Genomic and phylogenetic characterization of a bunya-like virus from the freshwater Chinese mitten crab Eriocheir sinensis.

Abstract

The freshwater Chinese mitten crab (Eriocheir sinensis), an indigenous crustacean in China, has been cultured for more than 30 years. It was reported that the bunya-like virus from Eriocheir sinensis (EsBV) was associated with the tremor disease (TD), which causes high mortality and has a serious impact on production. In this study, full-length genome sequences of EsBV were pursued using next generation sequencing; the genome of EsBV was found to be composed of 6.7kb L, 3.3kb M, and 0.8kb S segments, respectively. PCR detection based genomic sequences showed that the positive rate of EsBV reached 40% in crabs from farming ponds. EsBV had the highest similarity with the Wenling crustacean virus 9, an unassigned, negative sense ssRNA virus. EsBV clustered with the Wenling crustacean virus 9 firstly, and then the branch clustered with Peribunyaviridae clade in every phylogenetic tree - based on L, M and S encoded sequences, respectively, indicating that EsBV can be classified in the family Peribunyaviridae, to which the orthobunyaviruses belongs, but not belonging to any known genera in the family Peribunyaviridae. There were unique complimentary terminal sequences for EsBV, with only partial consensus with members from the orthobunyaviruses. We believe that the findings of this research will be vital for future research about EsBV and will also go a long way in illuminating its relationship with TD. Keywords: Eriocheir sinensis; tremor disease; bunyavirus; EsBV; genome sequences.