Pepper races 7, 8 and 10 of Xanthomonas axonopodis pv. vesicatoria isolated from diseased pepper plants in Turkey

In the summer of 1999 and 2000, 21 strains of Xanthomonas axonopodis pv. vesicatoria (Xav) (Jones et al., 1998) were isolated from diseased pepper plants grown in 15 greenhouses and 6 commercial fields in the Mediterranean (Antalya) and eastern Anatolia (Erzurum, Erzincan and Yusufeli) regions of Turkey. The strains were characterised on the basis of physiological tests, analysis of whole cell fatty acids (FAME), indirect enzyme-linked immunosorbent assay (ELISA) and pathogenicity and hypersensitivity tests on pepper differential genotypes as previously described (Bouzar et al., 1994). None of the strains were pectolytic or amylolytic. FAME analysis showed that all strains had similar fatty acid profiles, and matched the strains to Xav with similarity indices ranging from 0.43 to 0.79. All strains reacted with a set of Xav-specific monoclonal antibodies Xv1, 5, 6 and 10, but not with MABs Xv8, 15 and 30 known to react positively with X. vesicatoria or/and X. gardneri, the other taxa besides Xav into which X. campestris pv. vesicatoria has been reclassified (Bouzar et al., 1994; Jones et al., 1998). They were all pathogenic on pepper (cv. Marengo) plants. The results of hypersensitivity tests performed on pepper differential lines that include Capsicum pubescens PI 235047, C. annuum cv. Early Calwonder (ECW) and its near-isogenic lines (designated ECW-10R, ECW-20R and ECW-30R) showed that 8, 2 and 11 of the strains belonged to Xav pepper races 7, 8 and 10, respectively (Kousik and Ritchie, 1999; Sahin and Miller, 1998). Since the race identity of X. axonopodis pv. vesicatoria strains causing bacterial spot disease on pepper in Turkey has not been determined before, this is the first report of the observation of Xav pepper races 7, 8 and 10.

This study was supported by a grant from the Research Funds appropriated to Atatürk University.