Identification of an additional N-glycosylation site and thermostable mutations within the hemagglutinin-neuraminidase gene of the Newcastle disease virus belonging to the VII.۱.۱ sub-genotype

Newcastle disease virus (NDV) is considered one of the most devastating avian viral patho-gens affecting the avian population, and it causes a significant economic burden on the poultry industry worldwide. The study aimed to gain deeper understanding of the molecular and phylogenetic analyses of the complete hemagglutinin-neuraminidase (HN) coding region among NDV isolates. The samples were obtained from different parts of Iran from July ۲۰۱۷ to February ۲۰۲۰, were used for phylogenic analysis in this study. The results confirmed the predominance of sub-genotype VII.۱.۱, previously known as sub-genotype VIIL, which is circulating in commercial broiler farms of Iran. Identification of (a) an additional N-glycosylation site (NIS) at position ۱۴۴; (b) mutations S۳۱۵P and I۳۶۹V which are related to increasing the viral thermostability; (C) cysteine residues at positions ۱۲۳; (d) amino acid substitutions in the HN antigenic sites, especially the mutations I۵۱۴V and E۳۴۷Q, as well as the other mutant within HN binding sites of the VII.۱.۱ sub-genotype, suggests the idea that this new sub-genotype of NDV may possess a high level of pathogenicity and virulence compared to other NDV sub-genotypes. In conclusion, the results indicate the presence of an additional NIS at position ۱۴۴, which may alter the virulence of the isolates. Furthermore, the presence of the thermostable mutations (S۳۱۵P and I۳۶۹V) and the other amino acid substitutions among the VII.۱.۱ sub-genotype isolates may have an impact on the vaccine immunity against this new NDV sub-genotype.

کلیدواژه ها:

Amino acid substitutions ، Hemagglutinin-Neuraminidase ، Newcastle disease virus ، phylogenetic analyses