Deciphering the toxicological impact of sublethal ethion exposed Drosophila melanogaster using classical and transcriptomics approaches.

Ethion insecticide is known for its neurotoxicity and due to its extensive usage, non- target species may suffer along with the targeted ones. Thus, its detrimental effects on non-target species need to be explored in depth. The present study aims to assess the ethion toxicity in non-target model Drosophila melanogaster using classical and molecular approaches. The two sublethal concentrations 1.25 and 1.88 ppm were selected based on the LC50 value and were used throughout the experiments. The detrimental effect of ethion on various life history traits increased with higher concentration. The phenotypic observations s evidenced deformities in egg, larvae and adult. The histological analysis revealed larval brain degeneration, loss of eye- imaginal disk nuclear features and extensive tissue damage in gut and Malpighian tubules. The preliminary RNAseq data analysis revealed that the upregulated differentially expressed genes (DEGs) in response to ethion were mostly associated with growth and development (TwdlM, TwdlL and Eip78C etc.), neurological behavior (ap, inaD, Galphaq, Rim, ple, ddc etc.), reproduction (Cp15, Cp16, Cp7Fa, Cp7Fb, dec, CG1077 etc.). Moreover, the downregulated DEGs are belong to the class of Mitochondrial Ribosomal Protein (MRP) gene family which regulate growth through mitochondrial translation and transcription. The top 25 hub genes among DEGs were found to have human orthologues, which are used as candidate genes in studying various human diseases. Thus, the study highlights attention to the concerning ecotoxicity and possible health hazards associated with insecticide usage especially to non-targets including humans.