Summary
Odors are intimately tied to the taste system to aid food selection and determine the sensory experience of food. However, how smell and taste are integrated in the nervous system to drive feeding behavior remains largely unknown. We show in Drosophila that odors alone activate gustatory receptor neurons (GRNs) and trigger proboscis extension reflex (PER), a canonical taste-evoked feeding behavior. Odor-evoked PER requires the function of sugar-sensing GRNs but not the olfactory organs. Calcium imaging shows that GRNs directly respond to odors. Odor-evoked PER is mediated by the Gr5a receptor, and is bidirectionally modulated by specific olfactory binding proteins. Finally, odors and sucrose co-applied to GRNs synergistically enhance PER. These results reveal a cell-intrinsic mechanism for odor-taste multimodal integration that takes place as early as in GRNs, indicating that unified chemosensory experience is a product of layered integration in peripheral neurons and in the brain.
Competing Interest Statement
The authors have declared no competing interest.
