identification of the causal agent of blackleg and soft rot of potato in ardabil province

in order to characterizeblackleg and soft rot agent of potatoin ardabil province, samples showing mentioned symptoms were gathered from fields and storages during 2012 and 53 pectolytic isolates were obtained in primary purification. after confirming their pathogenicity, phenotypic features were investigated and compared to those of the reference strains. rotting severityof isolates and infection percentage were determined in each region. based on differential phenotypic tests related to enterobacteriaceae, the high variation was shown among isolates and all testes strains divided to six groups. according to our data, isolates belonged to first and second group resembled pectobacteriumcarotovorum subsp. carotovorum and p.wasabiae, respectively. the third group was similar to p. atrosepticum and the fourth group formed a separate group with dickeyachrysanemi. these results were confirmed by molecular assays. some isolates related to fifth group showed intermediate features between pccand dch..the sixth groupwas included just one isolate and based on the phenotypic characteristics was similar to both pcc and pw.among sampling regions in ardabil, kalkhoran with 18.75 % infection, showed the hightest rate of contamination to pectolytic bacteria.