Whole-genomic analysis of a human G1P[9] rotavirus strain reveals intergenogroup-reassortment events.

Group A rotavirus (RVA) strain K8 (RVA/Human-tc/JPN/K8/1977/G1P[9]) was found to have Wa-like VP7 and NSP1 genes and AU-1-like VP4 and NSP5 genes. To determine the exact origin and overall genetic makeup of this unusual RVA strain, the remaining genes (VP1-VP3, VP6 and NSP2-NSP4) of K8 were analysed in this study. Strain K8 exhibited a G1-P[9]-I1-R3-C3-M3-A1-N1-T3-E3-H3 genotype constellation, not reported previously. The VP6 and NSP2 genes of strain K8 were related closely to those of common human Wa-like G1P[8] and/or G3P[8] strains, whilst its VP1-VP3, NSP3 and NSP4 genes were related more closely to those of AU-1-like RVAs and/or AU-1-like genes of multi-reassortant strains than to those of other RVAs. Therefore, strain K8 might have originated from intergenogroup-reassortment events involving acquisition of four Wa-like genes, possibly from G1P[8] RVAs, by an AU-1-like P[9] strain. Whole-genomic analysis of strain K8 has provided important insights into the complex genetic diversity of RVAs.