In Azospirillum brasilense ADP-ribosylation of dinitrogenase reductase (NifH) occurs in response to addition of ammonium to the extracellular medium and is mediated by dinitrogenase reductase ADP-ribosyltransferase (DraT) and reversed by dinitrogenase reductase glycohydrolase (DraG). The P(II) proteins GlnB and GlnZ have been implicated in regulation of DraT and DraG by an as yet unknown mechan...

Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct ...

Disruption of an open reading frame (ORF) of 840 bp (280 amino acids; ORF280) in an Azospirillum brasilense Tn5 mutant resulted in a pleiotrophic phenotype. Besides an enhanced N(2)-fixing capacity and altered expression pattern of a nifH-gusA fusion, growth on the charged polar amino acids glutamate and arginine was severely affected. ORF280, similar to previously identified ORFs present in Br...

The effect of the microalgae-growth promoting bacterium Azospirillum brasilense on accumulation of total carbohydrates and starch in two species of Chlorella (Chlorella vulgaris and Chlorella sorokiniana), when the bacterium and each microalga were jointly immobilized in alginate beads was studied under autotrophic conditions for 144 h in synthetic medium. The interaction of the bacterium with ...

in order to evaluate the effects of different planting dates and biological fertilizers on yield, yield components and essential oil content in cumin (cuminum cyminum) and fenugreek (trigonella foenum-graecum) intercropping, an experiment was conducted in a split-plot factorial arrangement in a randomized complete block design with three replications in research farm of ferdowsi university of m...

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...

During the last 35 years of studies of Azospirillum–plant interaction, over 20 proposals were suggested for the mechanism of action by which Azospirillum spp., the most intensively studied plant growth-promoting bacteria, enhances plant growth. The proposals include a single phytohormone activity, multiple phytohormones, nitrogen fixation, assortments of small-sized molecules and enzymes, enhan...

A lepidopteran toxin gene, cryIC (pSB607) from entomopathogenic Bacillus thuringiensis subsp. aizawai was introduced into nitrogen-fixing Azospirillum lipoferum by transformation. Regeneration of spheroplasts was achieved at 99% with 39% frequency of regeneration. Transformants were screened on NB kanamycin with ampicillin plates and 4 transformants were selected after ten generations. SDS-PAGE...

Azospirillum brasilense Sp7 and its ntrA (rpoN), ntrBC, and ntrC mutants have been evaluated for their capabilities of poly-3-hydroxybutyrate (PHB) accumulation in media with high and low ammonia concentrations. It was observed that the ntrBC and ntrC mutants can produce PHB in both low- and high-C/N-ratio media, while no significant PHB production was observed for the wild type or the ntrA mut...