Wiktionary
rhizobia
n. (plural of rhizobium English)
WordNet
rhizobia
See rhizobium
Wikipedia
Rhizobia
Rhizobia are soil bacteria that fix nitrogen ( diazotrophs) after becoming established inside root nodules of legumes ( Fabaceae). In order to express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In general, they are Gram-negative, motile, non- sporulating rods.