Biomarkers for monitoring water quality with brown trout

Molecular biomarkers can be used to better understand the effects of environmental pollutants on organisms in both the laboratory and the field. By measuring the gene expression of selected genes, it is possible to detect effects (effect biomarker), that do not directly lead to the death of the organism, but can damage it in the long term, or inform that the organism was exposed to a certain pollutant (exposure biomarker).

In a previous project, biomarker genes selection for brown trout was based on data published in the scientific literature and information on the primary mechanisms of action of relevant pesticides. The level of expression was measured by reverse-transcription quantitative PCR.

In this project, we will use RNA-Seq (high throughput sequencing of the whole transcriptome) to get a more global and deeper information on the genes’ responses when juvenile brown trout are exposed to pesticides or increased water temperature exposure, or infected by a parasite, leading to the proliferative kidney disease. The expression level of genes in brain and liver tissues from juvenile brown trout will be studied after laboratory exposure to (i) a pesticide mixture relevant for Switzerland, (ii) elevated water temperature (15^oC) and (iii) infection with the parasite (PKD). Multiple stressors scenario are also planed. The most relevant genes (e.g. specific response to pesticide, up/down-regulated by temperature stress, etc.) will be part a set of candidate genes to design a GeneChip, that enables a more cost- and time-efficient analysis of the biomarkers. Laboratory and field experiments will be run to validate this promising tool.