Mass spectrometry-driven discovery of neuropeptides mediating nictation behavior of nematodes

Very little is known about the genetic modulation of nictation, a host-finding strategy used by infective juveniles of many pathogenic nematodes, as well as a phoretic strategy of Caenorhabditis elegans dauers. We here use a mass spectrometry-driven approach to find neuropeptides involved in the modulation of this behavior. We identified 126 neuropeptides in infective juveniles of the commercially relevant entomopathogenic nematode Steinernema carpocapsae, 75 of which have orthologs in the model organism C. elegans. To prioritize candidates for causality testing in light of the stage-restricted nictation behavior, we developed a targeted approach to carry out quantitative neuropeptidomics measurements in C. elegans. Our results show that virtually all 164 quantified neuropeptides are more abundant in dauers compared to L3 juveniles. Amongst these, we identify at least the neuropeptide genes flp-7 and flp-11 as novel regulators of nictation.