Plant growth-promoting rhizobacteria are microorganisms that inhabit the soil and are often isolated from the rhizosphere of several cultivated plants. The effects of these bacteria on plant growth are broad, including the beneficial effects on the control of phytopathogens in the soil, growth and alleviation of abiotic stresses in plants. Among the species mentioned in this group, the genera Pseudomonas, Bacillus stand out. Bradyrhizobium and Rhizobium. There are few studies on the ecology of these bacteria in sandy soils, which are characterized as having low levels of organic matter and risks for grain cultivation and also colonizing the rhizosphere of pastures. In this context, the isolation of Bacillus sp. of rhizospheric soil from pastures in integrated systems with soybean in sandy soils in western São Paulo. Plants will be collected in an experimental area with a five-year history of integrating livestock farming, in the municipality of Caiuá-SP, where the following treatments are successively conducted: Soy- Urochloa brizantha cv piatã; Soy- Maize- Urochloa brizantha cv piatã and Perennial pasture of Urochloa brizantha cv piatã. After the rhizosphere isolation, the bacteria will be characterized for sensitivity to antibiotics, antagonism to fungi, production of auxins, ability to fix Nitrogen (presence of the nif gene), ACC deaminase activity and promotion of plant growth. Thus, the present project aims to: (1) isolate bacteria from the rhochosphere of Urochloa brizantha cultivated in sandy soils; (2) to characterize the isolated biochemical attributes related to the promotion of plant growth relating to each management system; (3) to analyze the nitrogen fixation ability by detecting the nif H region and (4) to evaluate the relationship between the biochemical characteristics of the isolates and the promotion of brachiaria growth. The results found will serve to generate information on diversity and growth promotion of plants in Bacillus sp present in pastures in integrated systems conducted in sandy soils.
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