''Azorhizobium'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. They fix nitrogen in

symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

with plants in the genus ''

Sesbania ''Sesbania'' is a genus of flowering plants in the pea family, Fabaceae, and the only genus found in tribe Sesbanieae. Riverhemp is a common name for plants in this genus. Notable species include the rattlebox ('' Sesbania punicea''), spiny sesb ...

''. Strain ORS571 of ''A. caulinodans'' has been fully sequenced. ''Azorhizobium'' ''caulinodans'' ORS571 has exceptional properties because it is able to fix nitrogen in both aerobic free-living and symbiotic states ''Azorhizobium caulinodans'' ORS571 is a rice and wheat endophyte, and does not need plant metabolites to make functional nitrogenase, but low nitrogenase expression is observed when it is living in cereal roots.

References

Hyphomicrobiales Bacteria genera {{Hyphomicrobiales-stub