A Retrospective Phylogenetic Analysis of Matrix Gene and Amantadine Resistance in Avian Influenza (H9N2 subtype) During 2014-2015 in Isfahan, Iran

Influenza is a main viral disease in poultry production that causes various annual economic losses to the poultry production industry. Avian influenza virus (AIV) is susceptible to antigenic changes, and the genome of this virus codes different proteins some of which have more biological properties. The matrix (M) protein is one of these proteins that plays a role in the immunization and pathogenesis of the virus. Therefore, the evaluation of molecular characteristics and changes in the influenza gene can provide a new horizon for further genomic studies. Accordingly, in this study, the molecular characteristics of AI H9N2 strains were compared with those of other reference strains in the world gene bank by determining their M gene sequence.

In this regard, 4 strains of AIV (H9N2) were selected for the analysis of the M gene sequence. The polymerase chain reaction product was sequenced after its purification from the gel and the amplification of the M gene. Finally, the nucleotide sequence of these strains and other reference strains were aligned and analyzed by MegAlign software using the Clustal W method.

The results indicated that the M gene sequences of AIVs belonging to the last decade were highly similar to each other and other reference strains in special regions such as the ionic gate and the cleavage site. Based on the M sequence, 3 strains appeared to be resistant to amantadine. These viruses in the epitope regions showed a high similarity to the highly pathogenic avian influenza (HPAI) Hong Kong H5N1 strain.

In general, it seems that the sequence of the M gene in Iranian H9N2 strains belonging to the last decade is relatively constant although the continuous monitoring of changes in various genes of the influenza virus is necessary