Synergistic Effects of Temperature and Salinity on the Gene Expression and Physiology of Crassostrea virginica
Synergistic Effects of Temperature and Salinity on the Gene Expression and Physiology of Crassostrea virginica
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DOI：
10.1093/icb/icz035
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发表时间：
2019-08-01
影响因子：
2.6
通讯作者：
Kelly, M. W.
中科院分区：
文献类型：
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作者：
Jones, H. R.;Johnson, K. M.;Kelly, M. W.
东部牡蛎，Crassostrea virginica，形成珊瑚礁，为周围的生态系统提供关键服务。这些珊瑚礁面临气候变化的风险，部分原因是降雨模式的改变可能会放大当地盐度的波动，影响牡蛎的招募，生存和生长。与其他海洋生物一样，水温升高可能与盐度的变化相互作用，协同影响牡蛎的生理学。在这项研究中，我们使用比较转录组学，生理测量和实地评估，以调查什么表型变化C。virginica用来科普墨西哥湾的温度和盐度压力。牡蛎从一个历史上低盐度的网站（姐妹湖，洛杉矶）暴露于完全交叉的温度（20摄氏度和30摄氏度）和盐度（25，15，和7 PSU）的治疗。利用牡蛎鳃组织的比较转录组学，我们确定了更多的差异表达的基因（DE）在低盐度在温暖的温度。功能富集分析表明，低重叠的基因DE之间的热应力相比，低渗应力和确定富集与细胞粘附，跨膜转运，和微管为基础的过程的基因本体。实验还表明，牡蛎在温度升高和盐度降低的情况下改变了生理机能，在20摄氏度至30摄氏度之间，呼吸速率显著增加。然而，尽管有更高的能量需求，牡蛎并没有增加它们的摄食率。为了研究原位种群之间的转录差异，我们收集了来自路易斯安那湾沿岸三个地点和两个时间点的鳃组织，并使用定量PCR来测量七个靶基因的表达水平。我们发现，在我们的低盐度的网站和采样时间点的渗透压转运，氧化应激介导，细胞凋亡和蛋白质合成的基因功能的上调。总之，牡蛎改变了他们的表型更多的低盐度，在较高的温度下，证明了实验室暴露期间，增加呼吸（高能量需求），并在原位差异表达的DE基因的数量更高，季节和位置。低渗胁迫和温度升高的协同效应表明，气候变化将加剧低盐度暴露对东部牡蛎的负面影响。
The eastern oyster, Crassostrea virginica, forms reefs that provide critical services to the surrounding ecosystem. These reefs are at risk from climate change, in part because altered rainfall patterns may amplify local fluctuations in salinity, impacting oyster recruitment, survival, and growth. As in other marine organisms, warming water temperatures might interact with these changes in salinity to synergistically influence oyster physiology. In this study, we used comparative transcriptomics, measurements of physiology, and a field assessment to investigate what phenotypic changes C. virginica uses to cope with combined temperature and salinity stress in the Gulf of Mexico. Oysters from a historically low salinity site (Sister Lake, LA) were exposed to fully crossed temperature (20 degrees C and 30 degrees C) and salinity (25, 15, and 7 PSU) treatments. Using comparative transcriptomics on oyster gill tissue, we identified a greater number of genes that were differentially expressed (DE) in response to low salinity at warmer temperatures. Functional enrichment analysis showed low overlap between genes DE in response to thermal stress compared with hypoosmotic stress and identified enrichment for gene ontologies associated with cell adhesion, transmembrane transport, and microtubule-based process. Experiments also showed that oysters changed their physiology at elevated temperatures and lowered salinity, with significantly increased respiration rates between 20 degrees C and 30 degrees C. However, despite the higher energetic demands, oysters did not increase their feeding rate. To investigate transcriptional differences between populations in situ, we collected gill tissue from three locations and two time points across the Louisiana Gulf coast and used quantitative PCR to measure the expression levels of seven target genes. We found an upregulation of genes that function in osmolyte transport, oxidative stress mediation, apoptosis, and protein synthesis at our low salinity site and sampling time point. In summary, oysters altered their phenotype more in response to low salinity at higher temperatures as evidenced by a higher number of DE genes during laboratory exposure, increased respiration (higher energetic demands), and in situ differential expression by season and location. These synergistic effects of hypoosmotic stress and increased temperature suggest that climate change will exacerbate the negative effects of low salinity exposure on eastern oysters.