Regresar

Rhizospheric rhizobia identification in maize (Zea mays l.) plants

Abstract:

Rhizobia have been studied for the symbiosis that they establish with the roots of legumes. However, the colonization and promotion of growth in non-leguminous plants has also been demonstrated. The aim of this work was the biochemical and molecular identification of rhizosphere rhizobia present in the rhizosphere of two commercial maize cultivars. Cultivable isolates were obtained in yeast-mannitol-agar (YMA) medium from rhizospheric soil and the rhizoplane. The cultural (size, color, mucus, etc.), morphological, and staining (cell shape, response to staining and sporulation) characteristics were determined, as well as isolate responses to eight biochemical tests (acid-base production, citrate, oxidase, catalase, H2S production, urease, gelatinase and the oxidative-fermentative assay) that are valuable for rhizobia identification. The genus was determined by 16S rDNA gene sequencing. We obtained 81 total isolates of which 30.86% showed the cultural, morphological and staining characteristics expected for rhizobia and only 20% of these corresponded to the genus Rhizobium.