Mummadireddy Ramya

Phylogenetic analysis of black queen cell virus genotypes in South Korea.

The black queen cell virus (BQCV), a picorna-like honeybee virus, was first isolated from queen larvae and pupae of honeybees found dead in their cells. BQCV is the most common cause of death in queen larvae. Phylogenetic analysis of two Apis cerana and three Apis mellifera BQCV genotypes collected from honeybee colonies in different regions of South Korea, central European BQCV genotypes, and a South African BQCV reference genotype was performed on a partial helicase enzyme coding region (ORF1) and a partial structural polypeptide coding region (ORF2). The phylogeny based on the ORF2 region showed clustering of all the Korean genotypes corresponding to their geographic origin, with the exception of Korean Am str3 which showed more similarity to the central European and the South African reference genotype. However, the ORF1-based tree exhibited a different distribution of the Korean strains, in which A. cerana isolates formed one cluster and all A. mellifera isolates formed a separate cluster. The RT-PCR assay described in this study is a sensitive and reliable method for the detection and classification of BQCV strains from various regions of Korea. BQCV infection is present in both A. cerana and A. mellifera colonies. With this in mind, the present study examined the transmission of honeybee BQCV infections between A. cerana and A. mellifera.

Analysis of the nonstructural and structural polyprotein regions, and complete genome sequences of Israel acute paralysis viruses identified from honeybees (Apis mellifera) in Korea

Phylogenetic trees were constructed for 24 partial nucleotide sequences of the nonstructural polyprotein (ORF1) and structural polyprotein regions (ORF2) of Korean IAPV genotypes, as well as eight previously reported IAPV sequences from various countries. Most of the Korean genotypes formed a distinct cluster, separate from other country genotypes. To investigate this phenomenon in more detail, three complete IAPV genome sequences were identified from different regions in Korea, i.e., Korea1, Korea2, and Korea3. These sequences were aligned with eight previously reported complete genome sequences and various genome regions were compared. The Korean IAPVs were very similar to those from China and Israel, but highly diverged from USA and Australian genotypes. Interestingly, they showed greater variability than the USA and Australian genotypes in ORF1, but highly similar to the Australian genotype in the ORF2 region. Thus, genetic recombination may account for the spatial distance between the Korean IAPV genotypes and those from other countries.

Comparative Genomic Analysis for Genetic Variation in Sacbrood Virus of Apis cerana and Apis mellifera Honeybees From Different Regions of Vietnam

Abstract Sacbrood virus (SBV) is one of the most common viral infections of honeybees. The entire genome sequence for nine SBV infecting honeybees, Apis cerana and Apis mellifera, in Vietnam, namely AcSBV-Viet1, AcSBV-Viet2, AcSBV-Viet3, AmSBV-Viet4, AcSBV-Viet5, AmSBV-Viet6, AcSBV-Viet7, AcSBV-Viet8, and AcSBV-Viet9, was determined. These sequences were aligned with seven previously reported complete genome sequences of SBV from other countries, and various genomic regions were compared. The Vietnamese SBVs (VN-SBVs) shared 91–99% identity with each other, and shared 89–94% identity with strains from other countries. The open reading frames (ORFs) of the VN-SBV genomes differed greatly from those of SBVs from other countries, especially in their VP1 sequences. The AmSBV-Viet6 and AcSBV-Viet9 genome encodes 17 more amino acids within this region than the other VN-SBVs. In a phylogenetic analysis, the strains AmSBV-Viet4, AcSBV-Viet2, and AcSBV-Viet3 were clustered in group with AmSBV-UK, AmSBV-Kor21, and AmSBV-Kor19 strains. Whereas, the strains AmSBV-Viet6 and AcSBV-Viet7 clustered separately with the AcSBV strains from Korea and AcSBV-VietSBM2. And the strains AcSBV-Viet8, AcSBV-Viet1, AcSBV-Viet5, and AcSBV-Viet9 clustered with the AcSBV-India, AcSBV-Kor and AcSBV-VietSBM2. In a Simplot graph, the VN-SBVs diverged stronger in their ORF regions than in their 5′ or 3′ untranslated regions. The VN-SBVs possess genetic characteristics which are more similar to the Asian AcSBV strains than to AmSBV-UK strain. Taken together, our data indicate that host specificity, geographic distance, and viral cross-infections between different bee species may explain the genetic diversity among the VN-SBVs in A. cerana and A. mellifera and other SBV strains.