Location: Bee Research Laboratory
Project Number: 8042-21000-291-070-I
Project Type: Interagency Reimbursable Agreement
Start Date: Oct 1, 2022
End Date: Sep 30, 2023
Honey bee viruses have been frequently reported to be associated with poor colony health and bee losses. Sacbrood virus (SBV) is the most widely distributed of all the honey bee viruses and has evolved the greatest number of variant strains circulating in bee populations around the world. Recent studies showed that Apis cerana strain of SBV that causes devastating disease in Asian honey bees (Apis cerana) could cross host species barrier and cause infection in the European honey bee Apis mellifera, posing a significant risk for future honeybee emerging disease events. This collaborative project involves team members from the USDA- Agricultural Research Service (ARS) Beltsville Bee Research Laboratory (Drs. Yanping Chen and Jay Evans) and the USDA-Animal and Plant Health Inspection Service (APHIS), Plant Protection and Quarantine (PPQ) (Drs. Todd Gilligan, Allan H. Smith-Pardo). The research focuses on the Investigation of epidemiology and pathogenesis of SBV infection in different geographic regions to determine the significance of differences in genome sequence to the pathology of SBV in both A. mellifera and A. cerana. This information will then be used to design novel bee disease control strategies in response to emerging disease outbreaks, specifically, help to protect the USA homeland if A. cerana strains of SBV are ever introduced. The broad objective will be achieved by fulfilling the following specific research objectives: • Obj- 1. Characterize SBV infection kinetics, tissue tropisms, and histopathology in honeybees • Obj-2. Elucidate honeybee hosts’ responses to SBV invasion and uncover honeybees’ genetic susceptibility to the SBV infection • Obj- 3. Develop novel diagnostic tools and therapeutics for combating SBV and mitigating oxidative effects induced by SBV infection
For Obj-1, SBV-infected bees from different regions where A. mellifera or A. cerana, or both, are managed for pollination services will be collected and the genomic sequences of representative SBV-infected bees associated different host species, transmission, and disease severity will be analyzed to better understand how spatial ecology and virus evolution jointly shape epidemic dynamics of the disease. Based on the genomic information, PCR primers for detection of various genetic variants of SBV will developed for sensitive and rapid screening approaches. For Obj-2, The host transcriptional responses of honey bees to the SBV infection will be investigated using sing an RNA sequencing-based approach. The roles of host factors in virus infection, replication, and pathogenesis will be elucidated, thereby improving identification of potential drug targets. For Obj-3, The impacts of antiviral medicines including natural products, immune modulators, and dsRNA on the suppression of SBV replication will be evaluated by qRT-PCR method. The phenotypic impact of RNAi treatment on overall performance and health of honeybees will be also evaluated.