Detection And Molecular Characterization Of Isolates Of Potato Virus A In Hunan Province

Potato virus A (PVA), one of an important factor affecting the yield and quality of potato,is a member of the family Potyviridae, which can reduce the potato crop yield up to40%. But few studies have been carried out to characterize the virus and its diversity in the country, even blankly in Hunan province. The object of this study is to detect and identify PVA isolates in Hunan Province. The main results were shown as follow:1. The virions in the potato material collected from Xiangxi, Hunan were observed by the transmission electron microscopy, the virus particles were linear rod with750nm long and13nm wide approximately, and which can be judged as the potyviruses.2. The virus was identified to be PVA by distinguishing the phenotypic differences in inoculated Indicator plant(Physalis floridana, Nicotiana tabacum, the potato hybrid’A6’). And this PVA isolate from Hunan caused the similar symptom to the PVA isolate Her and U in the inoculated potato cv ’King Edward’.3. The virus was confirmed to be PVA by detection with DAS-ELISA.4.That the experimental material was infected with single PVA was further confir-med by multiplex RT-PCR, this results were consistent with that in the detection of electron microscopy, DAS-ELISA and indicator plants.5.The complete nucleotide sequence of PVA isolate Hunan was cloned and seque-nced.The complete nucleotide sequence, polyprotein amino acid sequences, CP gene nucleotide sequence and CP amino acid sequence of PVA isolate Hunan were compared with the reported PVA isolates in Genbank. The results showed that the identities of complete nucleotide sequence, amino acid sequences of polyprotein, nucleotide sequence of CP gene and amino acid sequence of CP of PVA isolate Hunan with other PVA isolates were84%-98%,93%-99%,89%-99%,and95%-100%respectively, there was no variation of the Aphid-transmissibility motif DAG in the PVA isolate Hunan.