Toxic effects induced in Lemma minor by an environmentally relevant mixture of uranium and metals: selection of potential uranium biomarker genes

Worldwide anthropogenic activities have caused increased uranium levels beyond naturally occurring concentrations. Under natural conditions, organisms are usually exposed to a mixture of chemicals. The aim of this study is to investigate on Lemna minor the contribution of uranium in the toxicity induced by a uranium/metal mixture in environmental relevant concentrations. Only recently a draft Lemna minor genome was obtained and an RNAseq experiment was conducted on plants exposed to uranium, beta and gamma radiation. This enabled the search for genes that can potentially be used as biomarkers for uranium exposure. Frond number is a less sensitive growth parameter than frond area and biomass. Despite the limited number of genes tested, one gene could be identified with promising features as potential biomarker. The U/metal mixture showed signals for antagonist growth effects compared to the single exposures possibly due to interaction at the level of U/metal uptake.