Dataset for manuscript "Microgeographic variation in gene expression plasticity under osmotic stress in wild eastern oyster juveniles (<i>Crassostrea virginica</i>)"

Gene expression plasticity is an essential mechanism of physiological acclimation. In adult eastern oysters, <i>Crassostrea virginica </i>(Gmelin, 1791), transcriptomic responses to experimental osmotic stress differ between oyster bed sources within the estuarine salinity gradient. Here RNA-seq was used to characterize spatial variation in gene expression plasticity in wild oyster spat (juveniles), collected from upper and lower Delaware Bay oyster beds, and reciprocally exposed to moderate and low salinity experimental treatments. Low salinity conditions contribute significantly to mortality in the species and stressful upper bay episodes of extended hypo-salinity are expected to increase in frequency under future climate conditions. The spat collected at moderate salinity (lower bay) sites show more than twice as many differentially expressed transcripts between treatments, relative to their upper bay counterparts – a pattern of spatial variation in gene expression plasticity consistent with previous findings in adults. However, an alternate measure of gene expression plasticity, the log-fold degree of expression difference between treatments, was greater in oysters collected at low salinity (upper bay). Observed spatial differences in gene expression plasticity indicate that early pre- or post-settlement environmental conditions likely generated distinct transcriptome-wide osmotic stress responses between upper and lower bay populations of a single estuary.

基因表达可塑性（gene expression plasticity）是生理驯化的关键机制。针对成年美洲牡蛎（*Crassostrea virginica* (Gmelin, 1791)）的研究表明，在河口盐度梯度下，不同牡蛎床种群来源的个体在实验渗透压胁迫下的转录组响应存在显著差异。本研究采用RNA测序（RNA-seq）技术，对从特拉华湾上游与下游牡蛎床采集的野生牡蛎幼贝（稚贝）的基因表达可塑性空间变异进行表征：这些幼贝被交叉暴露于中等盐度与低盐度的实验处理条件下。低盐度环境对该物种的死亡率具有显著影响，而未来气候情景下，海湾上游出现的持续性低盐度胁迫事件的发生频率预计将进一步升高。采集自中等盐度位点（下游海湾）的幼贝，其不同处理组间的差异表达转录本数量是上游海湾对应个体的两倍以上——这一基因表达可塑性的空间变异模式与此前在成年牡蛎中的研究结果一致。然而，另一种衡量基因表达可塑性的指标，即处理组间基因表达差异的对数折叠变化，在采集自低盐度位点（上游海湾）的幼贝中更高。本研究观测到的基因表达可塑性空间差异表明，在单一河口的上下游海湾种群之间，早期定居前或定居后的环境条件可能塑造了截然不同的全转录组水平渗透压胁迫响应。

搜集汇总

背景与挑战

背景概述

该数据集为研究野生东部牡蛎幼体在盐度胁迫下基因表达可塑性的微观地理变异提供支持，包含来自特拉华湾不同盐度区域（上游和下游）的牡蛎样本在实验性中低盐度处理下的RNA-seq数据。研究发现，不同地理来源的牡蛎在基因表达可塑性上存在显著差异，如下游样本显示更多差异表达转录本，而上游样本在表达差异程度上更高，这反映了早期环境条件对种群转录组应激响应的影响。