Evaluation and Identification of Potato Bacterial Disease in Khuzestan Province

In the present study , several bacterium isolates were isolated from infected tubers and stem of potato with soft rot , black leg and wiliting symptoms during 2001-2003 from different regions of khuzestan province . physiological , biological and pathogenecity testes were carried out on them.The obtained isolates from potato with soft rot and black leg symptoms were rod â€andldquoshaped , motile with peritrichous flagella , gram negative , facultative anaerobe , oxidase negative , catalase positive , and they were able to rotting potato tuber slices , but they were negative in hypersensitive reaction on tobacco . also the majority of the isolates produced acid from glucose, glycerol , arabinose , lactose , ribose , manitol , manose , xylose , froctose . all the isolates reduced nitrate and produced H2S from cystein and were identified as pectobacterium. On the basis of phenotypic analysis , these isolates establish in two group.First group were sensitive to erytromycin but could not produced indole and phosphatase and for the reason that produced acid from خ±-methyl-D-glucoseide and palatinose and redusing substance from sucrose but did not grow at 36-37 oc , there for were recognised as strains of pectobacterium carotovorum subsp atrosepticum.Second group grew at 36-37 oc but did not produce acid from خ±-methyl-D-glucoseide ,palatinose and also redusing substance from sucrose , therefor were identified as strains of pectobacterium carotovorum subsp carotovorum.other strains that obtained from potato with damping off and wilting symptoms were rod â€andldquoshaped ,non motile ,gram negativee .aerobic ,oxidase positive , catalase positive , they could not rot the potato slices and they were negative in hypersensitive reaction on tobbaco. They produced acid from lactose , maltose , cellobiose but could not able to produced acid from sorbitol , manitol and delesitole.theand starch and produced orease, phosphatase and could hydrolyse Tween 80, therefor identified as ralstonia solanacearum.se isolates did not poduced fluorescent pigment on King B medium and could not hydrolyse gellatin