Azospirillum

Abstract

A . zo . spi . ril ' lum . Fr. n. azote nitrogen; Gr. n. spira a spiral; M.L. dim. neut. n. spirillum a small spiral; Azospirillum a small nitrogen spiral. Proteobacteria / Alphaproteobacteria / Rhodospirillales / Rhodospirillaceae / Azospirillum Plump , slightly‐curved and straight rods , 0 . 6–1 . 7 × 2 . 1–3 . 8 µm , often with pointed ends. Intracellular granules of poly‐β‐hydroxybutyrate are present. Enlarged, pleomorphic forms may occur in old, alkaline cultures, under conditions of excess oxygen or other stress. Gram negative to Gram variable. Motile in liquid media by a single polar flagellum ; on solid media at 30°C, numerous lateral flagella of shorter wavelength may also be formed. Nitrogen fixers , exhibiting N 2 ‐dependent growth under microaerobic conditions . Grow well under an air atmosphere in the presence of a source of fixed nitrogen such as an ammonium or glutamate salts. Cells previously grown in presence of an inorganic nitrogen source may fix nitrogen in air provided that all added nitrogen is exhausted and nitrogenase is derepressed. Possess mainly a respiratory type of metabolism with oxygen and, with some strains, nitrate or nitrite as the terminal electron acceptor. Fermentative metabolism may also occur. Under severe oxygen limitation , some strains may dissimilate nitrate to nitrite or to nitrous oxide and nitrogen gas . Optimal temperature for growth varies from 33 to 41°C and pH from 5.5 to 7.5. Some strains may grow and form light or dark pink colonies, often wrinkled and non‐slimy, on potato agar. Oxidase positive. Chemoorganotrophic; some strains are facultative hydrogen autotrophs. Grow well on salts of organic acids such as malate , succinate , lactate or pyruvate . d ‐ fructose and certain carbohydrates may also serve as carbon sources . Some species require biotin. Growth in presence of 3% NaCl has been observed for some species. Occur free‐living in the soil or associated with the roots , stems , leaves , and seeds mainly of cereals and forage grasses, although they have also been isolated from coconut plants, vegetables, fruits, legume, and tuber plants. May also be found in freshwater lakes. Root nodules are not induced. The mol % G + C of the DNA is : 64–71. Type species : Azospirillum lipoferum (Beijerinck 1925) Tarrand, Krieg and Döbereiner 1979, 79 (Effective publication: Tarrand, Krieg and Döbereiner 1978, 978) ( Spirillum lipoferum Beijerinck 1925, 353.)

The functional microbiome of arthropods

“…The distribution of taxa in soil microbiome, however, was represented in green colour irrespective of abundance levels. Note the presence of clusters around nitrogen fixing Rhizobiales (top), Bradyrhizobiaceae plus some Rhodobacterales (middle) and within the orders of Sphingomonadales, Rhodospirillales and Rickettsiales (middle to bottom), in agreement with phenotypic information [ 73 ]. Rickettsiales are rendered in yellow over black background to underlie their nature of endocellular parasites.…”

“…Moreover, dissimilatory nitrate reduction often lacks key terminal enzymes when analyzed in animal microbiomes [ 42 ]. Complementary information on functional traits was taken from Bergey’s manual [ 73 ].…”

Genotypic Variation of Endophytic Nitrogen-Fixing Activity and Bacterial Flora in Rice Stem Based on Sugar Content

“…Bootstrap values of ≥50% are indicated at their respective nodes. Reference type strains are indicated with superscript “†.” The backgrounds of the reference strains are colored according to the sugar (sucrose and/or glucose) utilization capacity of those bacteria based on the data from (1) Lee et al ( 2013 ); (2) Staley ( 1984 ); (3) Kuykendall et al ( 2015 ); (4) Dall'Agnol et al ( 2013 ); (5) Baldani et al ( 2015 ); (6) Hungria et al ( 1993 ); (7) Kuykendall ( 2015 ); (8) Sajnaga and Jach ( 2020 ); (9) Ahnia et al ( 2018 ); (10) Reis et al ( 2004 ); (11) Chen et al ( 2006 ); (12) Coenye et al ( 2001 ); (13) Wolterink et al ( 2005 ); (14) Weon et al ( 2008 ); (15) Qiu et al ( 2017 ); (16) Hardoim et al ( 2013 ); (17) Xu et al ( 2020 ); (18) Ueki et al ( 2006 ); (19) Olsen ( 2015 ); (20) Imhoff ( 2015b ); (21) Diaz-Barrera et al ( 2016 ); (22) Bae et al ( 2006 ); (23) Norris et al ( 2015 ); and (24) Patrick and McDowell ( 2015 ). The black-and-white shading in the columns on the right-hand of the NifH-OTU name indicates the mean relative abundance of the NifH-OTUs in each rice genotype ( n = 2 for Nipponbare; n = 3 for agpl1 , Leafstar, and CG14).…”

Root Growth-Promoting Effect in Wheat Plants Exerted by Azospirillum Argentinense Rec3, Its Flagellar Protein Azflap and a Strawberry Hydroalcoholic Extract in a Simple Rhizotron System

“…Azospirillum is an alpha proteobacteria that belongs to the order Rhodospirillales and the family Azospirillaceae (Baldani et al, 2015). This genus is part of the well-known Plant Growth Promoting Rhizobacteria (PGPR), which are a group of bacteria that enhance plant performance through various mechanisms, such as biological nitrogen fixation and hormone production, among others (Saad et al, 2020); and they can also improve plant tolerance to different diseases (Fujita et al, 2017;Viejobueno et al, 2021).…”