|LI, JIANGHONG - Non ARS Employee
|WANG, TINGYUN - Fujian Agriculture And Forest University
|ROSE, ROBYN - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center
|ZHAO, YAZHOU - Non ARS Employee
|LI, ZHIGUO - Non ARS Employee
|LI, JILIAN - Chinese Academy Of Agricultural Sciences
|HUANG, SHAOKANG - Fujian Agriculture And Forest University
|RODRIGUEZ-GARCIA, CRISTINA - Non ARS Employee
|BRISTER, RODNEY - National Institutes Of Health (NIH)
|CAO, LIANFEI - Non ARS Employee
|Chen, Yanping - Judy
Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2019
Publication Date: 1/14/2019
Citation: Li, J., Wang, T., Evans, J.D., Rose, R., Zhao, Y., Li, Z., Li, J., Huang, S., Heerman, M.C., Rodriguez-Garcia, C., Banmeke, O.A., Brister, R., Cao, L., Hamilton, M.C., Chen, Y. 2019. The phylogeny and pathogenesis of Sacbrood virus (SBV) infection in European honey bees, Apis mellifera. Viruses. 11(1):61. https://doi.org/10.3390/v11010061.
Interpretive Summary: Sacbrood is a contagious honey bee brood disease caused by Sacbrood virus (SBV). To date, there are no complete genome sequences of SBV strains originating from the U.S. available to the public. This study aims to fill the gap by providing novel sequences for addressing new emerging viral disease threats. Another important goal of this study was to investigate the effects of cold stress on SBV disease infection in honey bees. Results showed that cold stress could cause significant mortality in SBV infected larvae and suggests that high prevalence of sacbrood disease in early spring may be due to the long periods of cool damp weather observed during the season. Here we provide important insights into sacbrood disease epidemiology which can also help in the development of honey bee disease management strategies. The information obtained from this study should be of interest to researchers, graduate students, apiary inspectors, and beekeepers worldwide.
Technical Abstract: RNA viruses that contain single-stranded RNA genomes of positive sense make up the largest group of pathogens infecting honey bees. Sacbrood virus (SBV) is one of the most widely distributed honey bee viruses and infects the larvae of honey bees, resulting in failure to pupate and death. Among all the viruses infecting honey bees, SBV has evolved the greatest number of strains and lineages circulating in honey bee populations around the world; posing a risk for the emergence of new variants that may result in outbreaks of disease. In this study, we present the first report of whole genome sequences of two U.S. strains of SBV. The complete genome sequences of the two U.S. SBV strains were deposited in GenBank under accession numbers: MG545286.1 and MG545287.1. Both SBV strains show the typical genomic features of the Iflaviridae family. Phylogenetic, tree based, analysis of the single polyprotein coding region of the U.S. strains, and other GenBank SBV submissions isolated from the European honey bee Apis mellifera worldwide and the Asian honey bee A. cerana from southern Asia revealed that SBV strains split into two distinct lineages reflecting host affiliation. The phylogenetic analysis based on the 5'UTR revealed a monophyletic clade with the deep parts of the tree occupied by SBV strains from A. cerane, and the tips of branches of the tree occupied by SBV strains from A. mellifera, suggesting that strong immune responses to SBV infection in A. mellifera may drive rapid evolutionary changes in the virus. Further study to determine the effects of cold challenge on SBV infection showed that cold stress could have profound effects on sacbrood disease severity and outcomes manifested by increased mortality of infected larvae. This result suggests that high prevalence of sacbrood disease in early spring may be due to the fluctuating temperatures during the season. This study will contribute to a better understanding of the evolution and pathogenesis of SBV infection in honey bees, and have an important epidemiological relevance.