Small ocean temperature increases elicit stage-dependent changes in DNA methylation and gene expression in a fish, the European sea bass

Abstract

In natural fish populations, temperature increases can result in shifts in important phenotypic traits. DNA methylation is an epigenetic mechanism mediating phenotypic changes. However, whether temperature increases of the magnitude predicted by the latest global warming models can affect DNA methylation is unknown. Here, we exposed European sea bass to moderate temperature increases in different periods within the first two months of age. We show that increases of even 2 °C in larvae significantly changed global DNA methylation and the expression of ecologically-relevant genes related to DNA methylation, stress response, muscle and organ formation, while 4 °C had no effect on juveniles. Furthermore, DNA methylation changes were more marked in larvae previously acclimated to a different temperature. The expression of most genes was also affected by temperature in the larvae but not in juveniles. In conclusion, this work constitutes the first study of DNA methylation in fish showing that temperature increases of the magnitude predicted by the latest global warming models result in stage-dependent alterations in global DNA methylation and gene expression levels. This study, therefore, provides insights on the possible consequences of climate change in fish mediated by genome-wide epigenetic modifications.

Ovarian transcriptomic signatures of zebrafish females resistant to different environmental perturbations

“…Most of these were related to cellular and metabolic processes, suggesting that the biosynthesis of some compounds were affected. In particular, we found a downregulation of the methylation GO term which is known to be involved in sex differentiation in fish (Anastasiadi, Díaz, & Piferrer, 2017;Navarro-Martín et al, 2011). This GO term included the RNA (guanine-7-) methyltransferase (rnmt), histamine N-methyltransferase (hnmt) and suv420h2 genes, which are three methyltransferases that regulate the epigenome of developing organs and of the germline (Anway, Rekow, & Skinner, 2008) the dysfunction of which is involved in multiple human diseases (García-Martín et al, 2010).…”

Immune genes, IL1β and Casp9, show sexual dimorphic methylation patterns in zebrafish gonads

“…In fish gonads, the first study showing the interaction between epigenetics and sexual development was published eight years ago in European sea bass, Dicentrarchus labrax, showing that methylation of the gonadal aromatase (cyp19a1a) promoter was altered in the ovaries of adult females previously exposed to high temperatures during the early stages of development (Navarro-Martin et al, 2011). Since then, other studies, including this fish species (Anastasiadi et al, 2017;Anastasiadi et al, 2018b) have evidenced the important role of epigenetic mechanisms in the gonads. This is the case, for example, in half-smooth tongue sole, Cynoglossus semilaevis (Shao et al, 2014), Nile tilapia, Oreochromis niloticus, (Wang et al, 2017) or barramundi, Lates calcarifer (Domingos et al, 2018), among others (reviewed in Piferrer et al (2019) all of them revealing the importance of the methylation processes in reproduction-related genes in the ovaries or in the testes and thereby underlining sexual dimorphic epigenetic patterns.…”

Climate Change Impacts on Seagrass Meadows and Macroalgal Forests: An Integrative Perspective on Acclimation and Adaptation Potential

“…One pioneering study on an Antarctic polychaete showed that a net increase in DNA methylation contributed to acclimation to warmer temperatures (−1.5 • vs. +4 • C), by regulating energy metabolism (Marsh and Pasqualone, 2014). In the European sea bass, a temperature increase of 2 • C was shown to change global DNA methylation in larval but not in juvenile stages (Anastasiadi et al, 2017). In the scleractinian coral Pocillopora damicornis, DNA methylation levels increased globally in response to increased pCO 2 levels (from ambient pH 7.9-7.65 to low pH 7.6-7.35) (Putnam et al, 2016).…”