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dc.contributor.advisorFinnerty, Johnen_US
dc.contributor.authorNguyen, Lindaen_US
dc.date.accessioned2020-11-12T14:20:39Z
dc.date.available2020-11-12T14:20:39Z
dc.date.issued2020
dc.identifier.urihttps://hdl.handle.net/2144/41678
dc.description.abstractCorals are critical to marine biodiversity and human welfare. Coral reefs cover <1% of the seafloor but support ~1/3 of all marine species. Approximately 1.5 billion people live within 100 km of coral reefs, relying upon them for food, income from tourism, and protection from storms. Their economic value has been estimated at $375 billion annually. The foundation of coral reefs is the intracellular symbiosis between corals and photosynthetic dinoflagellates of the family Symbiodiniaceae. Tropical corals satisfy up to 95% of their nutritional requirements through photosynthesis, and their ability to construct reefs is biochemically coupled to photosynthesis. While permitting corals to thrive, photosymbiosis also increases their exposure to environmental stressors and vulnerability to climate change. Reliance on photosynthesis restricts reef-building corals to shallow, clear, tropical waters, where they experience higher temperatures and UV exposure. The generation of reactive oxygen species by the symbiont also exposes corals to greater oxidative stress. The symbiosis is particularly sensitive to climate change: all of the mass coral bleaching events have occurred since 1982, driven by elevated ocean temperatures. Molecular cross-talk between host and symbiont impacts resilience of the coral holobiont and resistance to bleaching. Unfortunately, we know little about how photosymbiosis impacts expression or activity of coral genes. Tropical corals engage in an obligate symbiosis with Symbiodiniaceae, so we cannot study their gene expression in a stable aposymbiotic state. However, the northern star coral, Astrangia poculata, engages in a facultative symbiosis with Symbiodiniaceae. I used RNA sequencing to investigate how symbiosis impacts gene expression in A. poculata, focusing on genes implicated in photosymbiosis: antioxidant enzymes (specifically superoxide dismutases) and the NF-κB signaling pathway. From an improved transcriptome assembly, I recovered core elements of a primitively simple NF-κB signaling pathway and a rich complement of SOD proteins. 273 coral transcripts—many associated with protein metabolism and vesicle-mediated transport— were differentially expressed in symbiotic versus aposymbiotic corals. Unlike in the facultatively symbiotic sea anemone Exaiptasia, symbiosis was not associated with depressed NF-κB transcript levels. IKKε, a potential positive regulator of NF-κB activity, was strongly up-regulated, as was one particular superoxide dismutase.en_US
dc.language.isoen_US
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 Internationalen_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/4.0/
dc.subjectBiologyen_US
dc.subjectCoralsen_US
dc.subjectNF-kBen_US
dc.subjectRNA-seqen_US
dc.subjectSODen_US
dc.subjectSuperoxide dismutaseen_US
dc.subjectTranscriptomicsen_US
dc.titleThe effects of photosymbiosis on gene expression in the facultatively symbiotic coral Astrangia poculata, with a focus on NF-kappaB signaling and antioxidant enzymesen_US
dc.typeThesis/Dissertationen_US
dc.date.updated2020-11-09T20:02:27Z
etd.degree.nameDoctor of Philosophyen_US
etd.degree.leveldoctoralen_US
etd.degree.disciplineBiologyen_US
etd.degree.grantorBoston Universityen_US
dc.identifier.orcid0000-0002-3489-1230


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