Biological Control of Pectobacterium carotovorum Via Specific Lytic Bacteriophage

Abstract

Background: Many bacteria cause post harvest diseases of different fruits and consequently quality and availability of these fruits could be affected. The pathogenic bacteria involved in this respect are species belonging to different genera such as Erwinia, Pseudomonas and Xanthomonas. Significant reduction in the disease caused by Pectobacterium carotovorum subsp. Carotovorum was achieved with application of PP1 phage. Generally, P. carotovorum subsp. Carotovorum controlled effectively by PP1 phage treatment. Aims: This investigation aims to possible use the lytic phage against Pectobacterium carotovorum as a biocontrol agent to avoid the soft rot disease under storage condition. Materials and Methods: Biological and Biochemical experiments were used to study different characterization of specific a lytic phage isolate and the usage of this phage as a biocontrol agent against Pectobacterium carotovorum. Results: A lytic bacteriophage specific to Pectobacterium carotovorum was isolated from a clay soil samples. This lytic phage was designated Pc1.The thermal inactivation point of the isolated phage was found to be 64°C and its longevity in vitro was 120 hrs. The phage isolate have a hexagonal head and long contractile tail. The isolated phage (Ec1) effectively controlled the soft rot diseases of potato tubers caused by P. carotovorum. The rot severity markedly reduced when the Ec1 phage was applied as phage suspension or as spray to the P. carotovorum infected tubers. Conclusion: The results of this investigation showed that a specific phage can be used as a bio-control agent against Pectobacterium carotovorum. The percentages of rot severity in tubers inoculated with the pathogenic bacteria plus phage suspension and those inoculated with bacteria plus phage spray were found to be 3.42 % and 2.62 %, respectively. The isolated phage (Pc1) effectively controlled the soft rot disease of potato tubers caused by Pectobacterium carotovorum. The rot severity markedly reduced when the Pc1 phage was applied as phage suspension or as spray to the Pectobacterium carotovorum infected tubers.