identification and determination of distribution of potato virus a in northern and razavi khorasan provinces using serological and molecular methods

abstract potato virus a (pva) is one of the members of genus potyvirus. pva particles are straight to slightly flexuous rods and contain of single stranded rna. in the spring and summer of 2005, sampling accomplished to determine potato virus a from potato fields in northern and razavi khorasan provinces. samples with mosaic, shining and rolling of leaves carried in ice chamber to laboratory for identification and further studies. some tubers were also collected. after tubers passed dormancy period at 4ºc they were transferred to laboratory to germinate. to detect pva in collected samples, bioassays, serological and molecular methods such as elisa and rt-pcr were used. total rna was extracted from infected samples by using peg6000 precipitation method and cdna was constructed. pcr was performed with specific primers from coat protein region. after electrophoresis on 1.5% agarose, the band of 1100 bp was detected. this amplified region was specific for cp pva. host range study of the virus was investigated in greenhouse on three species of host plant. to investigate distribution of the virus, the samples were collected randomly from potato fields located at mashhad, chenaran, shirvan, ghoochan, faroodje, bojnourd, fariman, kashmar, esfarayen, neishabour, torbat jam and torbat-e- heydariyeh and tested by das-elisa method. fields of kashmar were infected with pva in different proportions but no infections were observed in other tested fields of the region. this is the first report from existence of pva in northern and razavi khorasan provinces