Copper-resistant strains of Xanthomonas axonopodis pv. vesicatoria (Doidge) Dye in the eastern Mediterranean region of Turkey

Abstract

Bacterial spot, caused by Xanthomonas axonopodis (syn: campestris) pv. vesicatoria is a widespread disease of processing pepper in Adana and Osmaniye (eastern Mediterranean Turkey). According to our and pepper growers' observations, chemical control by copper compounds has not been effective on the disease in commercial pepper fields for the last three years. Therefore, sensitivities to copper and streptomycin among strains were tested under in vitro conditions. In the summers of 2002-2004, sixty-seven bacterial strains were isolated from diseased pepper plants in the region. The strains were identified as Xanthomonas axonopodis pv. vesicatoria by morphological, physiological and biochemical tests, hypersensitive reaction on tobacco (Nicotiana tabacum cv. Samsun N), pathogenicity tests on pepper plants (a local cultivar, Bursa Yaglik), das-ELISA and amplification of the 355 bp hrp genes by PCR. Of the 67 strains, all were found to be tolerant to 100 mu g ml(-1) of cupper sulfate and 7 % were resistant to streptomycin (20 mu g ml(-1)).