Study of phenotypic characteristics of potato bacterial wilt isolates in Fars and Hamedan provinces, Iran

In order to study of Phenotypic characteristics of potato bacterial wilt isolates, several potato fields were surveyed for potato wilt plants in Fars and Hamadan provinces of Iran during 000-00. The infected samples to potato wilt were collected and screened for bacterial infection under laboratory condition. Isolation and purification of suspected bacterial samples were done on TTC (,,5-triphenyl tetrazolium chloride) culture medium. Characteristics of bacterial isolates were determined on the basis of colony morphology, biochemical differentiations, pathogenicity and antibiotic sensitivity tests as well as whole cell protein analysis. In this study, a typical HR symptom was observed in infiltrated tobacco leaves after 4-48 hours. All isolates were assigned in race biovar, based on the pathogenicity tests on tomato and potato seedlings and utilization of defined carbohydrates by isolates. Utilization of glucose, sucrose and trehalose were positive for all isolates, whereas it was negative for ramnose, raffinose, arabinose, fucose and tartrate. HS production from cysteine, urease, oxidase, catalase and utilizing of sodium citrate were positive, while indole, methyl red, arginine dihydrolyase, gelatin and starch hydrolysis and utilizing of malonate and gluconate were negative. In bacterial cell membrane protein analysis using SDS-PAGE method, no significant differences were observed in electrophoretic patterns of local and standard strains (ACH 058 from Australia and CIP 0 from Peru) and only strain RsR79 was a little different from others.