Incidence, distribution and characterization of Pseudomonas savastanoi pv. Savastanoi in Syria and identification of tolerant-resistant olive varieties
Field surveys were carried out in the main Syrian olive growing regions to estimate the severity and incidence of the olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi. The highest disease incidence (68%) was recorded in the Coastal region, while the lowest (10%) in the South. Based on morphological, biochemical, and pathogenicity tests as well as on iaaL and ptz gene amplifications, we established that 105 bacterial isolates obtained from the disease samples belonged to P. savastanoi pv. savastanoi. When an arbitrary 92% similarity cut-off level was considered, cluster analysis revealed that 60 out of the 69 selected isolates submitted to ERIC-PCR were present in a big cluster, which included the reference strains LMG 2209T, CFBP 6012 and CFBP 6013. The other 9 strains did not cluster with the outlier Pseudomonad strains included in the fingerprinting.
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Among the 14 major commercial olive cultivars used in Syria and tested in open-field experiments, Sourani was tolerant, while Al-Dou.aybli was the most susceptible one to two Syrian isolates of the pathogen.
