RESUMEN
<b>Background and Objective:</b> Phosphorus (P) is one of the most limiting nutrients for plant growth. Phosphorus deficiency is limiting crop production in many agricultural soils worldwide. The application of phosphorus solubilizing bacteria (PSB) to soils can replace or partially reduce using of inorganic P fertilizers. A bacteriophage, or phage, is a virus that infects a bacterial cell, taking over the host cell's genetic material. The four phages were propagated, purified, studied for the morphological properties, finally studying the genetic diversity. <b>Materials and Methods:</b> Obtained, examined the efficiency and identification of bacteria for solubilizing phosphorus. Isolation, studying the properties and studying genetic diversity. <b>Results:</b> Four virulent phages (Bv<sub>1</sub>, Bv<sub>2</sub>, Bv<sub>3</sub> and Bv<sub>4</sub>) specific for <i>Bacillus velezensis</i> were isolated from the Egyptian soil. The <i>Bacillus</i> phages were purified by alternative low and high-speed centrifugation methods. Electron micrographs showed that phages appeared to be a member of the <i>Siphoviridae </i>family based on their structure and particle morphology (the particles have a head and long non-contractile tail). Sodium Dodecyl Sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) technique was performed to determine the properties of viral proteins. It was found that the Bv<sub>1</sub> virus had five structural proteins, while Bv<sub>2</sub> and Bv<sub>3</sub> virus had eight structural proteins and finally, the Bv<sub>4</sub> virus had ten structural proteins. The purity and quantity of isolated DNAs were determined spectrophotometrically. Data showed that the concentration of Bv<sub>1</sub> DNA was 0.75 µg, Bv<sub>2</sub> DNA and Bv<sub>3</sub> DNA was 0.60 µg and finally Bv<sub>4</sub> DNA 0.55 µg µL<sup></sup><sup>1</sup>. The analysis of genetic material of <i>B. velezensis</i> phages was determined based on both the ISSR-PCR technique and the effect of restriction enzymes. Data showed different amplification patterns with all phages. <b>Conclusion:</b> The bacteriophages of <i>B. velezensis</i> were isolated from soil, propagated, purified, study some of its properties.