Engineered symbionts activate honey bee immunity and limit pathogens

Engineered symbionts activate honey bee immunity and limit pathogens

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P. Leonard Sean, J. E. Powell, J. Perutka, P. Geng, C. Heckmann Luke, D. Horak Richard, W. Davies Bryan, D. Ellington Andrew, E. Barrick Jeffrey and A. Moran Nancy,  Science,  367:573-576. 2020.

Honey bees are essential pollinators threatened by colony losses linked to the spread of parasites and pathogens. Here, we report a new approach for manipulating bee gene expression and protecting bee health. We engineered a symbiotic bee gut bacterium, Snodgrassella alvi, to induce eukaryotic RNA interference (RNAi) immune responses. We show that engineered S. alvi can stably recolonize bees and produce double-stranded RNA to activate RNAi and repress host gene expression, thereby altering bee physiology, behavior, and growth. We used this approach to improve bee survival after a viral challenge, and we show that engineered S. alvi can kill parasitic Varroa mites by triggering the mite RNAi response. This symbiont-mediated RNAi approach is a tool for studying bee functional genomics and potentially for safeguarding bee health.