Molecular diagnosis of the causal agents of bacterial canker on sweet cherry and biological approaches to their control

Bacterial canker and gummosis disease were caused by Pseudomonas syringae pv. syringae (Pss) and Pseudomonas syringae pv. morsprunorum (Psm race-1/Psm race-2) results to yield and crop loses significantly on the sweet cherry cultivation areas in our country. In this thesis, pathogen bacteria were isolated from the diseased samples taken from plants showing bacterial cancer symptoms in sweet cherry cultivation areas in Izmir and it's all around. Identifications of the pathogen isolates were performed by classical methods such as LOPAT (Levan production, Oxidase, Pectinolytic activity, Arginine dihydrolase, hypersensitivity on Tobacco), GATTa (Gelatine hydrolysis, Aesculin hydrolysis, Tyrosinase activity, Tartrate utilization) tests and classic-PCR method which were used primer sets designed to gene regions responsible from toxine production [syringomycin (SyrB), coronatine (cfl) and yersiniabactin (irp1)] to discriminate for pathogen bacteria. Biocontrol studies against the identified pathogens were carried out using bacteriophages and beneficial bacteria (BB) under growth chamber conditions. Out of eleven pathogenic bacteria were isolated from 44 infected plant samples taken from cherry orchards showing bacterial canker symptoms. As a result of diagnostic tests, 10 of the isolates were identified as Pss. In plant growth chamber studies with BB and bacteriophages on micropropagated sweet cherry seedlings, disease severity was detected on the control plants inoculated with Pss as 48.1 %. Ten days after patogen inoculation, 30 % of BB treatments and 66 % of bacteriophage treatments reduced disease severity more than 50 % with respect to that of positive control.