جداسازی و شناسایی عوامل شانکر باکتریایی درختان هسته‌دار در شهرستان اصفهان

Bacterial canker of stone fruits is one of the most destructive diseases of these plants. Different bacteria have been introduced as the cause of canker disease. The present research aimed to identify and investigate the pathogenicity and phenotypic characteristics of the bacterium (or bacteria) producing canker of stone fruits in Isfahan county. Stone fruit trees, including cherry, apricot, plum, cherry plum and peach, were visited in some areas of this region and tissues with canker symptoms were sampled. Bacterial isolation and purification was conducted and 137 isolates were obtained. The phenotypic tests including gram, oxidative/fermentative metabolism of glucose, catalase, fluorescent pigment production on King’s B medium, levan production, oxidase, potato rot, hypersensitive reaction on geranium and pathogenicity test on some stone fruits were performed. Finally, 33 isolates were selected and subjected to further phenotypic and genetic tests. Polymerase chain reaction with primer pair D21/D22 was conducted on them. Based on the investigated phenotypic characteristics, including LOPAT (Levan production, Oxidase production, Potato rot, Arginine dehydrolase and Hypersensitivity reaction) and GATTa (Gelatin liquefaction, Aesculin hydrolysis, Tyrosinase activity, and utilization of Tartrate) tests, some of the isolates were identified as Pseudomonas syringae pv. syringae (Pss) and some were identified as P. viridiflava. In the case of some isolates, no perfect match was found with Pss or P. viridiflava and additional tests are required to identify them.