Establishment of a reverse genetics system for avian rotavirus A strain PO-13

Avian rotavirus A (RVA) is one of major enteric pathogens that cause diarrhoea in young avian individuals. Importantly, some of the avian RVA strains of G18P[17] genotype are naturally transmitted to and cause clinical diseases in mammalian species, indicating their potential risks to animal health. Although molecular information on the pathogenesis by avian RVA strains will be useful for estimating their risks, the absence of a reverse genetics (RG) system for these strains has hindered the elucida-tion of their pathogenic mechanisms. In this study, we aimed to establish an RG system for the avian G18P[17] prototype strain PO -13, which was isolated from a pigeon in Japan in 1983 and was experimentally shown to be pathogenic in suckling mice. Transfection with plasmids expressing 11 genomic RNA segments of the strain resulted in rescue of the infectious virus with an artificially introduced genetic marker on its genome, indicating that an RG system for the PO -13 strain was successfully established. The rescued recombinant strain rPO- 13 had biological properties almost identical to those of its wild -type strain (wtPO- 13). Notably, both rPO- 13 and wtPO- 13 induced diarrhoea in suckling mice with similar efficiencies. It was thus demon-strated that the RG system will be useful for elucidating the pathogenic mechanisms of the PO -13 strain at the molecular level. This is the first report of the establishment of an RG system for an avian RVA strain.