Classical and molecular diagnostic of Xanthomonad species causing bacterial spot on tomato and pepper

Bacterial spot on tomato and pepper caused by Xanthomonas species has been significant problem for tomato and pepper cultivation in Turkey. It was known unique Xanthomonas species which was named X. campestris pv. vesicatoria as causal agent of bacterial spot on tomato and pepper up to 1990s. According to the recent developments on bacterial taxanomy, there are four Xanthomonas species as causal agent of bacterial spot on tomato and pepper: X. vesicatoria (Xv), X. euvesicatoria (Xe), X. perforans (Xp), and X. gardneri (Xg). However; these causal agents have not been yet updated in Turkey and many other countries according to new established classification protocol. In this thesis project; it was aimed for identification of the strains of Xanthomonas spp. from tomato and pepper by biochemical and molecular methods, investigation of the differences among these strains in terms of pathogenicity and symptomatologly on tomato and pepper cultivars, common cultivated, and determination of sensitivity levels of the strains against copper. According to biochemical and molecular test results, 8 of 10 Xanthomonas spp. were identified as Xe, whereas other two strains were identified as Xp based on biochemical tests. These Xanthomonas species have been recorded as first report for Turkey in regard to new classification rules. Tested isolates of Xe and Xp occured the typical disease symptoms on tested tomato and pepper cultivars, and all of the tested cultivars were determined as susceptible. Out of four bacterial strains were concluded as resistant to 100 µg/ml copper, while one isolate was resistant to 200 µg/ml copper.