Isolation of the Azospirillum Species from the Rhizosphere of the Leguminous Bauhinia petersiana in North Eastern Namibia

摘要

Bacteria associated with the plant roots of leguminous plants have the potential to alleviate the burden of using costly and harmful agrochemicals. Discovery of novel and suitable bacteria for enhancing plant growth is amongst the primary challenges involved in realizing the agronomic application of plant beneficial bacteria. A bacterium isolated from the rhizospheric soil of the legume Bauhinia petersiana was described based on several physiological and molecular analyses. The gram-negative bacterium designated as LMAB10 is motile, oxidase positive, catalase negative and displayed lipolytic activity. The bacterium’s ability to utilize fourteen compounds as sole carbon sources was examined. A 340 kb fragment of the structural nifH gene that encodes for the Fe protein polypeptide of the nitrogenase was amplified from the genomic DNA of isolate LMAB10. Identification of the isolate via 16s rDNA via the BLASTn revealed that the isolate is an Azospirillum species with a 98 % similarity to Azospirillum oryzae JCM 21588T. Phylogenetic analyses with MEGA5 software showed that the isolate shares an ancestor with Azospirillum oryzae JCM 21588T and Azospirillum zeae N7T, eventually branching off into a separate taxon. The partially-described isolate from the rhizosphere of B. petersiana shows promise for use as a crop inoculant.