Exploiting your host’s “dreams and desires”: Viral utilization of flower/pollinator interactions

Background/Question/Methods

Viruses are dependent upon efficient transmission from one host to another for continual infection and replication.  Several groups of RNA viruses that infect either plants or pollinators have made use of pollinator/plant relationship, exploiting pollen as an efficient mechanism for transmission among several host genera.   Experimental evidence for this mechanism will be explored using controlled transmission studies, phylogenetic analyses of viral genomes from different host species, and from published studies.   The broader evolutionary question of viral evolution and exploitation of both the plant and insect pollinator will be addressed—does the pollinator/flower interaction enable host switching and promote viral evolution?

Results/Conclusions

The interactions of pollinators and flowers is a mutualistic relationship, satisfying the “desire” of the pollinator for a nutritious protein source and the “dreams” of the plant for fitness through sexual reproduction.  Viruses have exploited this interaction to enable efficient transmission between different hosts and host species.  This interaction may have promoted host switching throughout evolutionary history as evidenced by phylogenetic analysis of several groups of viruses infecting pollinators and from new reported discoveries.  For the pollinator species, we demonstrate that Israeli Acute Paralysis virus is actively infecting honey bees, bumble bees, and solitary bees with negative impacts on all species.   For pollinator health, the transmission of viruses via pollen is also a potential weak link in the health of both the pollinator and the plants they visit.   Those interested in supplementing the diets of honey bees or rearing bumble bees should avoid using imported pollen sources that may enable introduction of plant pathogens and new viral species infecting pollinators into a local environment.