Comparison of gene sequences of VP2 hypervariable region of field and vaccine strains of infectious bursal disease virus

Abstract

Infectious bursal disease virus (IBDV) isolated from different areas in and around Tamil Nadu were characterized by nested PCR technique. The purified amplicons were subjected to automated sequencing and phylogcnetic analysis was performed on the sequence generated by cycle sequencing comprising the variable region of the VP2 gene of 18 feild isolates. The Tamil Nadu IBDV isolates showed a divergence of 0.2 to 4.2% at the nucleotide level and 2.1% at amino acid level. Eleven nucleotide changes were consistent with specific amino acid changes. The serine rich heptapeptide sequence "SWSASGS" was conserved in all the isolates. All the isolates were closely related to the very virulent IBDV isolate LJK 661 of European origin. The sequences of 18 IBDV field isolates were submitted to the gene bank and allotted accession numbers AY 321518 to AY 321527, AY 327576-AY 327579 and AY 359862-AY 359865.