Developing a New Method for Pathotyping of Newcastle Disease Virus Based on Sialidase Protein

Newcastle disease virus (NDV) is considered as a deadly infection to majority of the avian species. One of the key factors responsible for virus pathogenesis is sialidase protein expressed by hemagglutinin-neuraminidase gene on the envelope of virus particles, which involves in virus attachment to cells. In this study we compared restriction map of hemagglutinin-neuraminidase gene encoding sialidase protein among Lentogenic strains and Velogenic isolates obtained in Iran, and a variety of virus genotypes (I–VII) retrieved from GenBank. A polymorphic region with 527 bp length was found in the mentioned gene. Reverse transcription-Polymerase chain reaction was done for Iranian Velogenic isolates and vaccine strains (B1, La Sota and V4). The Pattern of four restriction endonuclease enzymes (AluI, AvaIl, HaeIII and TaqI) was analyzed by Polymerase chain reaction-Restriction fragment length polymorphism technique. There were significant differences among Iranian Velogenic isolates and vaccine strains. The experimental results of the mentioned method were in concordance with in silico evaluations of restriction map of 146 strains including: class I and class II genotypes obtained from the National Center for Biotechnology Information (NCBI). Therefore, we suggest that this method might be useful for pathotyping and differentiation of class I and II Newcastle disease virus.