Genetic data suggest that the oligotrophic freshwater bacterium Caulobacter crescentus metabolizes D-xylose through a pathway yielding alpha-ketoglutarate, comparable to the recently described L-arabinose degradation pathway of Azospirillum brasilense. Enzymes of the C. crescentus pathway, including an NAD(+)-dependent xylose dehydrogenase, are encoded in the xylose-inducible xylXABCD operon (C...

Restriction analysis of amplified 16S rDNA from bacterial strains isolated from soil was used to evaluate the effects of swine manure and urea fertilisation on indigenous populations of the plant growth promoting bacterium, Azospirillum brasilense, in corncultivated experimental plots. Several operational taxonomic units (OTUs) were found among the isolates. One of them, identified as A. brasil...

Batch and fed batch cultures of Azospirillum brasilense Sp245 were conducted in a bioreactor. Growth response, IAA biosynthesis and the expression of the ipdC gene were monitored in relation to the environmental conditions (temperature, availability of a carbon source and aeration). A. brasilense can grow and produce IAA in batch cultures between 20 and 38 degrees C in a standard minimal medium...

The elemental composition of strawberry plants (Fragaria ananassa cv. Macarena) inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, and non-inoculated controls, was studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. This allowed simultaneous semi-quantification of different elements in a small, solid sample. Plants were in...

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the in...

Azospirillum sp. are bacteria beneficial to inoculated plants, and the effect is partially attributed to gibberel lin production. Deutero-labelled GA9 was fed to dy mutant rice-dwarf seedlings inoculated with A. lipoferum or A. brasilense and/or treated with Prohexadione-Ca, an inhibitor of late steps in gibberellin biosynthesis. According to the shoot growth response, the mutant showed the abi...

The present study focused on isolation and characterization of Azospirillum sp. from paddy field soils of Thanjavur (Dt), Tamil Nadu. The physico-chemical characteristics of the soil samples were analysed by using standard methods. Totally nine native strains of Azospirillum were isolated. Among the nine isolated strains three strains were belonging to Azospirillum amazonense and six strains be...

The effects of 10, 50, 100, 200 and 300 ìg mlÿ1 of bromopropylate and methidathion were investigated in the cells of Azospirillum brasilense grown in chemically de®ned media and dialysed-soil media. The insecticide bromopropylate did not affect microbial growth, the levels of ATP and dinitrogen ®xation of A. brasilense in either chemically de®ned media or dialysedsoil media. Methidathion signi®...

Azospirillum represents the best characterized genus of plant growth-promoting rhizobacteria. Other free-living diazotrophs repeatedly detected in association with plant roots, include Acetobacter diazotrophicus, Herbaspirillum seropedicae, Azoarcus spp. and Azotobacter. Four aspects of the Azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fi...