Isolation and characterization of phages Stsc1 and Stsc3 infecting Streptomyces scabiei and their potential as biocontrol agents

Abstract

Phages infecting Streptomyces scabiei were isolated from 25 soil samples and their genomes analyzed by comparing the DNA fragment profile obtained from restriction enzyme digestions. Two genetically different phages infecting S. scabiei were found and were named Stsc1 and Stsc3. Phages Stsc1 and Stsc3 were found to have a binal symmetry with an icosahedral head and a long, striated tail based on observations using electron microscopy. Bacterial host ranges of Stsc1 and Stsc3 were tested: these phages infected 88% and 75% of the pathogenic S. scabiei strains tested, respectively. Infection of S. scabiei strains by phages Stsc1 and Stsc3 was evaluated on solid medium at pH 5.5–7.5 and at temperatures varying from 15 to 30 °C. The potential use of the phages as biocontrol agents against the pathogen was assessed on radish seedlings in vitro. Both phages prevented symptoms of S. scabiei on radish seedlings.

Keywords:

• bacteriophage
• Streptomyces scabiei
• common scab
• potato
• biocontrol