Beets, Isabel, Dalzell, Johnathan, Lee, Junho, Yang, Heeseung, Van Bael, Sven, Vandewyer, Elke, Kieswetter, Amanda, Boelen, Rose, Cockx, Bram, Temmerman, Liesbet
[
International Worm Meeting,
2021]
Emerging evidence suggests that behavioral changes associated with host finding of pathogenic nematodes may be regulated by neuropeptides. Hence, we started from peptidomic discovery in such a species, Steinernema carpocapsae, to direct functional discovery. We observe numerous similarities between the well-studied C. elegans peptidome and the S. carpocapsae peptidome, which we further exploit to understand neuropeptidergic contributions to regulating nictation, an evolutionary conserved behavior for foraging in (these) nematodes. An in-house method based on acidified methanol was used to extract endogenous neuropeptides of Steinernema carpocapsae infective juveniles, a life stage similar to the C. elegans dauer stage. Neuropeptide identification was done by state-of-the-art UHPLC-MS/MS. We detected 30% (139) of the predicted peptidome in these infective juveniles, which provides a resource for comparison with the C. elegans dauer peptidome (in house). We hypothesized that nictation-relevant peptides will be abundant in infective juveniles and/or dauers, and prioritized these for functional assays. Out of several tested target genes, we found at least one neuropeptidergic signaling system that is involved in modulation of nictation behavior, which we assayed using microdirt arenas. In addition, using phylogenetic analyses, we aim to get a better global understanding of conserved peptidergic signaling systems in parasitic and free living nematodes. Steinernema spp. are used as eco-friendly alternative for chemicals to combat pest insects. Knowledge on neuropeptidergic regulation of host-finding strategies will help understand how entomopathogenic nematodes regulate their behavior. This should contribute to improving their applicability and host specificity in the field.