Identification and functional characterization of genes involved in carbon source utilization in A brasilense Sp7

Abstract

Members of the Genus Azospirillum are widely distributed including tropical [Dobereiner et al., 1976], sub-tropical and temperate [Haahtela et al., 1981] regions of the world. They colonize the rhizosphere, rhizoplane and at times root interior of a large variety of cereals and grasses. Together with other nitrogen-fixing, non-sulphur, purple, phototrophic bacteria Azospirillum forms a phylogenetic subgroup within the and#940;-subclass of proteobacteria. They promote plant growth by fixing nitrogen and producing phytohormones such as IAA, gibberellic acid and cytokinin, and displacement of plant pathogenic fungi and bacteria by anti-microbial activity. Bacterial nitrite production also improves formation of lateral roots which results in enhanced mineral and water uptake. The application of Azospirillum inoculants as a green fertilizer has been carried out with considerable success [Okon and Labandera-Gonzalez, 1994]. They can act as potential alternative or complement to the chemical nitrogen fertilizer that has given rise to several concerns such as exhaustion of non-renewable sources and emission of NO2 and NO from the soil and NO3 leaching which has severe environmental consequences. newline