The evolutionary origin of cnidocytes in the stinging black sponge Haliclona cnidata
The evolutionary origin of cnidocytes in the stinging black sponge Haliclona cnidata
2022-2024: LOEWE Center for Translational Biodiversity Genomics / LOEWE Zentrum für Translationale Biodiversitätsgenomik (TBG)
Project scientist: Dr. Jessica Reichert, Laura del Rio-Hortega, Tabea Platz
They are inconspicuous yet highly successful - marine sponges are evolutionary masters of defense and typically possess high levels of bioactivity to deter predators and competitors. In the case of the stinging black sponge (Haliclona cnidata), these mechanisms are complemented by "cellular weapons" in the form of functional cnidocytes (see Figure 1), usually known only from cnidarians such as jellyfish or corals.
The origin of these cnidocytes is still largely unknown. The sponge might take up the cells by kleptocnidism (translated as the stealing of cnidocytes). This involves taking up and storing cnidocytes or their precursor stages from other cnidarians such as corals in the environment. Alternatively, it may live in a symbiotic relationship with cnidarians that find shelter in its tissues and, in turn, produce and provide cnidocytes to the sponge. Alternatively, it might have even incorporated genes from the cnidarians into its own genome and can now build these cells on its own.
This projects aims to understand the origin of cnidocytes in the black stinging sponge using experimental laboratory research and genome analyses. The analysis of the sponge genome is a project at the LOEWE Center for Translational Biodiversity Genomics (LOEWE-TBG).
Figure 1: Sponges occur in marine habitats where they are important members of benthic environments. The stinging black sponge (Haliclona cnidata) is easy to overlook and has so far only been found in tropical marine aquaria (left). For its defense, like cnidarians, it has cnidocytes (nc) stored in the outer layer of its tissue, which are triggered upon distress and can inject a highly effective toxin into its attackers (right). Source: Schellenberg et al. (2019)