Rapid CommunicationChemotaxis behavior toward an odor is regulated by constant sodium chloride stimulus in Caenorhabditis elegans

•Chemotaxis of C. elegans toward an odor butanone was reduced by removal of NaCl from background.•Chemotaxis toward NaCl in a butanone or isoamyl alcohol background was not affected by the background.•In NaCl-free background, gustatory neurons ASE suppress the butanone-sensing neuron.

We studied the chemotaxis behavior of Caenorhabditis elegans toward a chemoattractant in the presence of background sensory stimulus. Chemotaxis toward an odor butanone was greater in the presence of sodium chloride (NaCl) than that without NaCl. By contrast, chemotaxis toward NaCl was not affected by a butanone background. The salt-sensing ASE neuron-deficient che-1(p674) mutants and worms with ASE genetically ablated showed high chemotaxis toward butanone, regardless of the presence of a NaCl background. Therefore, in wild-type worms, information from ASE in the absence of NaCl suppresses butanone chemotaxis, while the suppression is removed in the presence of NaCl.