Vp5 Gene Based Molecular Characterization of Bluetongue Virus 9 from South India

摘要

Bluetongue virus (BTV) is a prototype species of the genus Orbivirus within the family Reoviridae that causes Bluetongue disease (BT) in domestic as well as wild ruminants. The BTV isolate Ong5/06/Ind was isolated from sheep in Andhra Pradesh state in 2006. The isolate was confirmed as BTV based on characteristics CPE in BHK21 cell culture, 3:3:3:1 migration pattern of viral nucleic acid in RNA–PAGE and 366bp amplicon with group specific ns1 gene based PCR. VP5 gene based serotype specific primer produced specific PCR amplicon of 823bp corresponding to BTV serotype 9. Nucleotide sequence analysis revealed 97% identity with other Indian and European BTV–9 isolates, more than 90% with Asian and, only 68.8% with South African isolates. However, based on deduced amino acids, the identity was more than 97% with Indian, Asian and European and, only 73.4% with South African BTV–9 isolates. The in–silico restriction enzyme analysis (REA) with AflIII, BtrI and HindII showed a common pattern of restriction sites in Indian and European isolates at 1152, 1153 and 591, respectively. The lack of any of these restriction sites in African and other Asian isolates revealed the European origin of the study isolate. Similarly, the lack of BsmAI restriction site in Ong5/06/Ind isolate (Accession no. JF969307), differentiate it from European, Asian and South Africa isolates. The sequence analysis revealed that Ong5/06/Ind, Asian and European BTV–9 isolates were placed in nucleotype ‘C’ while South African isolates were placed in nucleotype ‘B’.