Rapid evolution of genome‐wide gene expression and plasticity during saline to freshwater invasions by the copepod Eurytemora affinis species complex
Rapid evolution of genome‐wide gene expression and plasticity during saline to freshwater invasions by the copepod Eurytemora affinis species complex
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DOI：
10.1111/mec.15681
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发表时间：
2020-06
影响因子：
4.9
通讯作者：
M. Posavi;D. Gulisija;James B. Munro;Joana C. Silva;C. Lee
中科院分区：
文献类型：
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作者：
M. Posavi;D. Gulisija;James B. Munro;Joana C. Silva;C. Lee
进入淡水栖息地的咸水移民是全球水生生态系统中最具破坏性的入侵者之一。然而，人们对这种栖息地转变背后的进化和生理机制仍然知之甚少。为了探索淡水适应机制并区分对盐度变化的适应性（进化）和适应（塑性）反应，我们检查了在两种不同的常见花园条件（0与15 PSU）下饲养的Eurytemora affinis物种复合体的祖先盐水和衍生淡水种群之间的全基因组基因表达模式。我们发现，基因表达的进化转变（盐水和淡水自交系之间）显示出比对盐度的适应反应（0 vs 15 PSU）更大的变化，并且更广泛。最值得注意的是，有 30-40 个基因显示出跨盐度边界的基因表达进化变化，这些基因与离子转运功能相关，其中无机阳离子跨膜转运形成了最大的基因本体类别。特别令人感兴趣的是钠转运蛋白，即 Na+/H+ 逆向转运蛋白 (NHA) 基因家族，它是最近在动物中发现的。三十个关键的离子调节基因，例如 NHA 旁系同源物 #7，在基因表达中表现出一致的进化和可塑性变化，表明离子转运蛋白功能和可塑性在快速侵入新盐度期间的进化。此外，淡水入侵与淡水种群可塑性降低的演变有关，同样对于相同的关键离子转运蛋白而言，这与适应压力条件后运河化的预测演变一致。我们的结果对于理解水生栖息地中一些最广泛的入侵者扩大范围的进化和生理机制具有重要意义。
Saline migrants into freshwater habitats constitute among the most destructive invaders in aquatic ecosystems throughout the globe. However, the evolutionary and physiological mechanisms underlying such habitat transitions remain poorly understood. To explore the mechanisms of freshwater adaptation and distinguish between adaptive (evolutionary) and acclimatory (plastic) responses to salinity change, we examined genome‐wide patterns of gene expression between ancestral saline and derived freshwater populations of the Eurytemora affinis species complex, reared under two different common‐garden conditions (0 versus 15 PSU). We found that evolutionary shifts in gene expression (between saline and freshwater inbred lines) showed far greater changes and were more widespread than acclimatory responses to salinity (0 versus 15 PSU). Most notably, 30–40 genes showing evolutionary shifts in gene expression across the salinity boundary were associated with ion transport function, with inorganic cation transmembrane transport forming the largest Gene Ontology category. Of particular interest was the sodium transporter, the Na+/H+ antiporter (NHA) gene family, which was discovered in animals relatively recently. Thirty key ion regulatory genes, such as NHA paralogue #7, demonstrated concordant evolutionary and plastic shifts in gene expression, suggesting the evolution of ion transporter function and plasticity during rapid invasions into novel salinities. Moreover, freshwater invasions were associated with the evolution of reduced plasticity in the freshwater population, again for the same key ion transporters, consistent with the predicted evolution of canalization following adaptation to stressful conditions. Our results have important implications for understanding evolutionary and physiological mechanisms of range expansions by some of the most widespread invaders in aquatic habitats.