Identification of 23 specific nucleotide patterns in the HN gene of Newcastle disease viruses isolated from Iran

Authors: MAJID ESMAELIZAD, Mehdi P. Ashtiani, SABER JELOKHANI NIARAKI, Khadije Hashemnejad

Abstract: Newcastle disease is considered the most contagious poultry disease and may cause severe economic loss in the poultry industry. The present study was undertaken to focus on molecular and phylogenetic analyses of the hemagglutinin-neuraminidase (HN) gene in the Iranian isolates. The nucleotide sequence of the HN (780-903 nt) coding region of 6 Newcastle disease viruses (NDVs), isolated from various outbreaks in Iran, was determined and aligned with previously published sequences of 26 NDV isolates in GenBank; the resulting alignment was then analyzed in terms of genetic variation. The number of nucleotide sequence variations presented by each of the isolates indicated that all 6 Iranian isolates contained 23 single nucleotide polymorphisms in the HN coding region. These polymorphisms can be considered signature nucleotides in this lineage. Specific positions are as follow: T795->C, T918->C, T1230->C, T1269->C, A819->G, A990->G, A1041->G, A1293->G, A1523->G, C834->T, C1299->T, C1383->T, C1386->T, C1545->T, C1560->T, G906->T, G1134->A, G1368->A, G1251->C, C1266->A, T1344->G, A1374->T, and T1401->A. Sequence analysis of the isolates showed that the 6 Iranian isolates examined share significant similarity with 2 Russian isolates, Sterna-Astr/2755/2001 and VOL95. Interestingly, both Russian isolates have the same nucleotide pattern as the Iranian isolates in all 23 nucleotide positions, except for isolate Sterna-Astr/2755/2001, which is only different at position 1560. The results may reflect that certain migratory birds, such as Sterna albifrons Pallas, might have contributed to the distribution of NDV in Russia and Iran. These best-known migratory birds travelling between Iran and Russia play a crucial role in the transmission of NDV.

Keywords: RT-PCR, Newcastle disease virus, hemagglutinin-neuraminidase, single nucleotide polymorphism, Iran

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