Project description:Corals in nearshore marine environments are increasingly exposed to reduced water quality, which is the major local threat to coral reefs in Hawaii. Corals surviving in such conditions may have adapted to withstand sedimentation, pollutants, and other environmental stressors. Lobe coral (Porites lobata) populations from Maunalua Bay, Hawaii showed clear genetic differentiation along with distinct cellular protein expressions between the 'polluted, high-stress' nearshore site and the 'low-stress' offshore site. To understand the driving force of the observed genetic partitioning, reciprocal transplant and common-garden experiments were conducted using the nearshore and offshore colonies of P. lobata from Maunalua Bay to assess phenotypic differences between the two coral populations. Stress-related physiological and molecular responses were compared between the two populations. Proteomic responses highlighted the inherent differences in the cellular metabolic state and activities between the two populations under the same environmental conditions; nearshore corals did not significantly alter their proteome between the sites, while offshore corals responded to the nearshore transplantation with increased abundances of proteins associated with detoxification, antioxidant, and various metabolic processes. The response differences across multiple phenotypes suggest that the observed genetic partitioning was likely due to local adaptation.
Project description:An adult P. rus colony was imported from Indonesia following the CITES protocols (Permit number 14846/IV/SATS-LN/2007) and kept in the Animal Facilities of the Justus Liebig University, Giessen. The colony was maintained in a circulating artificial seawater system at approximately 26 °C with 20-40 µmol photons m-2s-1 (T5 light) of photosynthetically active radiation on a 10:14 h light-dark cycle. A fragment of approx. 9 cm2 was separated from the colony and used as a source of tissue for hologenomic DNA/RNA isolation. Tissue was removed by scraping the fragment´s surface with a sterilized razor blade.