A new genotype of the Sacbrood virus in honeybee Apis mellifera

Abstract

The sacbrood virus (SBV) causes the death of honeybee larvae. Until recently, three SBV genotypes were known: European, Asian, and South African [7, 9]. Serological assay, sequencing, and phylogenetic analysis of the SBV RNA polymerase gene fragment have revealed two genotypes of SBV circulating among honeybee Apis mellifera in the European region of the Russian Federation (RF); one of them forms an independent, not previously described genetic lineage (genotype 4), which occupies an intermediate position on the phylogenetic tree between the Asian and the South African virus genotypes. The strain 202/8 isolated in 2006 in Moscow oblast from honeybees previously imported from Uzbekistan and two variants (Tr5 and 6/A3) of the laboratory strain isolated in Kaluga oblast in 1986 belong to this group of viruses. The homology between them is 94.2%, while that with representatives of other groups does not exceed 80.6–83.5%. Another group of SBVs comprise European genotype viruses circulating in Stavropol krai, Adygea, and Moscow oblast (isolates 207/4 and 212/3). The homology between them is 99%. The two SBV genotypes found in the RF were differentiated by PCR and RID (radial immunodiffusion test). As for RID, both genotypes react with antiserum no. 6(1), but only the fourth genotype reacts with antiserum no. 58.