The role of venom in coral resilience

Coral reefs are iconic marine ecosystems, sustaining the highest number of marine species per unit area in the ocean. They also have a high economic value as they provide multiple ecosystem services worldwide. Global climate change is leading to the decline of coral reefs, mostly due to the phenomenon of coral bleaching associated to the rise in sea water temperatures. This year, reefs are experiencing the fourth global coral bleaching event. The critical challenge to develop new coral conservation approaches requires a more detailed understanding of coral biology at organismal, cellular and molecular levels. Corals obtain nutrients either autotrophically through their intracellular symbiotic dinoflagellates or by feeding on planktonic prey (heterotrophy). The symbionts provide the corals with up to 90% of the total energy. During bleaching, the symbionts are lost and coral risk starvation, often leading to death. However, many corals can survive some episodes of bleaching by increasing their capability for heterotrophic feeding. Corals belong to Cnidaria, a group including some of the most venomous organisms in the ocean such as jellyfish and sea anemones. As such, to catch their prey, corals use venom produced by specialised stinging cells. Venom contains a complex mixture of protein, small molecule and peptide toxins. Venoms are metabolically expensive to synthesize but they can play a key role in allowing corals to overcome energy depletion during bleaching and therefore might be a key resilience mechanism. In fact, sea anemones, close relatives of corals, maintain venom production under bleaching. However, under the heat they adjust the levels of individual toxins to meet the energy demands of the stressed animals. Research has focussed on the very potent jellyfish and sea anemone venoms, mostly due to their impact on human health and pharmaceutical industry. Much less is known about the composition of venom in corals and in particular its role in coral nutrition and responses to environmental disturbance. To address this knowledge gap, the main aim of this project is to define the molecular identity of coral venom and establish its role in surviving bleaching in corals. We have established three key objectives for this work: (1) to reveal the role of heterotrophic feeding in post-bleaching recovery in a range of coral species; (2) to identify venom components in stony corals; (3) to characterise toxin production dynamics under bleaching stress in corals. We have brough together a team of experts in biochemistry and ecology of venom and coral biology. We will benefit from access to modern high-end coral aquaria maintaining dozens of coral species under controlled conditions and will use a set of cutting edge bioinformatics and molecular laboratory techniques (genomics, transcriptomics, proteomics, microscopy) in combination with experiments on live corals to study feeding and venom biosynthesis at organismal, molecular and cellular levels. The outcomes of this project will provide new insights into fundamental aspects of coral biology: venom-mediated feeding and its role in resilience to the environmental stress. This knowledge will lead to a step change in understanding coral physiology that is urgently required to support the design of efficient strategies for coral conservation. Coral conservationists and scientists in the areas of coral biology, invertebrate zoology, marine ecology, and animal venoms will be obvious beneficiaries of this research. Additionally, newly identified coral toxins will likely also have applications in the development of new pharmaceuticals.