Fatty Acid Smell, Anesthesia, and Use on Fruit Crops

International audienceOdors convey important information to select a sex partner, to find a food source, or to detect a danger. Among those some volatile molecules have been shown to cause a reversible anesthesia. However, their mode of action appears still largely mysterious. Here we describe a novel property of Olfactory Receptor 47b (OR47b), on olfactory sensory neurons (OSNs) expressing male-specific transcription factor FruM. We found some interesting properties of a fatty acid that can be present on food sources and oviposition sites for Drosophilid species. We show that OR47b neurons projecting to VA1v glomerulus are sensitive to this odor, and that this influences Drosophila behavior causing a strong aversion and even a reversible anesthesia. Strikingly, males are more sensitive than females to this acid. This effect is also adult specific, since larvae are highly attracted, and never anesthetized by this odor in contrary to carboxylic acid (CO2) or nitric oxide (NO). Furthermore, we observed that the anesthetic sex- specific effect is not displayed in a closely related species, Drosophila suzukii. Finally, we used this fatty acid on cherry crops and obtained a robust protection against D. suzukii. These findings reveal a spectacular evolutionary and stage-dependent sensitivity to some odors through a specific sensory pathway, which can be used to protect fruits in a safe manner for the ecosystem and the biodiversity