From laboratory to the field: Validating molecular markers of effect in Folsomia candida exposed to a fungicide-based formulation

Under controlled laboratory conditions, toxicity data tend to be less variable than in more realistic in-field studies and responses may thus differ from those in the natural environment, creating uncertainty. The validation of data under environmental conditions is therefore a major asset in environmental risk assessment of chemicals. The present study aimed to validate the mode of action of a commercial fungicide formulation in the soil invertebrate F. candida, under more realistic exposure scenarios (in-field bioassay), by targeting specific molecular biomarkers retrieved from laboratory experiments. Organisms were exposed in soil cores under minimally controlled field conditions for 4 days to a chlorothalonil fungicide dosage causing 75% reduction of reproduction in a previous laboratory experiment (127 mg a.i. kg−1 ) and half this concentration (60 mg a.i. kg−1 ). After exposure, organisms were retrieved and RNA was extracted from each pool of organisms. According to previous laboratorial omics results with the same formulation, ten genes were selected for gene expression analysis by qRT-PCR, corresponding to key genes of affected biological pathways including glutathione metabolism, oxidation-reduction, body morphogenesis, and reproduction. Six of these genes presented a dose-response trend with higher up- or down-regulation with increasing pesticide concentrations. Highly significant correlations between their expression patterns in laboratory and in-field experiments were observed. This work shows that effects of toxicants can be clearly demonstrated in more realistic conditions using validated biomarkers. Our work outlines a set of genes that can be used to assess the early effects of pesticides in a realistic agricultural scenario.

Description

This work was supported by the Portuguese Foundation for Science and Technology (FCT) through the projects UID/MAR/04292/2019, ENVIRONOME (PTDC/AGR-PRO/3496/2012 - POCI-01-0145-FEDER016773), and grants awarded to TS (SFRH/BD/98266/2013), SN (SFRH/BPD/94500/2013), and TNL (SFRH/BPD/110943/2015). Project was also partially funded by the Integrated Programme of SR& TD “SmartBioR” (reference Centro-01-0145-FEDER-000018) cofunded by Centro 2020 program, Portugal2020, European Union, through the European Regional Development Fund. DR was also supported by EU FP7 Sustainable Nanotechnologies Project (SUN, contract number 604305). The authors also acknowledge Luís Alves and Sofia Silva for the assistance in the experimental procedure.

Keywords

Biomarkers Chlorothalonil Collembola In situ validation Fungicides qPCR

URI

http://hdl.handle.net/10400.8/4208

Citation

Simões, T., Novais, S.C., Natal-da-Luz, T., Renaud, M., Leston, S., Ramos, F., Römbke, J., Roelofs, D., van Straalen, N.M., Sousa, J.P., Lemos, M.F.L. (2019). From laboratory to the field: validating molecular markers of effect in Folsomia candida exposed to a fungicide-based formulation. Environment International 127, 522-530.