Project title: Gas-powered reefs: Is isoprene the key to thermal resilience amongst reef building corals?
Supervisor: David Suggett
Co-Supervisors: Justin Seymour & Jean-Baptiste Raina
Reef building corals have suffered immense declines globally. It is now well established that specific genotypes of the algal symbionts harboured by corals (Symbiodinium spp.) are better adapted to withstanding transient heat stress than others. In efforts to minimise impacts of heat stress, corals and their algal symbionts produce a range of secondary metabolites, including Biogenic Volatile Organic Compounds (BVOCs). BVOCs are utilised in a wide variety of processes, they can function as osmolytes, aid in excess energy dissipation, assist in thermotolerance and function as antioxidants. A BVOC called isoprene may play a central role in heat stress tolerance in these organisms. Isoprene is widely recognised to provide thermo-tolerance to higher plants. Only one study has examined production of isoprene from a small representation of the overall diversity for Symbiodinium (Exton et al. 2013), but it has been recently postulated that a correlation might exist between thermo-tolerance and isoprene production in Symbiodinium (Exton et al. 2015). This hypothesis is based on elevated isoprene production by more thermally tolerant Symbiodinium genotypes under steady state growth (Exton et al. 2013, 2015); whether stress tolerance is explicitly linked to greater isoprene production remains completely untested. Furthermore, while isoprene is a key metabolite utilised by microbes in marine ecosystems, the manner in which production of isoprene further influences the corals’ microbial community to ultimately regulate atmospheric emissions of isoprene is also unknown.
To quantify isoprene production for a range of coral-symbiont-bacterial associations under steady state growth conditions and in response to transient heat stress perturbations. To determine whether coral microbial communities harbour potential isoprene consuming bacteria and to establish whether a relationship exists between up-regulation of isoprene production and the thermal susceptibility of the coral holobiont.