Controlling the hungry starfish
The Crown-of-Thorns Starfish (COTS) Acanthaster planci plays an important role in maintaining a healthy coral reef population in it’s native habitat in the Indo-Pacific region by digesting fast-growing corals. Probably because of increased water temperatures, increased nutrients running off from land to water and increased fishing of the starfish’s natural predators, populations and distribution have increased significantly. The great barrier reef and other important biodiversity hot spots are being threatened by these outbreaks (along with other threats) as the COTS are eating they way through the reef. The outbreaks of starfish are more dangerous to the reefs than bleaching events and disease infections combined!
Counter-control measures by humans currently focus on injections of sodium bisulphate by divers - or maybe by robots in the future. Even though a trained diver might be able to kill over 100 COTS per hours, this work is difficult and will not reach all underwater areas.
Now the genome of Acanthaster planci was sequenced and analysed by researchers at the University of Queensland's Centre for Marine Science in Brisbane (Professor Bernard Degnan from the School of Biological Sciences as the corresponding author). It was published in Nature (Michael R. Hall et al.: The crown-of-thorns starfish genome as a guide for biocontrol of this coral reef pest) and might lead to new methods of population control in this and other species.
The team also analysed the proteins released by COTS using mass spectrometry, looked at the potentially active domains and compared their genes. The hope was to isolate candidate proteins that are secreted and act as a chemical aggregation signal. When many individuals can be gathered together using these signals artificially, they would be easier to control and capture. In particular G-protein coupled receptor proteins (GPCRs) were analysed as potential receptors of the signal in the cell membrane.