Characterization of the Full Length P and M Genes in a Newcastle Disease Virus Isolated from Chicken Farms in Northeast of Iran

Newcastle disease virus (NDV) is an avian pathogen that infects various birds worldwide. Recurrent outbreaks of ND consistently occurring in Iran cause substantial economic losses each year. The Northeast region of Iran has an extensive commercial poultry industry and is also a big exporter of poultry products to other countries. Therefore, consistent and dynamic surveillance of the NDV's prevalence in this geographic region is essential in controlling the disease.

The virulence of the virus is determined based on the sequence of Fusion (F) protein. However, though the Phosphoprotein (P) and Matrix (M) proteins of NDV are also involved in the evolution and pathogenicity of the virus, molecular evaluation of their genomic loci in the NDVs prevalent in Iran is limited. Here, we present data for the sequences of full-length P and M genes belonging to an NDV that caused the ND outbreak of 2011 in the Northeast of Iran.

The genomic sequences encoding full-length P and M proteins as well as that of F protein were amplified using PCR and sequenced by the Sanger sequencing. The obtained sequences, plus their translated proteins, were evalu-ated using various bioinformatics approaches, such as homology and phylogenetic analyses.

Phylogenetic analyses based on P, M, and F genes clustered our isolate together with VII.I.I GenBank se-quences from Iranian sources reported from 2011 to 2019, as well as with those reported from China. But our isolate showed less homology to vaccine strains commonly used in Iran.

Our study showed that, in addition to the newly evolving sub-genotypes, VII.1.1 variants are still circulating in the region. The weak homology in determinant regions between this strain and those used for vaccine pro-duction must be considered in vaccination programs. Further, the persistent presence of NDV genotypes already prevalent in the Far East in Iran highlights the importance of biosecurity management and dynamic surveillance in controlling ND.