Pyrrole produced by Pseudomonas aeruginosa influences olfactory food choice of Caenorhabditis elegans

Sense of smell can influence dietary choices in animals. So far, most of the research has focused on how animals respond to distinct odors when they are introduced individually. However, it remains unclear how animals evaluate foods that contain a bouquet of olfactory cues with contrasting effects. Here, we utilize Caenorhabditis elegans as a bacterivore to ask if odors produced by dietary bacteria can regulate worms food preferences. We show that the bacterium Pseudomonas aeruginosa produces a relatively small quantity of a new attractant for C. elegans. We identify the odor as a heterocyclic compound called pyrrole. We find that pyrrole contributes to the sensory decision-making of worms in diet preference assays. Using specific neuronal ablation lines and calcium response assays, we show that AWA odor sensory neurons of worms are necessary for sensing pyrrole. In all, we show that specific odors produced by bacteria can influence food choice behavior of animals.