Mémoire
| Résumé : | Reef-building corals rely on a symbiotic relationship between coral polyps andSymbiodiniaceae. Although coral biology is often studied in the context of globalchange, the impact of light intensity on this symbiosis remains underexplored,hindering the potential use of light reduction as a protection against coralbleaching. To investigate, we tested the response of the endemic coralMontipora capitata (34 colonies) to different light levels in a field experiment inK¯ane‘ohe Bay, O‘ahu, Hawai‘i, using Data-Independent Acquisition (DIA)proteomics. Non-metric multidimensional scaling (NMDS) showed significanteffects of light and genotype on the coral proteome (p = 0.032 and p = 0.007),while Symbiodiniaceae exhibited minimal response. In M. capitata, 69 proteinsdiffered signiciantly in abundance between light levels, among which 19 proteinsincluding catalase (CAT), superoxide dismutase (SOD2), peptidases andinhibitors, and calcium transport upregulated in low light and 50 proteinsinvolved in genetic processes, protein turn-over and other metabolic processes,upregulated in high light. Symbiodiniaceae showed minor changes, withphotosynthesis proteins upregulated in low light and fatty acid metabolism inhigh light. Overall, M. capitata and its symbionts responded to varying lightlevels emphasizing different protective and metabolic changes under both lightconditions—demonstrating their capacity to handle varying environmentalpressures. These findings suggest that shaded corals do not experiencesignificant stress or metabolic imbalances compared to those exposed to ambientlight, highlighting shading as a promising strategy for mitigating coral bleaching. |
