Location: Honey Bee Breeding, Genetics, and Physiology Research
Project Number: 6050-21000-016-022-R
Project Type: Reimbursable Cooperative Agreement
Start Date: May 15, 2022
End Date: Jan 31, 2025
Objective:
1. Demonstrate a fast, nonlethal method for screening and selecting virus resistant honey bee drones (drones that do not develop high Deformed Wing Virus (DWV) titers after DWV injection).
2. Inseminate queens using semen from drones with confirmed DWV resistance and propagate subsequent generations of honey bees that exhibit enhanced viral resistance.
Approach:
We propose to inject drones with the proven Deformed Wing Virus (DWV)-luciferase cDNA clone, and subsequently assess injected DWV replication and DWV load at 48 hours post-injection, a time confirmed to distinguish between high and low viral infections (Evans/Beeporter). We will then select the drones displaying the most reduced and most elevated DWV viral titers as indicated by luminescence. Sperm from these drones will be used to produce progeny with phenotypic extremes of DWV resistance or susceptibility. We will use artificial insemination via typical instrumental apparatus, followed by production of offspring of single-drone inseminated queens with putatively higher and lower levels of viral resistance. Inseminating queens with semen from drones carrying the lowest DWV loads post-injection, and also inseminating queens with semen from drones with the highest ultraviolet (UV) luminescence post-injection should produce offspring with phenotypic extremes of the DWV resistant/susceptible trait. Once the initial F1 artificial inseminated (AI) queens have initiated oviposition we will graft first instar larvae to produce an F2 queen generation. Following the same approach as described we will test the worker offspring of the F1 AI queens by injection of nLuc-DWV cDNA clones and measure viral titers by bioluminescence and confirm by q-RT-PCR. We propose to duplicate that trial at least twice more, and perhaps three iterations, in a single season. By the end of this first full queen-rearing season (after the award of funds) we should have an indication of the viability of the method for producing and improving DWV-resistant breeding stock. We anticipate that mean and median colony DWV resistance, as measured by post-nLuc/DWV cDNA injection will change, and that the worker offspring in each subsequent generation will demonstrate less variance. Also, having phenotypic extremes of DWV resistant and DWV susceptible bees should facilitate current efforts to elucidate the genomic elements and transcriptomic networks associated with virus resistance, providing a windfall for further research and development.
