The Dynamics of Deformed Wing Virus Concentration and Host Defensive Gene Expression after Varroa Mite Parasitism in Honey Bees, Apis mellifera

• Published in: Insects (Basel, Switzerland) Switzerland), 2019-01, Vol.10 (1), p.16
• Main Authors: Zhao, Yazhou, Heerman, Matthew, Peng, Wenjun, Evans, Jay D, Rose, Robyn, DeGrandi-Hoffman, Gloria, Simone-Finstrom, Michael, Li, Jianghong, Li, Zhiguo, Cook, Steven C, Su, Songkun, Rodríguez-García, Cristina, Banmeke, Olubukola, Hamilton, Michele, Chen, Yanping
• Format: Article
• Language: English
• Subjects: Animal behavior; anti-pathogen mechanisms; Apis mellifera; Asymptomatic; Beekeeping; Bees; DWV titers; Ectoparasites; Experiments; Gene expression; Genes; Homeostasis; Honey; honeybee; immune gene expression; Infections; Janus kinase; Kinases; Laboratory animals; Life span; MAP kinase; Mites; Parasitism; Pathogens; RNA-mediated interference; Signal monitoring; Ubiquitin; Ubiquitin-protein ligase; Varroa-DWV interaction; Viral infections; Virulence; Viruses; Wnt protein; Wounds
• ISSN: 2075-4450; 2075-4450
• DOI: 10.3390/insects10010016

The synergistic interactions between the ectoparasitic mite and (DWV) lead to the reduction in lifespan of the European honey bee and often have been implicated in colony losses worldwide. However, to date, the underlying processes and mechanisms that form the multipartite interaction between the bee, mite, and virus have not been fully explained. To gain a better understanding of honey bees' defense response to mite infestation and DWV infection, the DWV titers and transcription profiles of genes originating from RNAi, immunity, wound response, and homeostatic signaling pathways were monitored over a period of eight days. With respect to DWV, we observed low viral titers at early timepoints that coincided with high levels of Toll pathway transcription factor Dorsal, and its downstream immune effector molecules , , , and . However, we observed a striking increase in viral titers beginning after two days that coincided with a decrease in Dorsal levels and its corresponding immune effector molecules, and the small ubiquitin-like modifier (SUMO) ligase repressor of Dorsal, PIAS3. We observed a similar expression pattern for genes expressing transcripts for the RNA interference (Dicer/Argonaute), wound/homeostatic (Janus Kinase), and tissue growth (Map kinase/Wnt) pathways. Our results demonstrate that on a whole, honey bees are able to mount an immediate, albeit, temporally limited, immune and homeostatic response to and DWV infections, after which downregulation of these pathways leaves the bee vulnerable to expansive viral replication. The critical insights into the defense response upon and DWV challenges generated in this study may serve as a solid base for future research on the development of effective and efficient disease management strategies in honey bees.