A taxonomic study of the Spirillum lipoferum group, with descriptions of a new genus, Azospirillum gen. nov. and two species, Azospirillum lipoferum (Beijerinck) comb. nov. and Azospirillum brasilense sp. nov.

Abstract

Sixty-one strains of the root-associated nitrogen fixer Spirillum lipoferum exhibited a similar morphology in peptone--succinate salts medium: vibrioid cells having a diameter of 1.0 micrometer. When grown in broth the cells had a single polar flagellum, but when grown on agar at 30 degrees C lateral flagella of shorter wavelength were also formed. The DNA base composition was 69--71 mol% guanine + cytosine when determined by thermal denaturation. DNA homology experiments indicated the occurrence of two distinct but related homology groups: 46 strains were in group I and 15 strains were in group II. Group II strains were distinguished by their ability to use glucose as a sole carbon source for growth in nitrogen-free medium, by their production of an acidic reaction in a peptone-based glucose medium, by their requirement for biotin, and by their formation of wider, longer, S-shaped or helical cells in semisolid nitrogen-free malate medium. The results indicate that two species exist, and on the basis of their characteristics it is proposed that they be assigned to a new genus, Azospirillum. Strians belonging to group II are named A. lipoferum (Beijerinck) comb. nov., while those belonging to group I are named A. brasilense sp. nov. Strain Sp 59b (ATCC29707) is proposed as the neotype strain for A. lipoferum, and strain Sp 7 (ATCC 29145) is proposed as the type strain for A. brasilense.

Characterization of cell surface components of Azospirillum brasilense Sp7 as antigenic determinants for strain-specific monoclonal antibodies

“…It is most remarkable that A. brasilense strains Sp7 and Cd can be distinguished by mAbs against lipopolysaccharide and against the 85 kDa outer-membrane protein, since both strains are very closely related. Strain Cd was isolated from Cjnodon dacolon roots in California after inoculation with strain Sp7 (Tarrand et al, 1978). Strains Sp7 and Cd showed only very slight or no difference in restriction fragment length polymorphism, which usually allows a strain-specific identification (Fani e t al., 1991 ;Gundisch e t al., 1993).…”

Biological Nitrogen Fixation

“…Dentro de las relaciones favorables se encuentra la asociación con bacterias fijadoras de nitrógeno; entre estas, especies de Azospirillum 1 , Enterobacter, Klebsiella, Pseudomonas y Burkholderia (Estrada et al, 2001 (Tarrand et al,1978;Magelhaes et al, 1983;Reinhold et al, 1987;Khammas et al, 1989;Sly y Stackebrandt, 1999;Eckert et al, 2001); desde entonces ha sido aislada de varias especies cultivadas y silvestres y de varios tipos de suelo.…”

Ocorrência e diversidade de bactérias diazotróficas associadas a gramíneas forrageiras do Pantanal Sul Matogrossense

“…(1) Conforme descrito no Manual de Bergey´s (1994) e descrição das espécies (Tarrand et al, 1978, Magalhães et al, 1983e Baldani et al, 1986. (2) Braquiária (Brachiaria humidicola); capim mimoso (Axonopus purpusii); capim carona (Elyonurus muticus).…”