Coral reefs are profoundly important, diverse ecosystems that are threatened worldwide by environmental variation and stress. They have huge economic value as fisheries, storm barriers and destinations for ecotourism. Corals are made up of large numbers of interconnected animal hosts, called polyps that house microscopic algae inside their cells. This partnership, or symbiosis, is the foundation of the entire coral reef ecosystem. The polyps receive photosynthetic nutrients from the algae, and the algae receive nutrients from the polyps. While a great deal of attention has been focused on the environmental threats to corals, there remains only a partial understanding of the microscale cellular, molecular, and genetic mechanisms that underpin the coral-algal symbiosis. Insight into regulation of this symbiosis will provide a stronger foundation for studies of coral health and coral stress, such as coral bleaching in which the host polyps lose their symbiotic algae. This project will bring together a diverse team of coral biologists, cell biologists and geneticists to study a small sea anemone that serves as an excellent proxy for corals, which do not survive well in the lab, are slow growing, and difficult to collect because of their endangered status. In contrast, the fast-growing, weedy sea anemone Aiptasia will enable the researchers to make rapid progress on the study of coral symbiosis. This award is focused on technique development and swift dissemination of results through online communication platforms to both the scientific community and the public. A variety of genetic techniques will be developed, including gene editing in both partners to be able to test hypotheses about the involvement of specific genes in coral health and stress. To increase the effectiveness and efficiency of research efforts to understand the cellular, molecular and genetic foundations of this symbiosis, the researchers will develop and optimize approaches to rear the complete life cycle of Aiptasia in the laboratory. This award will contribute to the training of scientists and expose school-aged children and the general public to coral reef and symbiosis science.
The ecological, economic, and aesthetic importance of coral reefs is widely recognized, as are the threats they face from environmental stress. Nonetheless, the underlying molecular and cell biology of corals and their resident endosymbiotic dinoflagellates (genus Symbiodinium) that are critical for host nutrition remain poorly understood. A major reason for this paucity of knowledge is the lack of methods for mutant isolation and analysis, gene knockdown, gene knockout, and gene tagging. Without these, even powerful genomic and transcriptomic analysis largely yield correlations whose implications for causal mechanisms remain uncertain. This project focuses on development of approaches to test gene function in a rapidly developing model system, the sea anemone Aiptasia and the Symbiodinium minutum (Clade B1) strain SSB01, which can form a stable endosymbiosis with Aiptasia, and can grow well in culture. Genetic manipulation in SSB01 and in small polyps will include morpholino and CRISPR/Cas9 approaches to achieve gene knockdown, knockout and gene tagging. The researchers will identify and test compounds from natural substrates and biofilms to achieve larval settlement, and will identify and test anemone neuropeptides as a means to achieve metamorphosis of Aiptasia routinely in the laboratory. Finally, a set of interwoven communications platforms and activities will be developed to rapidly disseminate information gained in the project to the broader scientific community.
