Biochemical and Molecular Characteristics of Pc1 Virulent Phage Isolate Infecting Pectobacterium carotovorum

Abstract

Background and Objective: Pectobacterium carotovorum subsp. carotovorum is a plant-pathogenic bacterium. It is a post-harvest pathogen and causes soft rot diseases in infected plants. Different virulent bacteriophages have been isolated from different regions in the world. These bacteriophages were tolerant to high concentrations of calcium chloride and magnesium chloride. Whereas, the high concentrations of zinc chloride and aluminum chloride decreased the activity and stability of phages. Therefore, the present research aimed to study the biology of P. carotovorum phage (Pc1) by using a one-step growth experiment, its stability to different concentrations of some chemicals and molecular characteristics of this phage isolate. Materials and Methods: One step growth experiment, chemical stability, and molecular characteristics by using RAPD-PCR of P. carotovorum phage (Pc1) were studied. Results: The P. carotovorum phage (Pc1) isolate was found to have a latent period of 20 min and its burst size is about 92 pfu cellG1 . Calcium chloride, magnesium chloride, and copper sulphate (from 0.1-0.5 mM) increased the infectivity of Pc1 phage, while, zinc chloride in the same concentrations reduced its infectivity. RAPD-PCR amplification was indicated that the total amplified products were 32 bands with size ranged from 0.179-2.365 Kbp. Conclusion: Since, zinc chloride (at concentrations of 0.1-0.5 mM) reduced infectivity of Pc1 phage isolate, therefore, any chemical compounds containing zinc must be avoided in designing biocontrol strategy by using phages against soft rot bacterium (P. carotovorum) in potatoes.