Rapid Acclimation Ability Mediated by Transcriptome Changes in Reef-Building Corals.
Bottom Line: For long-lived organisms, acclimation likely generates a faster response but is only effective if the rates and limits of acclimation match the dynamics of local environmental variation.This is in addition to a previously observed longer term response, distinguishable by its shift in baseline expression, under nonstressful conditions.Such rapid acclimation may provide some protection for this species of coral against slow onset of warming ocean temperatures.
Affiliation: Department of Biology, Stanford University email@example.com.Show MeSH
Related in: MedlinePlus
Mentions: Heat-stressed and nonstressed branches had dramatically different transcriptional profiles. The result is that the total number of reads that could be mapped to the reference transcriptome was larger for the nonstressed samples (P < 0.01; supplementary fig. S3, Supplementary Material online)—transcriptomes generated from nonstressed branches had an average of 3.02 million reads mapped compared with 2.26 million for stressed samples. Of 28,053 contigs, 22,338 (79.6%) yielded significant results (FDR = 0.05) in a negative binomial test for differential expression during heat stress. The difference in total read count is likely the result of a drastic change in expression across many genes, altering total transcription levels. Since normalization methods assume that most genes are not differentially expressed, a gene-by-gene analysis of heat stress expression is not reliable in this case. We can, however, compare the magnitude of change during heat stress across groups of genes. We, therefore, examine the response to acute heat stress of genes in the two clusters we identified as differentially expressed across acclimation treatments. These broad-scale comparisons show us that cluster 1 is upregulated after heat stress (P < 0.01) compared with a random sample, while cluster 2 is downregulated after heat stress (P < 0.01; fig. 4). The stress response seen in the 29 °C acclimated samples is dampened in coral colonies acclimated to higher temperatures (fig. 5; supplementary fig. S4, Supplementary Material online); the magnitude of expression during heat stress is smaller for samples acclimated to either 31 °C or variable (29–33 °C) temperatures. Upon further investigation, we see that this muted response is not the result of a change in baseline expression, but differential expression after heat stress in individuals acclimated to higher temperatures (supplementary fig. S5, Supplementary Material online).Fig. 4.—
Affiliation: Department of Biology, Stanford University firstname.lastname@example.org.