Background According to the differences of antigen and genetic composition, canine coronavirus (CCoV) consists of two genotypes, CCoV-I and CCoV-II. Since 2004, CCoVs with point mutations or deletions of NSPs are contributing to the changes in tropism and virulence in dogs. Results In this study, we isolated a CCoV, designated HLJ-071, from a dead 5-week-old female Welsh Corgi with severe diarrhea and vomit. Sequence analysis suggested that HLJ-071 bearing a complete ORF3abc compared with classic CCoV isolates (1-71, K378 and S378). In addition, a variable region was located between S gene and ORF 3a gene, in which a deletion with 104 nts for HLJ-071 when compared with classic CCoV strains 1-71, S378 and K378. Phylogenetic analysis based on the S gene and complete sequences showed that HLJ-071 was closely related to FCoV II. Recombination analysis suggested that HLJ-071 originated from the recombination of FCoV 79-1683, FCoV DF2 and CCoV A76. Finally, according to cell tropism experiments, it suggested that HLJ-071 could replicate in canine macrophages/monocytes cells. Conclusion The present study involved the isolation and genetic characterization of a variant CCoV strain and spike protein and ORF3abc of CCoV might play a key role in viral tropism, which could affect the replication in monocyte/macrophage cells. It will provide essential information for further understanding the evolution in China. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-021-03073-8.
【저자키워드】 Recombination, cell tropism, transcription-regulating sequence, Canine coronavirus, 【초록키워드】 Evolution, coronavirus, Genetic, variant, diarrhea, Spike protein, Antigen, Replication, China, cells, female, Isolation, Deletion, canine, genotypes, information, virulence, S gene, Analysis, Point mutation, strain, supplementary material, sequence, dead, Affect, Complete, isolate, vomit, Result, involved, addition, replicate, changes in, in viral, suggested, contributing to, experiments, ORF 3a, Welsh Corgi, 【제목키워드】 coronavirus, China, canine,