Project description:This SuperSeries is composed of the following subset Series: GSE12809: Symbiodinium clade content drives host transcriptome more than thermal stress in the coral Montastraea faveolata (part 1) GSE15253: Symbiodinium clade content drives host transcriptome more than thermal stress in the coral Montastraea faveolata (part 2) Refer to individual Series
Project description:The potential to adapt to a changing climate depends in part upon the standing genetic variation present in wild populations. In corals, the dispersive larval phase is particularly vulnerable to the effects of environmental stress. Larval survival and response to stress during dispersal and settlement will play a key role in the persistence of coral populations. To test the hypothesis that larval transcription profiles reflect population specific responses to thermal stress, symbiont-free gametes of the scleractinian coral Montastraea faveolata were collected from Florida and Mexico and raised under normal and elevated temperatures. These populations have been shown to exchange larvae frequently enough to prevent significant differentiation of neutral loci. Differences among thousands of genes were simultaneously characterized using microarrays, allowing investigation of gene expression patterns among wild populations under stressful environmental conditions. Results show site-specific signatures of gene expression in larvae of a reef-building coral from different parts of its range (despite low genetic divergence), and reveal both local and general components of stress response during later stages of larval development. These results provide evidence of site-specific variation in the face of gene flow, which may represent functional genetic variation in different subpopulations, and support the idea that coral host genomes may indeed house the adaptive potential needed to deal with changing environmental conditions.
Project description:The potential to adapt to a changing climate depends in part upon the standing genetic variation present in wild populations. In corals, the dispersive larval phase is particularly vulnerable to the effects of environmental stress. Larval survival and response to stress during dispersal and settlement will play a key role in the persistence of coral populations. To test the hypothesis that larval transcription profiles reflect population specific responses to thermal stress, symbiont-free gametes of the scleractinian coral Montastraea faveolata were collected from Florida and Mexico and raised under normal and elevated temperatures. These populations have been shown to exchange larvae frequently enough to prevent significant differentiation of neutral loci. Differences among thousands of genes were simultaneously characterized using microarrays, allowing investigation of gene expression patterns among wild populations under stressful environmental conditions. Results show site-specific signatures of gene expression in larvae of a reef-building coral from different parts of its range (despite low genetic divergence), and reveal both local and general components of stress response during later stages of larval development. These results provide evidence of site-specific variation in the face of gene flow, which may represent functional genetic variation in different subpopulations, and support the idea that coral host genomes may indeed house the adaptive potential needed to deal with changing environmental conditions. The experimental setup followed a reference design, i.e. all samples were hybridized against the same pool made up of equal amounts of RNA from all samples collected in Mexico. For samples from Mexico we used three technical replicates for each treatment temperature, for samples from Florida three biological replicates were used for each treatment temperature, except for the high temperature samples at day two where only two replicates were available due to high larval mortality at that temperature. Common reference samples were labeled with Cy3, temperature treatment samples with Cy5. Microarrays for M. faveolata contained 1,314 coding sequences, of which 43% had functional annotations as determined by homology to known genes.
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response; coral bleaching 5 control and 5 heat-stressed RNA samples were hybridized in a 5-replicate dye-swap design (10 total hyb's).
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response, time course, coral bleaching
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response; coral bleaching