Caracterización molecular de bacteria Azospirillum sp, Azotobacter sp y Pseudomonas sp. promotoras del crecimiento vegatal de cultivos de Solanum tuberosum y Zea mays

Abstract

With the aim of generating a native bank with Promoting Grow Plant Rhizobacteria (PGPR) and their later use as inoculates of the soils that diminishes the chemical fertilization, samples were taken from roots of cultures of potato (Solanum tuberosum Var Canchan) and of maize (Zea mayz Var Improved white) dealt with five types of fertilization: ovine, bovine guinea and pig manure, chemical fertilization and without fertilizer, of which strains of nitrogen-fixing bacteria corresponding to the genera Azospirillum, Azotobacter and Pseudomonas were isolated. The bacteria were differentiated on the basis of their morphology, generating power of auxins, phosphate solubilization, reaction to the  catalase, oxidasa and genetic similarity previous amplification of the region of rRNA 16S. The results show an ample genetic base that exhaustive need to be characterized and to be identified. The production of AIA in Azospirillum arrived until 120 levels of ppm; 118 ppm for the genera Azotobacter and 115 ppm in Pseudomonas fluorecens. Of selected strains, the DNA was sequenced, compared with Base of Data the GenBank and identified until species, such as Azospirillum brasilense; Azotobacter vinelandii, A. choccrococum, A. nigricans and A. salinestris. The sequences amplified with primer universal 9-27F and 1542R for the strains of Azospirillum, Azotobacter and Pseudomonas fluorescens used for this study are not reported in the data base of the GenBank.
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