Abstract
Pollinators are in decline thanks to the combined stresses of disease,
pesticides, habitat loss, and climate. Honey bees face numerous pests
and pathogens but arguably none are as devastating as Deformed wing
virus (DWV). Understanding host-pathogen interactions and virulence of
DWV in honey bees is slowed by the lack of cost-effective
high-throughput screening methods for viral infection. Currently,
analysis of virus infection in bees and their colonies is tedious,
requiring a well-equipped molecular biology laboratory and the use of
hazardous chemicals. Here we describe cDNA clones of DWV tagged with
green fluorescent protein (GFP) or nanoluciferase (nLuc), providing
high-throughput detection and quantification of virus infections. GFP
fluorescence is recorded non-invasively in living bees via commonly
available long-wave UV light sources and a smartphone camera or a
standard ultraviolet transilluminator gel imaging system. Nonlethal
monitoring with GFP allows high-throughput screening and serves as a
direct breeding tool for identifying honey bee parents with increased
antivirus resistance. Expression using the nLuc reporter strongly
correlates with virus infection levels and is especially sensitive.
Using multiple reporters, it is also possible to visualize competition,
differential virulence, and host tissue targeting by co-occuring
pathogens. Finally, it is possible to directly assess the risk of
cross-species ‘spillover’ from honey bees to other pollinators and vice
versa.