Characterization of Causal Agents of Bacterial Spot on Tomato Fields in Iğdır Plain (Turkey)

Bacterial spot of tomatoes, a serious disease, significantly reduces tomato yields in Turkey and many other countries. In Iğdır Plain, this study was aimed to characterize bacteria that are causal agents of spot disease in tomatoes. Symptomatic tomato plants were collected from fields within the plain for bacterial isolation. Ten bacterial strains belonging to the genus Xanthomonas were isolated from different parts (leaves and fruits) of tomato plants. Through a series of analyses encompassing pathogenicity assessments, biochemical assays, FAME profiling, PCR using species-specific primers, and phylogenetic analysis of HrpB gene sequences, the strains were conclusively identified as Xanthomonas euvesicatoria pv. euvesicatoria and X. euvesicatoria pv. perforans. According to our results, FAME were not effective in distinguishing these two species (X. euvesicatoria pv. euvesicatoria and X. euvesicatoria pv. perforans). In addition, only the primer BS-XeF/BS-XeR detected X. euvesicatoria pv. euvesicatoria and other primers, i.e. Bs-XpF/Bs-XpR were not able to detect some bacterial strains. To our knowledge, while bacterial spot disease in previous studies was reported in Iğdır Plain, this study marks the pioneering identification of X. euvesicatoria pv. euvesicatoria and X. euvesicatoria pv. perforans as the precise causative agents of the disease in tomatoes cultivated in this area. Additionally, X. euvesicatoria pv. perforans strain XCV۲ was identified as the most virulent strain in this study. It caused a severity rate of ۷۴% in tomato (cv. 'Süper domates').

کلیدواژه ها:

Bacterial spot ، FAME ، HrpB gene ، Tomato ، Xanthomonas.