
Reproduction and life cycle
Cells divide outside the plant and may encounter a compatible root. Successful interactions progress through colonization and infection to nodule-associated development. The pea model also investigated release from nodules; host compatibility and strain identity are essential context.
Geographic distribution
Strain records occur across agricultural and natural settings. Host association and strain provenance should accompany detailed locality data.
Ecological role
Effective symbiosis makes atmospheric nitrogen available within the legume partnership. Competition around roots helps determine which bacteria establish the interaction, connecting free-living survival with the later nutritional benefit to the plant.
Distinctive adaptations
Sequenced strain 3841 has a chromosome and multiple plasmids. Its genome study distinguishes a broadly shared core from more variably distributed accessory components, helping explain why bacteria with shared cellular ancestry can differ in ecological capabilities.
Evidence
Sources
- Rhizobium leguminosarum · NCBI Taxonomy ↗NCBI
- Lifestyle adaptations of Rhizobium from rhizosphere to symbiosis ↗Proceedings of the National Academy of Sciences of the United States of America · 2020
- The genome of Rhizobium leguminosarum has recognizable core and accessory components ↗Genome biology · 2006
Connected life
Relationships
No reviewed ecological connections in the collection yet.
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