Abstract

Increased carbon dioxide in the atmosphere and its absorption across the ocean surface will alter natural vari-ations in pH and temperature levels, occurring in coastal upwelling ecosystems. The scallop Argopecten purpur-atus, one of the most economically important species farmed in northern Chile, has been shown to be vulnerable to these environmental drivers. However, the regulatory responses at the gene-level of scallops to these climate stressors remain almost unknown. Consequently, we used an orthogonal experimental design and RNAseq approach to analyze the acute effects of variability in pH and temperature on gene expression in the muscle tissue of A. purpuratus. In respect to control conditions (pH similar to 8.0/ 14 degrees C), the influence of low pH (similar to 7.7) and tem-perature (14 degrees C) induced the activation of several genes associated with apoptotic signaling pathways and protein localization to plasma membrane. Elevated temperature (18 degrees C) and pH (similar to 8.0) conditions increased the expression of transcripts associated with the activation of muscle contraction, regulation, and sarcomere orga-nization effects on muscle tissue. In scallops exposed to low pH and elevated temperature, the genes expressed were differentially associated with the oxidation-reduction process, signal translation, and positive regulation of GTPase activity. These results indicated that the differentially expressed genes under the experimental conditions tested are mainly related to the mitigation of cellular damage and homeostasis control. Our results add knowledge about the function of the adductor muscle in response to stressors in scallops. Furthermore, these results could help in the identification of molecular biomarkers of stress necessary to be integrated into the aquaculture programs for the mitigation of climate change.