VP5 Gene Based Molecular Comparison of Indian and Global Isolates of Bluetongue Virus 2

摘要

Bluetongue virus (BTV) is a prototype species of the genus Orbivirus within family Reoviridae which causes bluetongue (BT) disease in domestic as well as wild ruminants. BTV is non–enveloped virus having 10 segmented dsRNA genome. Segment 6 encodes VP5 protein which along with VP2 protein gives serotype specificity to the virus. The BT2 isolate (Accession number JF899598) was grown in BHK 21 cell culture. The viral dsRNA was extracted from cell culture material. A pair of vp5 gene specific primer (Forward primer 288–307 bp and reverse primer 738–757 bp) giving an amplicon size of 470bp was designed using vp5 gene sequences available in GenBank database. The primer pair specifically amplified the desired region of template. The BT2 isolate showed maximum nucleotides (99.5–99.7%) as well as deduced amino acids (98.7–99.3%) sequence identity with South African, USA and most of the Indian isolates of BTV2 serotype. The sequence identity with European, Sudanese and Nigerian isolates was 85.7–87.2% for nucleotides and 94.2–95.5% for deduced amino acids. However, it showed 76.8–77.8% nucleotide and 87.1–87.8% deduced amino acid identity with eastern isolates. Results indicated the western origin of BT2 isolate (Accession number JF899598). Moreover, phylogenetic analysis also revealed the close relationship of BT2 isolate with Western BTV2 isolates. In–silico restriction enzyme analysis revealed that isolate in study can be differentiated from other BTV2 isolates from India, USA, South Africa, Europe, Australia and Japan using HindII, AarI, AcyI, AflIII, BsmAI restriction enzyme