A Transmissible RNA Pathway in Honey Bees

• Published in: Cell reports (Cambridge) 2019-05, Vol.27 (7), p.1949-1959.e6
• Main Authors: Maori, Eyal, Garbian, Yael, Kunik, Vered, Mozes-Koch, Rita, Malka, Osnat, Kalev, Haim, Sabath, Niv, Sela, Ilan, Shafir, Sharoni
• Format: Article
• Language: English
• Subjects: environmental RNA; eRNA; extracellular RNA; Honey bees; RNA transmission; RNAi; RNP; royal jelly; transmissible RNA; viruses
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2019.04.073

Systemic RNAi, initiated by double-stranded RNA (dsRNA) ingestion, has been reported in diverse invertebrates, including honey bees, demonstrating environmental RNA uptake that undermines homologous gene expression. However, the question why any organism would take up RNA from the environment has remained largely unanswered. Here, we report on horizontal RNA flow among honey bees mediated by secretion and ingestion of worker and royal jelly diets. We demonstrate that transmission of jelly-secreted dsRNA to larvae is biologically active and triggers gene knockdown that lasts into adulthood. Worker and royal jellies harbor differential naturally occurring RNA populations. Jelly RNAs corresponded to honey bee protein-coding genes, transposable elements, and non-coding RNA, as well as bacteria, fungi, and viruses. These results reveal an inherent property of honey bees to share RNA among individuals and generations. Our findings suggest a transmissible RNA pathway, playing a role in social immunity and signaling between members of the hive. [Display omitted] •Ingested dsRNA spreads via hemolymph and is secreted in worker and royal jellies•Functional dsRNA flows horizontally among honey bees by jelly consumption•Worker and royal jellies harbor differential natural ssRNA and dsRNA populations•Diverse pathogenic RNA fragments naturally occur in worker and royal jellies RNA mobility among cells has been documented in plants and animals. Maori et al. show that RNA spreads further in honey bees and is horizontally transferred between individuals and across generations. Their findings demonstrate a transmissible RNA pathway with potential roles in social immunity and epigenetic communication between honey bees.