Transcriptomic and proteomic analysis of marine nematode Litoditis marina acclimated to different salinities

Salinity is a critical abiotic factor for all living organisms. The ability to adapt to different salinity environments determines an organisms survival and ecological niches. Litoditis marina is a euryhaline marine nematode widely distributed in coastal ecosystems all over the world, although numerous genes involved in its salinity response have been reported, the adaptive mechanisms underlying its euryhalinity remain unexplored. Here, we utilized worms which have been acclimated to either low salinity or high salinity conditions and evaluated their basal gene expression at both transcriptomic and proteomic levels. We found that several conserved regulators, including osmolytes biosynthesis genes, transthyretin-like family genes, V-type H+-transporting ATPase and potassium channel genes, were involved in both short-term salinity stress response and long-term acclimation processes. In addition, we identified genes related to cell volume regulation, such as actin regulatory genes, Rho family small GTPases and diverse ion transporters, might contribute to hyposaline acclimation, while the glycerol biosynthesis genes gpdh-1 and gpdh-2 accompanied hypersaline acclimation in L. marina. Furthermore, gpdh-2 might play an essential role in transgenerational inheritance of osmotic stress protection in L. marina as in its relative nematode Caenorhabditis elegans. Hereby, this study paves the way for further in-depth exploration on adaptive mechanisms underlying euryhalinity, and may also contribute to the studies of healthy ecosystems in the context of global climate change.