Freshwater mussels of the order Unionida are a global conservation concern. Species of this group are strictly freshwater, sessile, slow-growing animals and, extremely sensitive to environmental changes. Human-mediated changes in freshwater habitats are imposing enormous pressure on the survival of freshwater mussels. Although a few flagship species are protected in Europe, other highly imperilled species receive much less attention. Moreover, knowledge about biology, ecology, and evolution and proper conservation assessments of many European species are still sparse. This knowledge gap is further aggravated by the lack of genomic resources available, which are key tools for conservation. Here we present the transcriptome assembly of Unio elongatulus C. Pfeiffer, 1825, one of the least studied European freshwater mussels. Using the individual sequencing outputs from eight physiologically representative mussel tissues, we provide an annotated panel of tissue-specific Relative Gene Expression profiles. These resources are pivotal to studying the species’ biological and ecological features, as well as helping to understand its vulnerability to current and future threats.

Unionida 淡水贻贝是全球保护关注的焦点。该群体的物种严格来说是淡水、固着、生长缓慢的动物，并且对环境变化极其敏感。人类引起的淡水栖息地变化给淡水贻贝的生存带来了巨大压力。尽管一些旗舰物种在欧洲受到保护，但其他高度濒危物种受到的关注要少得多。此外，关于生物学、生态学和进化的知识以及对许多欧洲物种的适当保护评估仍然很少。由于缺乏可用的基因组资源，这种知识差距进一步加剧，而基因组资源是保护的关键工具。在这里，我们展示了Unio elongatulus C. Pfeiffer, 1825的转录组组装，这是研究最少的欧洲淡水贻贝之一。使用来自八个具有生理代表性的贻贝组织的单独测序输出，我们提供了一组带注释的组织特异性相对基因表达谱。这些资源对于研究该物种的生物和生态特征以及帮助了解其面对当前和未来威胁的脆弱性至关重要。