Wellband Kyle W, Heath Daniel D
Great Lakes Institute for Environmental Research University of Windsor Windsor ON Canada.
Department of Biological Sciences University of Windsor Windsor ON Canada.
Evol Appl. 2017 Apr 25;10(6):563-576. doi: 10.1111/eva.12463. eCollection 2017 Jul.
Phenotypic plasticity buffers organisms from environmental change and is hypothesized to aid the initial establishment of nonindigenous species in novel environments and postestablishment range expansion. The genetic mechanisms that underpin phenotypically plastic traits are generally poorly characterized; however, there is strong evidence that modulation of gene transcription is an important component of these responses. Here, we use RNA sequencing to examine the transcriptional basis of temperature tolerance for round and tubenose goby, two nonindigenous fish species that differ dramatically in the extent of their Great Lakes invasions despite similar invasion dates. We used generalized linear models of read count data to compare gene transcription responses of organisms exposed to increased and decreased water temperature from those at ambient conditions. We identify greater response in the magnitude of transcriptional changes for the more successful round goby compared with the less successful tubenose goby. Round goby transcriptional responses reflect alteration of biological function consistent with adaptive responses to maintain or regain homeostatic function in other species. In contrast, tubenose goby transcription patterns indicate a response to stressful conditions, but the pattern of change in biological functions does not match those expected for a return to homeostatic status. Transcriptional plasticity plays an important role in the acute thermal tolerance for these species; however, the impaired response to stress we demonstrate in the tubenose goby may contribute to their limited invasion success relative to the round goby. Transcriptional profiling allows the simultaneous assessment of the magnitude of transcriptional response as well as the biological functions involved in the response to environmental stress and is thus a valuable approach for evaluating invasion potential.
表型可塑性可保护生物体免受环境变化影响，据推测有助于非本土物种在新环境中初步定殖以及定殖后的范围扩张。支撑表型可塑性性状的遗传机制通常特征不明；然而，有强有力的证据表明基因转录调控是这些反应的一个重要组成部分。在此，我们使用RNA测序来研究圆口虾虎鱼和管鼻虾虎鱼耐温性的转录基础，这两种非本土鱼类尽管入侵时间相近，但在五大湖的入侵程度上却有显著差异。我们使用读取计数数据的广义线性模型，将暴露于水温升高和降低条件下的生物体的基因转录反应与处于环境条件下的生物体进行比较。我们发现，与不太成功的管鼻虾虎鱼相比，更成功的圆口虾虎鱼在转录变化幅度上有更大的反应。圆口虾虎鱼的转录反应反映了生物功能的改变，这与其他物种为维持或恢复稳态功能的适应性反应一致。相比之下，管鼻虾虎鱼的转录模式表明其对压力条件有反应，但生物功能的变化模式与恢复稳态状态预期的模式不匹配。转录可塑性在这些物种的急性热耐受性中起重要作用；然而，我们在管鼻虾虎鱼中证明的对应激的受损反应可能导致其相对于圆口虾虎鱼的入侵成功率有限。转录谱分析允许同时评估转录反应的幅度以及对环境应激反应中涉及的生物功能，因此是评估入侵潜力的一种有价值的方法。
