Data_Sheet_1_Synergistic Effects of Thermal Stress and Estuarine Discharge on Transcriptomic Variation of Montastraea cavernosa Corals in Southeast Florida.pdf

Coral reefs at the northern extent of Florida’s coral reef tract are exposed to many localized anthropogenic influences including controlled freshwater discharges, runoff, upwelling, and seasonal environmental variability. To better understand coral responses to sublethal stressors in nearshore environments, we conducted complementary experiments to assess the impacts of estuarine runoff and temperature stress on local populations of the scleractinian coral species, Montastraea cavernosa, using Tag-Seq global gene expression profiling. In an in situ time series experiment, fate-tracked colonies were sampled during periods of relatively low and high estuarine discharge over 4 years to investigate temporal trends in transcriptional patterns and to identify if coral stress indicators were regulated through time. There was significant transcriptomic variation through time, but patterns did not appear to be attributed to distance from nearby estuarine tidal flux. In an ex situ factorial experiment, clonal replicates of coral genotypes were exposed to temperature (25°C and 30°C) and water (offshore and estuarine discharge, representing typical oceanic conditions and episodic discharge conditions, respectively) treatments to quantify the potential individual and synergistic effects of sublethal stress on coral and algal gene expression. Comparative analyses suggested that corals and their algal symbionts were more responsive to thermal stress than to estuarine discharge, although there was evidence of a synergistic relationship between the two stressors. Strong genotype effects also demonstrated that transcriptomic responses to thermal stress were largely based on coral genotype, indicating the potential for stress resilience among certain members of coral populations from southeast Florida.

佛罗里达珊瑚礁带最北端的珊瑚礁，受到诸多局地人为活动影响，包括受控淡水排放、地表径流、上升流以及季节性环境波动。
为深入了解近岸环境中珊瑚对亚致死胁迫因子（sublethal stressors）的响应，我们开展了互补性实验，借助标签测序（Tag-Seq）全局基因表达谱分析技术，评估河口径流与温度胁迫对本地石珊瑚（scleractinian coral）物种洞穴星珊瑚（Montastraea cavernosa）种群的影响。
在原位（in situ）时间序列实验中，我们在4年周期内的河口径流高低期分别采样经命运追踪标记的珊瑚群体，以探究转录模式的时间动态，并解析珊瑚胁迫指示因子是否随时间受到调控。
尽管随时间推移存在显著的转录组差异，但这些模式似乎与距附近河口潮汐通量的距离无关。
在异位（ex situ）析因实验中，我们将珊瑚基因型的克隆重复株暴露于温度（25℃与30℃）和水体（近海与河口径流，分别代表典型海洋环境与间歇性排放环境）两种处理条件下，以量化亚致死胁迫对珊瑚及其藻类共生体基因表达的潜在单独效应与协同效应。
比较分析结果显示，相较于河口径流胁迫，珊瑚及其藻类共生体对温度胁迫的响应更为强烈，不过也有证据表明两种胁迫因子之间存在协同关系。
显著的基因型效应同样表明，珊瑚对温度胁迫的转录组响应在很大程度上取决于珊瑚基因型，这预示着佛罗里达东南部珊瑚种群中的部分个体具备胁迫抗性潜力。