The olfactory receptor SNIF-1 mediates foraging for leucine-enriched diets in <i>C. elegans</i>.

Abstract

Acquisition of essential nutrients through diet is crucial for the survival of animals. Dietary odors might enable animals to forage for nutrient-rich diets. We asked if <i>Caenorhabditis elegans</i>, a bacterivorous nematode, uses olfactory cues to forage for essential amino acid-rich (EAA) diets. Using the native microbiota of <i>C. elegans,</i> we show that worms rely on olfaction to select leucine (EAA)-supplemented bacteria. Using gas chromatography, we find that leucine-supplemented bacteria produce isoamyl alcohol (IAA) odor in the highest abundance. Prior adaptation of worms to IAA diminishes the diet preference of worms. Several wild isolates of <i>C. elegans</i> display robust responses to IAA, emphasizing its ecological relevance. We find that foraging for a leucine-supplemented diet is mediated via the AWC olfactory neurons. Finally, we identify SNIF-1 G protein-coupled receptor in AWC neurons as a receptor for IAA and a mediator of dietary decisions in worms. Our study identifies a receptor-ligand module underpinning foraging behavior in <i>C. elegans</i>.