Isolation and Characterization of Two Phages Infecting Streptomyces scabies

Potato scab is an important wide spread disease caused by Streptomyces scabies. Actinophages affect the composition and diversity of bacterial population, thereby, can be used as biological control. Two specific phages against S. scabies were isolated from different potato fields in different locations in Giza, Egypt. Phages were partially characterized using electron microscopy and genome structure. The first phage is suggested to belong to family podoviridae and was named vB_StscP-G1 however, the second phage belongs to family siphoviridae and was named vB_StscS-G2. Physical properties including dilution end point, longevity invitro, thermal inactivation point and host range were studied for the two isolated phages. Both phages were thermostable and were not affected by storage up to 180 days at room temperature. Furthermore, they were infective in acidic and alkaline conditions but, were totally inhibited at high alkaline conditions. Antiviral activity was also studied using different plant extracts and chemicals. Some plant extract showed a significant inhibitory effect on the isolated phages. However, sodium chloride and copper sulphate showed significant increase in the activity of the phages. Our results provide a useful data for designing a control strategy against potato scab disease.