Azospirillum amazonense revealed genomic organization patterns of the nitrogen fixation genes similar to those of the distantly related species A. brasilense. Our work suggests that A. brasilense nifHDK, nifENX, fixABC operons and nifA and glnB genes may be structurally homologous to the counterpart genes of A. amazonense. This is the first analysis revealing homology between A. brasilense nif ...

Inoculation of Phaseolus vulgaris with Azospirillum brasilense Cd promoted root hair formation in seedling roots and significantly increased total and upper nodule numbers at different concentrations of Rhizobium inoculum. In experiments carried out in a hydroponic system, A. brasilense caused an increase in the secretion of nod gene-inducing flavonoids, as was observed by nod gene induction as...

NifA protein activates transcription of nitrogen fixation operons by the alternative sigma 54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS) located at the -200/-100 position of nif promoters with the consensus motif TGT-N10-ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-transferase (GST)-NifA fusion pr...

Seedlings of Arabidopsis thaliana, Columbia ecotype, were used in vitro to analyze root hair growth response to inoculation by the plant-growth-promoting rhizobacterium, Azospirillum brasilense Sp-245. Root hair length was measured at physiologically-identical stages of root growth. In seedlings inoculated with A. brasilense, root hairs were more than twice the length of those of the non-inocul...

A simple time-limited liquid enrichment procedure to aid in the quantitative detection of very few cells of Azospirillum brasilense in plant roots is described. The method is based on limited multiplication of A. brasilense in convential semi-solid medium and counting of the bacteria in the enriched medium by enzyme-linked immunosorbent assay (ELISA) or by Most Probable Number (MPN) techniques....

Inoculation of wheat with Azospirillum brasilense, combined with the application of four fungal and bacterium-inhibiting substances to which A. brasilense is resistant in the soil, decreased the rhizosphere population, while it increased wheat root colonization by A. brasilense, even in cases of poor inoculation. The inoculation significantly increased the following wheat plant parameters as we...

Azospirillum is a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide. Azospirillum brasilense strains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2 fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of ...

Azospirillum brasilense, a nitrogen-fixing bacterium found in the rhizosphere of various grass species, and increased the plant growth by growth substances produced by the bacteria like indole acetic acid and indole lactic acid which produced by A. brasilense from tryptophan (Tien et al., 1979; Okon and Vanderleyden, 1997; Bashan et al., 2004). Evaluation of 20 years of data indicated that 60 7...

Azospirillum brasilense is a nitrogen-fixing bacterium living in association with plant roots. The genome of the strain Sp245, isolated in Brazil from wheat roots, consists of one chromosome and six plasmids. In this work, the A. brasilense Sp245 plasmids were analyzed in order to shed some light on the evolutionary pathways they followed over time. To this purpose, a similarity network approac...

An Azospirillum brasilense mutant (N12) pleiotropically defective in the assimilation of nitrogenous compounds (Asm-) was isolated and found lacking in the glutamate synthase (GOGAT-). The glt (GOGAT) locus of A. brasilense was identified by isolating a broad-host-range pLAFR1 cosmid clone from a gene library of the bacterium that rectified Asm- and GOGAT- defects (full recovery of activities o...