Molecular characterization of C. elegans response to Glyphosate

KRONBERG M.F.; CLAVIJO A.; MOYA A.; PAGANO E.A.; MUNARRIZ E.

Natal

Congreso; 9th Congress of Toxicology in Developing Countries and 19th Brazilian Toxicology Congress; 2015

Brazilian Toxicology Society

Introduction: After maize, Soybean constitutes the second larger crop around the world andalmost 80% of this crop worldwide is genetically modified. The glyphosate resistant soybeangenotype is the most common transgenic variant cultivated and in consequence, glyphosate isone 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 informationis known about the intracellular molecular mechanism of glyphosate toxicity in not targetspecies.The nematode Caenorhabditis elegans is emerging as a valuable in vivo model, for bothmechanistic 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 ofoxidative stress pathways in C. elegans in order to identify candidate genes to evaluatemolecular changes in environmental water samples contaminated with glyphosate.Materials and Methods: C. elegans was originally obtained from the Caenorhabditis GeneticsCenter (CGC) and maintained as stocks. The nematode bioassay was carried out, with a fewmodifications, according to standard methods (ISO, 2010). Real time PRC and catalase assaywere performed with standards protocols.Results and Discussion: C. elegans growth as well as reproduction and fertility were inhibitedby treatment with commercial formulate glyphosate (Glyphosate F) in a dose-dependent manner(EC 50 values: 1,1; 0,8; 0,8 mg/ml respectively). Upon treatment with Glyphosate F we observedan increase in the Reactive Oxygen Species (ROS) formation (similar to levels induced byParaquat), revealing a modification in the redox balance of the organism induced by thispesticide.C. elegans has different molecular mechanisms that can be induced in response to increasingROS concentration. To identify which pathways were predominantly upregulated upon exposureto 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 concomitantlyincrease in the catalase activity.Conclusions: In this work we analysed the C. elegans response to commercial formulateglyphosate treatments. We established the EC 50 for growth, reproduction and fertility. In additionwe observed significant increase in the catalase genes expression and also their activity uponglyphosate F treatment in C. elegans. At the moment we are performing experiments withenvironmental water samples containing glyphosate in order to establish glyphosatecontamination detecting protocols based on catalase activity detection.Acknowledgments: This study has received the financial support from the FONCyT-MINCyT andMINAGRI, grants: PID 0032/2011 and PRH-PICT0018/2011.