Isolation and characterization of Israeli acute paralysis virus, a dicistrovirus affecting honeybees in Israel: evidence for diversity due to intra- and inter-species recombination.

We report the isolation, purification, genome-sequencing and characterization of a picorna-like virus from dead bees in Israel. Sequence analysis indicated that IAPV (Israeli acute paralysis virus) is a distinct dicistrovirus. It is most homologous to Kashmir bee virus and acute bee paralysis virus. The virus carries a 9487 nt RNA genome in positive orientation, with two open reading frames separated by an intergenic region, and its coat comprises four major proteins, the sizes of which suggest alternate processing of the polyprotein. IAPV virions also carry shorter, defective-interfering (DI)-like RNAs. Some of these RNAs are recombinants of different segments of IAPV RNA, some are recombinants of IAPV RNA and RNA from another dicistrovirus, and yet others are recombinants of IAPV and non-viral RNAs. In several of the DI-like RNAs, a sense-oriented fragment has recombined with its complement, forming hairpins and stem-loop structures. In previous reports, we have shown that potyviral and IAPV sequences are integrated into the genome of their respective hosts. The dynamics of information exchange between virus and host and the possible resistance-engendering mechanisms are discussed.