Genetic Characterization of DH13M98, Umatilla Virus, Isolated from Culex tritaeniorhynchus Giles in Yunnan Province, China

Abstract

Background: In August 2013, a virus strain (DH13M98) was isolated from Culex tritaeniorhynchus Giles collected in Mangshi, the southwestern border area of Yunnan Province, China. The virus replicated and caused cytopathic effects (CPE) in Aedes albopictus (C6/36) cells, but not in baby hamster Syrian kidney (BHK-21) cells. Materials and Methods: Agarose gel electrophoresis (AGE) analysis revealed that the DH13M98 virus was a 10-segment double-stranded RNA (dsRNA) virus, with a "1-1-1-2-1-1-2-1" pattern. The full genome of the DH13M98 virus was sequenced by full-length amplification of complementary DNAs (FLAC). Results: Phylogenetic analysis of the viral RNA-dependent RNA polymerase (Pol), major subcore-shell (T2), and major core-surface (T13) protein showed that DH13M98 clustered with Umatilla virus (UMAV), and the amino acid (aa) sequences of DH13M98 shared more than 89.5% (Pol), 95% (T2), and 91.1% (T13) identity with UMAV. However, the aa identity of outer capsid protein one (OC1) of DH13M98 with other UMAV was 57.1-79.2%, suggesting that DH13M98 was UMAV, but distinct from other strains of UMAV from the United States, Japan, and Germany at OC1, and it may be a high variant strain of UMAV, even a new serotype. Conclusion: This is the first isolation of UMAV in China, which enriches the resources of virus species in China and provides new insights into the genetic diversity and geographical distribution of the virus.