''Azospirillum brasilense'' is a well studied,

nitrogen-fixing Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmos ...

(

diazotroph Diazotrophs are bacteria and archaea that fix gaseous nitrogen in the atmosphere into a more usable form such as ammonia. A diazotroph is a microorganism that is able to grow without external sources of fixed nitrogen. Examples of organisms that ...

), genetically tractable, Gram-negative, alpha-proteobacterium bacterium, first described in Brazil (in a publication in 1978) by the group of

Johanna Döbereiner Johanna Liesbeth Kubelka Döbereiner (28 November 1924 – 5 October 2000) was a Brazilian agronomist. Biography Döbereiner was born in Ústí nad Labem, Czechoslovakia on the 28 November 1924. Her family were German Czechoslovakians from Auss ...

and then receiving the name "brasilense". ''A. brasilense'' is able to fix nitrogen in the presence of low oxygen levels, making it a microaerobic diazotroph. An isolate from the genus ''

Azospirillum ''Azospirillum'' is a Gram-negative, microaerophilic, non- fermentative and nitrogen-fixing bacterial genus from the family of Rhodospirillaceae. ''Azospirillum'' bacteria can promote plant growth. Characteristics The genus ''Azospirillum'' ...

'' was isolated from nitrogen poor soils in the Netherlands in 1925, however the species ''A. brasilense'' was first described in 1978 in Brazil, since this genus is widely found in the

rhizosphere The rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome. Soil pores in the rhizosphere can contain many bacteria and other microor ...

s of grasses around the world where it confers plant growth promotion. Whether growth promotion occurs through direct nitrogen flux from the bacteria to the plant or through hormone regulation is debated. The two most commonly studied strains are Sp7 (ATCC 29145) and Sp245, both are Brazilian isolates isolated from Tropical grasses from Seropedica, Brazil. The genome of ''A. brasilense'' Sp245 has been sequenced and is 7Mbp in size and spread across 7 chromosomes. The high GC content (70%) makes it challenging to engineer. Sp245 can be transformed with OriV origin of replication

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; how ...

s through

conjugation Conjugation or conjugate may refer to: Linguistics * Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics * Complex conjugation, the chang ...

and

electroporation Electroporation, or electropermeabilization, is a microbiology technique in which an electrical field is applied to cells in order to increase the permeability of the cell membrane, allowing chemicals, drugs, electrode arrays or DNA to be introdu ...

. The strain is natively resistant to both

spectinomycin Spectinomycin, sold under the tradename Trobicin among others, is an antibiotic useful for the treatment of gonorrhea infections. It is given by injection into a muscle. Common side effects include pain at the area of injection, rash, nausea, f ...

and

ampicillin Ampicillin is an antibiotic used to prevent and treat a number of bacterial infections, such as respiratory tract infections, urinary tract infections, meningitis, salmonellosis, and endocarditis. It may also be used to prevent group B strepto ...

antibiotics.

Kanamycin Kanamycin A, often referred to simply as kanamycin, is an antibiotic used to treat severe bacterial infections and tuberculosis. It is not a first line treatment. It is used by mouth, injection into a vein, or injection into a muscle. Kanamycin ...

resistance is used as a selectable marker. ''A. brasilense'' has a high evolutionary adaptation rate driven by codon mutation and

transposon A transposable element (TE, transposon, or jumping gene) is a nucleic acid sequence in DNA that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size. Transpo ...

hopping.

A strain originally classified as ''Roseomonas fauriae'' was reclassified as ''A. brasilense''. It was first isolated from a hand wound of a woman in Hawaii in 1971, and was named for Yvonne Faur "for her contributions to public health bacteriology and, specifically, for her contribution to the recognition of pink-pigmented bacteria."Rihs JD, Brenner DJ, Weaver RE, Steigerwalt AG, Hollis DG, Yu VL
Roseomonas, a new genus associated with bacteremia and other human infections.
Journal of clinical microbiology. 1993 Dec 1;31(12):3275-83.

References

External links

* *Swędrzyńska, D. "Effect of inokulation with Azospirillum brasilense on development and yielding of winter wheat and oat under different cultivation."Polish Journal of Environmental Studies 9.5 (2000): 423–428. *

External links

*
Type strain of ''Azospirillum brasilense'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{DEFAULTSORT:Azospirillum brasilense Rhodospirillales Bacteria described in 1978