Project description:The Crown-of-thorns starfish (COTS) Acanthaster planci feeds on hard corals and its outbreaks are a major cause of destruction of coral communities on the Australian Great Barrier Reef. Whilst population booms and the social behaviour of COTS have been well studied, little is known about the neural mechanisms underlying COTS metabolism and behaviour. One of the major classes of chemical messengers that regulate metabolic and behavioural processes in animals are neuropeptides. Here, we have analysed COTS genome and transcriptome sequence data to identify neuropeptide precursor proteins in this species. Mass spectrometry was employed to identify neuropeptides extracted from radial nerve cords. Forty-nine neuropeptide precursors were identified, including homologs of neuropeptide signaling systems that are evolutionarily conserved throughout the Bilateria.
Project description:The Crown-of-Thorns starfish (COTS), Acanthaster planci, is a highly fecund predator of reef-building corals distributed throughout the Indo-Pacific. COTS population outbreaks cause substantial loss of coral cover, diminishing the integrity and resilience of the reef ecosystems thus increasing their susceptibility to climate change. We sequenced genomes of A. planci from the Great Barrier Reef, Australia (GBR) and Okinawa, Japan (OKI) to guide identification of species-specific peptide communication with potential applications in mitigation strategies. The genome-encoded proteins excreted and secreted into the surrounding seawater by COTS forming aggregations and by those escaping the predatory giant triton snail, Charonia tritonis, were identified LC-MS/MS.
Project description:Transcriptional responses to heat stress were assayed in early life-history stages of 11 crosses between and amongst Acropora tenuis colonies originating from reefs along the Great Barrier Reef. We identified a single nucleotide polymorphism outlier (Fst=0.89) between populations in the unannotated gene Acropora25324, which exhibited constitutively higher gene expression in populations with dams originating from Curd reef, a far north, warm adapted inshore reef, suggesting an important role of this gene in adaptation to warmer environments. Further, juveniles exposed to heat and in symbiosis with heat-evolved Symbiodiniaceae displayed intermediate transcriptional responses between its progenitor taxa (Cladocopium goreaui) and the more stress tolerant Durusdinium trenchii, indicating that the development of heat tolerance acquisition is potentially a conserved evolutionary process in Symbiodiniaceae. These findings reveal the underlying mechanisms, and for the first time, their relative contribution, of coral responses to climate change and provide a foundation for optimizing conservation methods like assistant gene flow.