Characterization of influenza A virus with nine segments: effect gene segment on virus property.

The influenza A virus genome consists of eight segments of negative-strand RNA. In previous study, we generated a recombinant influenza virus with nine segments by reverse genetics. In present study, we evaluated characteristics of the recombinant influenza virus. The recombinant virus exhibited similar property to wild-type virus on virion morphology, virion composition, plaque phenotype and other aspects. Whereas, the recombinant virus propagated to lower titers than did wild-type virus in cells and mice, and there was decreased protein level and vRNA incorporation in the recombinant virions compared to wild-type H9N2 virions. Our results indicated that influenza A virus with eight segments exhibits more advantages than the virus with nine segments.