A pathogenic picorna-like virus from the endoparasitoid wasp, Pteromalus puparum: initial discovery and partial genomic characterization.

Using electron microscopy, we demonstrated the presence of a novel small RNA-containing virus in the venom apparatus of an endoparasitic wasp, Pteromalus puparum, designated as PpSRV. Morphologically, PpSRV has classical features of picorna-like viruses. It caused the development deterioration and tissue destruction of P. puparum venom apparatus. The laboratory colony of P. puparum was infectious with PpSRV at a low level. Partial genomic sequence analysis indicated that PpSRV 3'-proximal genome was characteristically similar to most dicistroviruses containing an internal ribosome entry site (IRES) for facilitating cap-independent translation and a 3' ORF encoding a structural protein with three major capsid polyproteins (28, 31 and 28 kDa) and a minor one (9.6 kDa). Phylogenetic evolution analysis of PpSRV structural protein with the counterparts of other dicistroviruses exhibited that PpSRV belonged to the Cripavirus genus and fell into same clade with Black queen cell virus (BQCV), an infectious virus to honey bee, suggesting that PpSRV might be pathogenic to P. puparum.