Molecular characterization of C. elegans response to Glyphosate

KRONBERG, M. FLORENCIA; CLAVIJO, ARACELI; MOYA, ALDANA; PAGANO, EDUARDO; MUNARRIZ, ELIANA

Natal

Congreso; IX Congress of Toxicology in Developing Countries; 2015

International Union of Toxicology and the Brazilian Society of Toxicology

Introduction:After maize, Soybean constitutes the second larger crop around the world and almost 80% of this crop worldwide is genetically modified. The glyphosate resistant soybean genotype is the most common transgenic variant cultivated and in consequence, glyphosate is one of the world larger pesticides applied to crops.Most of the current literature on the toxicity of glyphosate comes from classical toxicologyapproaches, which focus its endpoint in viability, reproduction and fecundity but little information is known about the intracellular molecular mechanism of glyphosate toxicity in not target species. The nematode Caenorhabditiselegansis emerging as a valuable in vivo model, for both mechanistic and environmental toxicology, to predict outcomes in higher eukaryotes toxicity.Objective:The aim of this study is to establish the effect of glyphosate on gene expression of oxidative stress pathways in C. elegansin order to identify candidate genes to evaluate molecular changes in environmental water samples contaminated with glyphosate.Materials and Methods:C. eleganswas originally obtainedfrom the Caenorhabditis Genetics Center (CGC) and maintained as stocks.The nematode bioassay was carried out, with a few modifications, according to standard methods (ISO, 2010). Real time PRC and catalase assay were performed with standards protocols.Results and Discussion:C. elegans growth as well as reproduction and fertility were inhibited by treatment with commercial formulate glyphosate (Glyphosate F) in a dose-dependent manner (EC50 values:1,1; 0,8; 0,8mg/ml respectively). Upon treatment with Glyphosate F we observed an increase in the Reactive Oxygen Species (ROS) formation (similar to levels induced by Paraquat), revealinga modification in the redox balance of the organism induced by this pesticide. C. elegans has different molecular mechanisms that can be induced in response to increasing ROS concentration. To identify which pathways were predominantly upregulated upon exposure to glyphosate F we measure changes in the expression levels of different detoxifying enzymes. We observed a specific induction of Catalase genes (ctl-1, ctl-3 but not ctl-2) and concomitantly increase in the catalase activity.Conclusions:In this work we analysed the C. elegans response to commercial formulate glyphosate treatments. We established the EC50 for growth, reproduction and fertility. In addition we observed significant increase in the catalase genes expression and also their activity upon glyphosate F treatment in C. elegans. At the moment we are performing experiments with environmental water samples containing glyphosate in order to establish glyphosate contamination detecting protocols based on catalase activity detection. Acknowledgments:This study has received the financial support from the FONCyT-MINCyT and MINAGRI, grants: PID 0032/2011 and PRH-PICT0018/2011.