Gurr Samuel J, Trigg Shelly A, Vadopalas Brent, Roberts Steven B, Putnam Hollie M
Department of Biological Sciences, University of Rhode Island, Kingston, Rhode Island, USA.
NOAA Milford Laboratory, NOAA Northeast Fisheries Science Center Milford Laboratory, Milford, Connecticut, USA.
Mol Ecol. 2022 Oct;31(19):5005-5023. doi: 10.1111/mec.16644. Epub 2022 Aug 25.
Sublethal exposure to environmental challenges may enhance ability to cope with chronic or repeated change, a process known as priming. In a previous study, pre-exposure to seawater enriched with pCO improved growth and reduced antioxidant capacity of juvenile Pacific geoduck Panopea generosa clams, suggesting that transcriptional shifts may drive phenotypic modifications post-priming. To this end, juvenile clams were sampled and TagSeq gene expression data were analysed after (i) a 110-day acclimation under ambient (921 μatm, naïve) and moderately elevated pCO (2870 μatm, pre-exposed); then following (ii) a second 7-day exposure to three pCO treatments (ambient: 754 μatm; moderately elevated: 2750 μatm; severely elevated: 4940 μatm), a 7-day return to ambient pCO and a third 7-day exposure to two pCO treatments (ambient: 967 μatm; moderately elevated: 3030 μatm). Pre-exposed geoducks frontloaded genes for stress and apoptosis/innate immune response, homeostatic processes, protein degradation and transcriptional modifiers. Pre-exposed geoducks were also responsive to subsequent encounters, with gene sets enriched for mitochondrial recycling and immune defence under elevated pCO and energy metabolism and biosynthesis under ambient recovery. In contrast, gene sets with higher expression in naïve clams were enriched for fatty-acid degradation and glutathione components, suggesting naïve clams could be depleting endogenous fuels, with unsustainable energetic requirements if changes in carbonate chemistry persist. Collectively, our transcriptomic data indicate that pCO priming during post-larval periods could, via gene expression regulation, enhance robustness in bivalves to environmental change. Such priming approaches may be beneficial for aquaculture, as seafood demand intensifies concurrent with increasing climate change in marine systems.
亚致死剂量的环境挑战暴露可能会增强应对慢性或反复变化的能力，这一过程称为预适应。在之前的一项研究中，预先暴露于富含pCO的海水中可改善幼年太平洋潜泥蛤的生长并降低其抗氧化能力，这表明转录变化可能驱动预适应后的表型改变。为此，对幼年蛤进行采样，并在以下情况下分析TagSeq基因表达数据：(i) 在环境pCO（921μatm，未预暴露）和适度升高的pCO（2870μatm，预暴露）下进行110天的驯化；然后在 (ii) 第二次7天暴露于三种pCO处理（环境：754μatm；适度升高：2750μatm；严重升高：4940μatm）、7天恢复到环境pCO以及第三次7天暴露于两种pCO处理（环境：967μatm；适度升高：3030μatm）之后。预暴露的潜泥蛤预先加载了应激、凋亡/先天免疫反应、稳态过程、蛋白质降解和转录调节因子的基因。预暴露的潜泥蛤对随后的暴露也有反应，在pCO升高时，基因集富集于线粒体循环利用和免疫防御，在环境恢复时富集于能量代谢和生物合成。相比之下，在未预暴露的蛤中高表达的基因集富集于脂肪酸降解和谷胱甘肽成分，这表明未预暴露的蛤可能在消耗内源性燃料，如果碳酸盐化学持续变化，其能量需求将不可持续。总体而言，我们的转录组数据表明，幼体后期的pCO预适应可以通过基因表达调控增强双壳贝类对环境变化的耐受性。随着海洋系统气候变化加剧，海鲜需求增加，这种预适应方法可能对水产养殖有益。
