(2nd Place) Engineered microalgae feed to bolster honey bee disease resistance

Pathogenic diseases threaten the global beekeeping industry by weakening honey bee (Apis mellifera) health and productivity. To combat record colony losses, beekeepers urgently need access to effective, practical, and sustainable treatments against pathogens. Addressing this problem, we have genetically engineered microalgae to express dsRNA specific to honey bee pathogens. When consumed, these dsRNA-producing engineered strains provide dietary amino acids that support honey bee nutrition and also induce an RNAi immune response against target pathogens. In previous work, we determined that adult bees fed engineered microalgae that produces DWV-targeting dsRNA show reduced viral load after injection with DWV compared to controls. Here, we test whether this microalgae-induced disease resistance can also be conferred to younger life stages. In this study, honey bee larvae were reared in vitro on royal jelly diets containing either non-engineered microalgae (Vector), non-specific dsRNA-producing engineered microalgae (YFP), or DWV-targeting engineered microalgae (DWV1 and DWV2). The resulting pupae who were reared on DWV-targeting microalgae diets had lower DWV load 48 and 72 hours post injection compared to controls. Our results show that engineered microalgae feed additives have potential to benefit whole colonies by dually supporting proper nutrition and improving disease resistance across all life stages of bees. Engineered microalgae feed additives represent a highly scalable, sustainable, and effective opportunity to bolster honey bee health.