Characterization of a Goose-Origin Avian Orthoreovirus with Interferon Suppression Activity.

The emergence of variant strains of Avian orthoreovirus (ARV) has caused substantial economic losses in the poultry industry worldwide, but the molecular features of goose-origin strains and viral transmission among different avian species remain poorly understood. Here, we describe a goose-origin avian orthoreovirus strain, SD0407, associated with growth retardation and joint swelling. Complete genome analysis identified ten double-stranded RNA segments. Sequence comparison indicated that SD0407 is closely related to previously reported duck-origin reovirus strains. Phylogenetic and recombination analyses showed that most segments clustered with duck-origin strains, indicating close genetic relatedness among waterfowl-origin orthoreoviruses. Sequence and structural analysis of the σC attachment protein revealed ten unique amino acid substitutions, including D250 within the DE-loop region involved in receptor-binding. Molecular docking suggested that σC interacts with the conserved AnxA2-S100A10 heterotetrameric receptor complex, providing a possible structural basis for receptor compatibility across avian species. Although SD0407 replicated efficiently in goose embryo fibroblasts, it did not induce expression of type I, II or III interferons. Transcriptome profiling revealed weak activation of innate immune signaling and downregulation of metabolic and cytoskeletal genes, consistent with effective suppression of antiviral responses. These findings demonstrate that SD0407 combines structural variability with immune evasion to enhance host adaptability and underscore the importance of sustained ARV surveillance in waterfowl populations.