Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes. To express genes for nitrogen fixation, rhizobia require a plant host; they cannot i
Root nodules, each containing billions of Rhizobiaceae bacteria
Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship
Indeterminate nodules growing on the roots of Medicago italica
Cross section through a soybean root nodule. The bacterium, Bradyrhizobium japonicum, colonizes the roots and establishes a nitrogen fixing symbiosis. This high magnification image shows part of a cell with single bacteroids within their symbiosomes. In this image, endoplasmic reticulum, dictysome and cell wall can be seen.