Background Coral reefs are expected to be severely impacted by rising seawater temperatures associated with climate change. This study used cDNA microarrays to investigate transcriptional effects of thermal stress in embryos of the coral Montastraea faveolata. Embryos were exposed to 27.5C, 29.0C, and 31.5C directly after fertilization. Differences in gene expression were measured after 12 and 48 hours. Results Analysis of differentially expressed genes indicated that increased temperatures may lead to oxidative stress, apoptosis, and a structural reconfiguration of the cytoskeletal network. Metabolic processes were downregulated, and the action of histones and zinc finger-containing proteins may have played a role in the long-term regulation upon heat stress. Conclusions Embryos responded differently depending on exposure time and temperature level. Embryos showed expression of stress-related genes already at a temperature of 29.0C, but seemed to be able to counteract the initial response over time. By contrast, embryos at 31.5C displayed continuous expression of stress genes. The genes that played a role in the response to elevated temperatures consisted of both highly conserved and coral-specific genes. These genes might serve as a basis for research into coral-specific adaptations to stress responses and global climate change. Overall design: 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. We used three technical replicates for each temperature. Common reference samples were labeled with Cy3, temperature 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.
|Date made available
|Aug 31 2012