In the environmental risk assessment of substances, toxicity to aquatic plants is evaluated using, among other methods, the 7 dayLemna sp. growth inhibition test following the OECD TG 221. So far, the test is not applicable for short-term screening of toxicity, nor does it allow evaluation of toxic modes of action (MoA). The latter is also complicated by the lack of knowledge of gene functions in the test species. Using ecotoxicogenomics, we developed a time-shortened 3 day assay inLemna minor which allows discrimination of ecotoxic MoA. By examining the changes in gene expression induced by low effect concentrations of the pharmaceutical atorvastatin and the herbicide bentazon at the transcriptome and proteome levels, we were able to identify candidate biomarkers for the respective MoA. We developed a homology-based functional annotation pipeline for the reference genome ofL. minor, which allowed overrepresentation analysis of the gene ontologies affected by both test compounds. Genes affected by atorvastatin mainly influenced lipid synthesis and metabolism, whereas the bentazon-responsive genes were mainly involved in light response. Our approach is therefore less time-consuming but sensitive and allows assessment of MoA in L. minor. Using this shortened assay, investigation of expression changes of the identified candidate biomarkers may allow the development of MoA-specific screening approaches in the future.

中文翻译：

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小柠檬生态毒性作用模式的毒物基因组学分析的短期试验

在物质的环境风险评估中，使用 7 天Lemna sp.等方法评估对水生植物的毒性。经济合作与发展组织 TG 221 之后的生长抑制测试。到目前为止，该测试不适用于毒性的短期筛选，也不允许评估毒性作用模式 (MoA)。后者也因缺乏对测试物种基因功能的了解而变得复杂。使用生态毒物基因组学，我们在Lemna minor中开发了一种时间缩短的 3 天检测方法这允许区分生态毒性 MoA。通过检查药物阿托伐他汀和除草剂苯达松在转录组和蛋白质组水平上的低效浓度诱导的基因表达变化，我们能够确定各自 MoA 的候选生物标志物。我们为L. minor的参考基因组开发了一个基于同源性的功能注释管道，它允许对受两种测试化合物影响的基因本体进行过度表示分析。受阿托伐他汀影响的基因主要影响脂质合成和代谢，而苯达松反应基因主要参与光反应。因此，我们的方法耗时较少但敏感，并且允许评估 L.minor 中的MoA. 使用这种缩短的检测方法，研究已识别的候选生物标志物的表达变化可能有助于在未来开发 MoA 特异性筛选方法。