Isolation of bacteriophages specific for Xanthomonas campestris pv. campestris and biocontrol of black rot disease of cabbage

Abstract

Twenty-one isolates of bacteriophages specific to eleven target strains ofXanthomonas campestris pv. campestris were isolated from soil samples collected under black rot-infected cabbage plants. An electron microscopic study of bacteriophage morphology allowed to classify 3 isolates as members of the Siphoviridae family, and the remaining eighteen isolates as those representing the Myoviridae family. After the analysis of phagotyping for seventy-three phytopathogen strains against newly isolated isolates and four collection strains of bacteriophages, it was proposed to construct a phage cocktail including isolates BT2, SM10, Ph30-1, Ph44, DB1 and Tir2, with combined infectivity of 88% strains of the X. campestris pv. campestris collection, representative for the Russian population of the pathogen. Treatment of cabbage seeds of cv. “Moscow late 15” with 25.6% seeds naturally contaminated with thepatho-gen with the cocktail of 5 bacteriophages resulted in a significant decrease of the black rot infection of seedlings. The estimated biological efficacy of the bacteriophage cocktail reached 90.6%.