Evaluation of bacteriophages in the biocontrol of Pseudomonas syringae pv. syringae isolated from cankers on sweet cherry (Prunus avium L.) in Turkey

Abstract

Abstract Background Bacterial canker and subsequent gummosis are caused by multiple pathogens and lead to significant yield and productivity losses in sweet cherry cultivation in Turkey. This study identified that Pseudomonas syringae pathovars were responsible for bacterial canker on sweet cherry orchards by using classical and molecular methods and evaluated the biocontrol effects of bacteriophages against P. syringae pv. syringae. Results Pathogenic bacteria were isolated from samples taken from plants showing symptoms of bacterial canker in cherry orchards located in İzmir and Manisa provinces. Specific pathogens were identified using pathogenicity, phenotypic tests, and simplex PCR. Bacteriophages effective against P. syringae strains were isolated from soil contaminated with pathogens identified in the diseased orchards using an optimized isolation protocol. The biocontrol activity of bacteriophage isolates against P. syringae pv. syringae was tested in vitro and in vivo. The results of pathogenicity tests on immature sweet cherry fruits and micropropagated cherry plantlets revealed 10 pathogenic bacteria isolates from 44 plant samples taken from sweet cherry orchards showing symptoms of bacterial canker. Conclusions Ten isolates were identified as Pseudomonas syringae pv. syringae. Nine different pure bacteriophage isolates were effective. The results indicated that bacteriophage isolates may demonstrate variable reactivity against P. syringae pathovars.