Background and Objective:Bacillus megaterium is commonly used as a phosphate dissolving bio-fertilizer. Presence of bacteriophages
in the soil is likely to be the significant environmental agents effecting the protection and activities of such useful bacteria. Receptors play
a definitive role in the development of bacterial resistance to bacteriophage infection, the adsorption resistance divided to three groups:
Blocking of phage receptors, production of capsule layers and presence of competitive inhibitors. In this study efforts were made to
protect B. megaterium against its phage infection. B. megaterium was immobilized system with different concentrations of alginate.
Moreover, blocked phage adsorption receptors B. megaterium mutants resistant to phage infection were induced via exposure of
B. megaterium to U.V. irradiation at wave length of 240 nm for 20 min. Methodology: Different concentration of sodium alginate
(3, 5, 7 and 9 % w/v) and U.V. irradiation of 240 nm at distance of 60 cm from plates for 5, 10, 15..... up to 30 min were used for prepared
two different formula of B. megaterium (wild type) bacteria as a resistant to phage infection. Results: Bacillus megaterium isolate
efficient in dissolving phosphate and the isolate was non-lysogenic and susceptible to an isolate of lytic bacteriophage. Presence of phage
had no effect on immobilized cells of B. megaterium with 7% alginate immobilized and blocked phage adsorption receptors
B. megaterium mutant which obtained after 20 min. The blocked phage adsorption receptors B. megaterium was more efficient in
decreasing the pH value in its liquid culture than the other mutant after 25 min, therefore, this mutant was selected to be as a bio-fertilizer
inoculum. Under green house conditions fertilization of wheat plants inoculated with immobilized cells (7%) and blocked bacteriophage
adsorption receptors Bacillus megaterium mutant resistant to phage infection, no significant effect for presence of phages was discover,
as compared to those fertilized with the free cells in presence of bacteriophages. Conclusion: The results of this study showed that two
mechanisms (Immobilized system and blocked phage adsorption receptors system) can be used to protect B. megaterium from phage