Species invasions often occur on coasts and estuaries where abiotic conditions vary, e.g. salinity, temperature, runoff etc. Successful establishment and dispersal of non-indigenous species in many such systems are poorly understood, partially since the species tend to show genetic and ecological plasticity at population level towards many abiotic conditions, including salinity tolerance. Plasticity may be driven by shifting expression of heat shock proteins such as Hsp70, which is widely recognized as indicator of physical stress. In this study, we developed a qPCR assay for expression of the hsp70 gene in the invasive round goby ( Neogobius melanostomus ) and tested the expression response of fish collected from a brackish environment in the western Baltic Sea to three different salinities, 0, 10 and 30. hsp70 expression was highest in fresh water, indicating higher stress, and lower at brackish (ambient condition for the sampled population) and oceanic salinities, suggestive of low stress response to salinities above the population’s current distribution. The highest stress in fresh water was surprising since populations in fresh water exist, e.g. large European rivers and Laurentian Great Lakes. The results have implications to predictions for the species’ plasticity potential and possible range expansion of the species into other salinity regimes.

中文翻译：

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通过侵入性圆形虾虎鱼（Neogobius melanostomus）中的 hsp70 表达估计盐度压力：对进一步扩大范围的影响

物种入侵通常发生在非生物条件变化的海岸和河口，例如盐度、温度、径流等。对非本土物种在许多此类系统中的成功建立和扩散知之甚少，部分原因是该物种往往表现出遗传和生态可塑性许多非生物条件，包括耐盐性。可塑性可能是由热休克蛋白（如 Hsp70）的表达转移驱动的，Hsp70 被广泛认为是身体压力的指标。在这项研究中，我们开发了一种 qPCR 检测方法，用于检测侵入性圆形虾虎鱼 ( Neogobius melanostomus ) 中 hsp70 基因的表达，并测试了从波罗的海西部半咸水环境中收集的鱼类对三种不同盐度，0、10 和30. hsp70 表达在淡水中最高，表明压力较高，而在咸水（采样种群的环境条件）和海洋盐度较低，表明对高于种群当前分布的盐度的低应力响应。淡水中的最高压力令人惊讶，因为淡水中存在种群，例如大型欧洲河流和劳伦斯大湖。结果对预测物种的可塑性潜力和物种可能的范围扩展到其他盐度状况具有影响。例如欧洲的大河流和劳伦大湖。结果对预测物种的可塑性潜力和物种可能的范围扩展到其他盐度状况具有影响。例如欧洲的大河流和劳伦大湖。结果对预测物种的可塑性潜力和物种可能的范围扩展到其他盐度状况具有影响。