Transcriptional profiling induced by pesticides employed in organic agriculture in a wild population of Chironomus riparius under laboratory conditions Valeria Lencioni a, ⁎, Valentina Grazioli a,b , Bruno Rossaro b , Paola Bernabò a,c, ⁎ a Section of Invertebrate Zoology and Hydrobiology, MUSE-Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy b Department of Agrifood and Urban Systems Protection and Biodiversity Enhancement (DiPSA), University of Milan, Via Celoria 1, 20133 Milano, Italy c CNR-Institute of Biophysics, Via Sommarive 18, 38123 Povo (Trento), Italy HIGHLIGHTS • Pesticides allowed in organic agricul- ture (Cu, neem) are toxic for aquatic wildlife. • Cu is more toxic (24 h- LC 50 = 26 mg l −1 ) than azadirachtin (24 h-LC 50 = 1 mg l −1 ). • Wild C. riparius survive expected envi- ronmental concentrations but in a stress state. • Hsp70, hsc70, hsp40, hsp10, cyP450 are responsive even at sub-lethal concen- trations. • Hsps and cyP450 genes are sensitive biomarkers of freshwater monitoring. GRAPHICAL ABSTRACT abstract article info Article history: Received 18 January 2016 Received in revised form 10 March 2016 Accepted 10 March 2016 Available online xxxx Editor: D. Barcelo Copper (Cu) and azadirachtin (AZA-A + B) are pesticides allowed in organic agriculture whose environmental risk and toxicity for aquatic wildlife is only partially known. Reverse Transcription Polymerase Chain Reaction was used to assess the molecular effect of acute and short-term exposure (3, 24 h) of Cu (0.01, 0.05, 1, 10, 25 mg l −1 ) and AZA-A + B (0.2, 0.3, 0.4, 0.5, 1 mg l −1 ) on the expression of five candidate genes (hsp70, hsc70, hsp40, hsp10 and cyP450) in a non-target species, Chironomus riparius. Fourth-instar larvae were collected from a mountain stream polluted by agricultural land run-off. All genes were responsive to both pesticides but each gene had a specific response to the different experimental concentrations and exposure times. A few simi- larities in transcriptional profiling were observed, such as a linear concentration-dependent response of hsp70 after 24 h of exposure (at ≥1 mg l −1 of Cu and ≥0.2 mg l −1 of AZA-A + B) and an up-regulation regardless of the concentration of hsc70 after 24 h of exposure (at ≥0 mg l −1 of Cu and ≥0.2 mg l −1 of AZA-A + B and the up-regulation of hsp70 after 3 h of exposure at ~LC 50 (Cu-LC 50 = 26.1 ± 2.5 mg l −1 , AZA-A + B-LC 50 = 1.1 ± 0.2 mg l −1 ). According to the results, hsp40, hsp10 and cyP450 may be defined as pesticide-dependent (i.e., hsp40 and hsp10 seemed to responded mainly to AZA-A + B and cyP450 to Cu), while hsc70 as time- Keywords: Heat shock proteins Cytochrome P-450 Copper Azadirachtin Biomarkers Freshwater monitoring Science of the Total Environment 557–558 (2016) 183–191 ⁎ Co-corresponding authors. Correspondence to: V. Lencioni, Section of Invertebrate Zoology and Hydrobiology, MUSE-Museo delle Scienze, Corso del Lavoro e della Scienza 3, 38123 Trento, Italy. E-mail addresses: valeria.lencioni@muse.it (V. Lencioni), paola.bernabo@gmail.com (P. Bernabò). http://dx.doi.org/10.1016/j.scitotenv.2016.03.062 0048-9697/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv