[Isolation and Identification of a Novel Cypovirus from Daphnis nerii].

Abstract

In order to develop a novel effective biological insecticide for controlling oleander hawk moth, a new pathogen was isolated from naturally diseased Daphnis nerii. Based on scanning electron microscopy, full-length amplification of cDNAs (FLAC), and phylogenetic analysis of genome segments 2and 10,the virus was identified as a new type of cypovirus (Da phnis nerii cypovirus [DnCPV]). Electrophoresis analysis showed that DnCPV had a genome comprising 10double-stranded RNA (dsRNA) segments, ranging from 892 to 4160bp.Using FLAC, the cDNAs from the 10 dsRNA segments of the new CPV were cloned and genome segments 2and 10 were sequenced. Sequencing results showed that segment 2 encoded RNA-dependent-RNA-polymerases (RdRps) and segment 10 encoded polyhedrin. These two segments shared conserved terminal sequences of AGUCAAA and AGC at the 5’and 3’ends,respectively.These conserved terminal sequences were not consistent with any of the known CPV types.Phylogenetic analysis of the RdRp and polyhedrin indicated that this CPV was more closely related to CPV type 19 and type 5than other CPV types. Based on the unique conserved terminal sequences and the electrophoresis pattern of the new virus, we tentatively named it DnCPV Nanchang isolate: DnCPV-NC.