Bactérias solubilizadoras de fosfato em solo rizosférico da Caatinga

Abstract

The ecological relationship between plants and microorganisms is well known, however the biotechnological potential of microorganisms from semiarid soils is still underexploited. Thus, the aim of this study was to quantify and identify phosphate solubilizing bacteria (CaHPO4), contained onto cactus roots of genus Cereus, collecfrom Caatinga biome (city of Irauçuba, state of Ceará). To achieve this goal, it was quantified Cultivable Heterotrophic Bacteria (CHB) and Phosphate-solubilizing Bacteria (PSB) by standard plate count method (SPC), utilizing plate count agar (PCA) and GL agar, respectively. Also, it was performed Gram staining testing, catalase, O/F to glucose and aggregation to phenotypic characterization of isolated strains. The CHB and PSB presented values of 4,62×107 CFU/g and 3,475×107 CFU/g, respectively. A percentage of 75% of the PSB population comprises the full microbiota found on the root samples of Cereus. It was observed that 73% of strains had morphology of Gram negative rods, 18% of Gram-positive rods and 9% of gram-positive cocci. The most strains (91%) showed oxidative/fermentation metabolism to glucose (O/F) and presence of catalase enzyme, while glass aggregation ability was observed in all tested strains. Therefore, new researches should be encouraged in order to increase knowledge of biotechnological potential of bacteria from caatinga's soil and provide subsidies to develop strategies for the improvement of fertilization efficiency and plant development.