Looking for biomarkers of Hg exposure by transcriptome analysis in the aquatic plant Elodea nuttallii

Recently developed genomics tools have a promising potential to identify early biomarkers of exposure to toxicants. In the present work we used transcriptome analysis (RNA-seq) of Elodea nuttallii -an invasive rooted macrophyte that is able to accumulate large amounts of metals- to identify biomarkers of Hg exposure. RNA-seq allowed identification of genes affected by Hg exposure and also unraveled plant response to the toxic metal: a change in energy/reserve metabolism caused by the inhibition of photosynthesis, and an adaptation of homeostasis networks to control accumulation of Hg. Data were validated by RT-qPCR and selected genes were further tested as biomarkers. Samples exposed in the field and to natural contaminated sediments clustered well with samples exposed to low metal concentrations under laboratory conditions. Our data suggest that this plant and/or this approach could be useful to develop new tests for water and sediment quality assessment.