Reciprocal transplantation of the heterotrophic coral Tubastraea coccinea (Scleractinia: Dendrophylliidae) between distinct habitats did not alter its venom toxin composition

Abstract

Tubastraea coccinea is an azooxanthellate coral species recorded in the Indian and Atlantic oceans and is presently widespread in the southwestern Atlantic with an alien status for Brazil. T. coccinea outcompete other native coral species by using a varied repertoire of biological traits. For example, T. coccinea has evolved potent venom capable of immobilizing and digesting zooplankton prey. Diversification and modification of venom toxins can provide potential adaptive benefits to individual fitness, yet acquired alteration of venom composition in cnidarians is poorly understood as the adaptive flexibility affecting toxin composition in these ancient lineages has been largely ignored. We used quantitative high‐throughput proteomics to detect changes in toxin expression in clonal fragments of specimens collected and interchanged from two environmentally distinct and geographically separate study sites. Unexpectedly, despite global changes in protein expression, there were no changes in the composition and abundance of toxins from coral fragments recovered from either site, and following clonal transplantation between sites. There were also no apparent changes to the cnidome (cnidae) and gross skeletal or soft tissue morphologies of the specimens. These results suggest that the conserved toxin complexity of T. coccinea co‐evolved with innovation of the venom delivery system, and its morphological development and phenotypic expression are not modulated by habitat pressures over short periods of time. The adaptive response of the venom trait to specific predatory regimes, however, necessitates further consideration.

The influence of ecological factors on cnidarian venoms

“…The global proteome (the total complement of proteins in the venom) from the heterotrophic coral Tubastraea coccinea has been shown to change over time, if a population is transplanted from one geographic location to another (separated on a small regional scale ~40 km). However, the actual composition of toxic venom components remained identical in all populations, thus evidencing no change ( Kitahara et al, 2020 ), which is interesting as the authors specifically note very different environmental conditions between the two sites. This lack of venom change is consistent with the findings of McClounan and Seymour (2012) in the analysis of the previously mentioned C. fleckeri venom over small geographic scales.…”

Characterising Functional Venom Profiles of Anthozoans and Medusozoans within Their Ecological Context

“…Similar variability in venom protein content was observed in the scyphozoan giant jellyfish, Nemopilema nomura, sourced from a number of locations in the Yellow Sea [56]. In contrast, when clonal fragments of the scleractinian coral, Tubastraea coccinea, were reciprocally transplanted between inshore and offshore sites for a six week period, no changes to the abundance and composition of recognised toxins were detected, despite altered expression of non-toxin peptides [57]. Whether this unchanged venom profile is a consequence of similarity in biotic communities between the two locations, the short duration of this study, or is a common attribute of corals and other sessile cnidarians, remains to be determined.…”

Biochemical and Toxinological Characterization of Venom from Macrorhynchia philippina (Cnidaria, Hydrozoa)

“…In general, hydrozoans have a predominance of phospholipases, cytotoxins, and hemolysins [ 24 ], whereas its jellyfishes have metallopeptidases, neurotoxins, and serine peptidases [ 9 ]. Also, the venom of Tubastraea coccinea was determined to harbor several neurotoxins, cytolysins, and dyshomeostasis [ 25 ]. On the other hand, the venom of M. philippina does not contain protein toxins, and the toxic effects were elicited by low molecular mass compounds.…”