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In a new study published in the journal Science, researchers from The University of Texas at Austin outline their novel approach to protecting honey bees at risk of colony collapse – genetically engineered bacteria.





What is colony collapse? Colony collapse disorder occurs when the majority of worker bees within a colony disappear and leave behind a queen, surplus food and a limited number of nurse bees to take care of the queen and any immature bees in the colony.

The number of bee colony deaths continue to rise, according to the Bee Informed Partnership's latest survey. The results show that for the entire survey period (1 April 2018 – 1 April 2019), beekeepers in the U.S. lost an estimated 40.7% of their managed honey bee colonies – slightly higher than the rate of loss reported in the 2010-2011 survey (37.8%).



A common parasite, the Varroa mite, is a major contributor to colony loss, in addition to the deformed wing RNA virus. Varroa mites and deformed wing virus often come hand-in-hand. The mites feeding on the bees spread the virus and thus weaken the bees’ immune system, meaning they are more vulnerable to environmental pathogens.





A more welcomed guest





Novel method is the "bee’s knees"



Long-term, sustained manipulation of bee gene expression has proven difficult, due to patchy gene expression and off-target effects.

Therefore, the scientists turned to the gut bacterium S. alvi, genetically engineering the bacterium to continuously produce double-stranded RNAs to manipulate the bee's gene expression in situ.







A pesty problem



Honey bees play a large role in global food production,

every year to the value of U.S. crop production. Colony collapse can therefore have detrimental effects on global food resources.



Is the work of Moran and team a viable solution to preventing pest-related issues in honey bees? It's possible, and the fact that the bacterium used in the experiment are highly specialized and cannot survive outside of the bee gut for long, is certainly a bonus.



However, the authors caution that further work is required to assess the effectiveness and safety of the treatments if they are to be used in an agricultural setting.



A second application of this research is the creation of a tool for studying bee genetics. The ability of the engineered bacteria to knock down host genes in the bee permits the study of the bee genome, which could enable research into novel breeding strategies.



Reference: Leonard et al. (2020). Engineered symbionts activate honey bee immunity and limit pathogens. Science. DOI: 10.1126/science.aax9039.