mRNA-Seq of Lemna minor exposed to different concentrations of the pharmaceutical atorvastatin against untreated control groups. mRNA-Seq of Lemna minor exposed to different concentrations of the pharmaceutical atorvastatin against untreated control groups

In this study, Lemna minor was used to investigate ecotoxic modes-of-action (MoA) at the gene expression level. For this purpose, mRNA sequencing was applied to plant RNA extracted from L. minor exposed to the pharmaceutical atorvastatin in a shortened version of the OECD guideline test No. 221 (OECD TG 221). L. minor is commonly used as a non-target model organism to determine ecotoxicological effects of xenobiotics. Since atorvastatin (and statins in general) are frequently used pharmaceuticals, they can be found in the aquatic environment. In humans, they are used as cholesterol-lowering agents due to their hydroxymethylglutaryl-CoA reductase (HMGR) inhibitory effect. Analogously, in L. minor, atorvastatin can also inhibit the plant’s HMGR, which is involved in phytosterol synthesis. The aim of our study was to determine a molecular fingerprint of the substance in order to identify potential biomarkers for its MoA. Therefore, we applied bioinformatics approaches to functionally annotate the previously unannotated reference genome of L. minor. Our functional annotation pipeline is in principle applicable to any organism with an available reference genome and thus greatly facilitates the identification of gene functions for poorly annotated organisms. The observed effects at the molecular level showed promising results for the development of OMICs as screening methods as well as for the identification of biomarkers for the toxicity of atorvastatin in L. minor.