Compartment‐specific transcriptomics in a reef‐building coral exposed to elevated temperatures

Abstract

Although rising ocean temperatures threaten scleractinian corals and the reefs they construct, certain reef corals can acclimate to elevated temperatures to which they are rarely exposed in situ. Specimens of the model Indo-Pacific reef coral Pocillopora damicornis collected from upwelling reefs of Southern Taiwan were previously found to have survived a 36-week exposure to 30°C, a temperature they encounter infrequently and one that can elicit the breakdown of the coral–dinoflagellate (genus Symbiodinium) endosymbiosis in many corals of the Pacific Ocean. To gain insight into the subcellular pathways utilized by both the coral hosts and their mutualistic Symbiodinium populations to acclimate to this temperature, mRNAs from both control (27°C) and high (30°C)-temperature samples were sequenced on an Illumina platform and assembled into a 236 435-contig transcriptome. These P. damicornis specimens were found to be ∼60% anthozoan and 40% microbe (Symbiodinium, other eukaryotic microbes, and bacteria), from an mRNA-perspective. Furthermore, a significantly higher proportion of genes from the Symbiodinium compartment were differentially expressed after two weeks of exposure. Specifically, at elevated temperatures, Symbiodinium populations residing within the coral gastrodermal tissues were more likely to up-regulate the expression of genes encoding proteins involved in metabolism than their coral hosts. Collectively, these transcriptome-scale data suggest that the two members of this endosymbiosis have distinct strategies for acclimating to elevated temperatures that are expected to characterize many of Earth's coral reefs in the coming decades.

Transcriptomic Resilience of the Montipora digitata Holobiont to Low pH

“…Our findings in the long-term response are similar to those of a previous investigation on the response of another adult scleractinian (Acropora millepora) to a 37-days exposure to low pH (elevated pCO 2 ) that reported absence of change in the expression of target genes associated with calcification and metabolism (Rocker et al, 2015). In agreement with this, previous studies suggest that temperature stress has a greater impact in gene expression of corals than pH (Mayfield et al, 2014;Davies et al, 2016), although resilience to stress conditions varies from one species to another (Loya et al, 2001), and even among populations of the same coral species occurring in habitats with different local conditions (Poli et al, 2017).…”

Trade‐off between taxon diversity and functional diversity in European lake ecosystems

“…; Mayfield et al . ), genes and pathways involved in primary metabolism were dominant in the mRNA libraries. The dominant metabolic pathways in terms of the fraction of expressed sequences in the cDNA libraries were oxidative phosphorylation, photosynthesis and the TCA cycle.…”

Short-Term Thermal Acclimation Modifies the Metabolic Condition of the Coral Holobiont

“…Nothing is known about how the host regulates the supply of nitrate, nor its response to thermal stress. Previous studies that monitored the gene expression of nitrate-transporter 2 (nrt2) in Symbiodinium C under different thermal regimes and in different host species found that temperature had little impact on nrt2 expression (Mayfield et al, 2013a(Mayfield et al, ,b, 2014, but no studies have examined the activity of nitrate reductase of in hospite Symbiodinium under thermal stress.…”