Comparative toxicity evaluation of acephate and chlorantraniliprole on drosophila melanogaster Meigen 1830 through transcriptomics and wing geometric morphometrics

Abstract

Pesticides are a necessary component of contemporary farming methods and are often applied to manage pests to increase agricultural yield. Pesticides are regularly used for pest control in agriculture. Therefore, the hazards of using these chemicals outweigh their benefits, and residues of these substances are frequently detected in food products and the environment. The non-selective and ignorant usage of pesticides causes harmful effects on non-target organisms. The present study investigated the non-target effects of two pesticides, acephate and chlorantraniliprole, on the model organism Drosophila melanogaster. Acephate and chlorantraniliprole are two commonly used pesticides in organophosphate and anthranilic diamide groups, respectively. These two chemicals have different modes of action. Acephate has anti cholinesterase activity and chlorantraniliprole acts on insect ryanodine receptors. Sub-lethal exposure to acephate and chlorantraniliprole elicited a wide range of adverse effects on lifecycle parameters like hatchability, pupation, emergence, and stabilised body weight of the adult flies. The hatchability percentage gives a clear picture regarding early sub-lethal toxic effects. Our study revealed a concentration-dependent decrease in hatchability in the treated group. Acephate and chlorantraniliprole significantly impaired the entire organismal growth and early development. The intoxicated organism's pupation, emergence, survival rate and weight showed sound differences. This is a promising toxicological index for evaluating the overall life process. Early embryonic studies revealed the effects of both pesticides qualitatively and quantitatively. Our study used RNA-seq technology (transcriptomics) to investigate the toxic effects of sub- lethal concentrations of acephate and chlorantraniliprole in D. melanogaster. We focused on the unique effects of each pesticide, which were directly linked to their mode of action. Both pesticides significantly altered various pathways and genes crucial for pesticide resistance and immunological response. In the acephate-treated group, 2,031 genes were up-regulated, whereas 1812 genes were down-regulated. Compared to the control group, 1369 genes were up-regulated, and 773 were down-regulated in the chlorantraniliprole-treated group. Our findings suggest that sublethal acephate and chlorantraniliprole exposures can cause up- or down-regulation of P450s, ESTs, GSTs, UGTs, and ABC transporters, which are crucial for detoxification. These findings are particularly important for understanding the whole range of detoxification-related gene activities in D. melanogaster, making a significant scientificcontribution to the field. The third chapter evaluated the acephate and chlorantraniliprole-induced morphological alterations in the wings of D. melanogasterand also transcriptomic validation of genes responsible for wing development. The geometric morphometric (GMM) tool was used to detect fine-scale changes in wing size and shape. Concentration-dependent changes in wing shape were exhibited in both the pesticide-treated group, and these changes were independent of the sex of the organisms and validated by different multivariate analyses. The degree of shape variations differed between acephate and chlorantraniliprole treatments, which is strictly due to the different modes of action of the two pesticides. Pesticide-induced stress leads to changes in the functional integrity of the wing, with the clear separation of proximal- distal wing modules observed in pesticide-treated groups. Transcriptome analysis reveals the differential expression of genes controlling wing vein development, wing development, and other significant genes involved in shaping the wing and regulating wing function in D. melanogaster. Our study's key findings concluded that sub-lethal concentrations of both pesticides significantly altered the normal life cycle of D. melanogaster and inhibited the expression of immunological genes, heat shock proteins, and resistance genes in a non-targeted insect species. We recommend that the sub-lethal concentrations of acephate and chlorantraniliprole significantly affect the immune and resistance mechanisms of non-targeted organisms. We also highlighted the potential of our study's findings to enhance the pesticide safety assessment process. By combining Transcriptomics and GMM analysis with toxicity studies, researchers can identify potential toxicity liabilities early and move forward with only those chemicals that have both efficacy at the target and a low potential for toxicity in the non- target population. We also emphasised the importance of advanced studies, such as proteomics and metabolomics, in elucidating detoxification pathways, thereby facilitating the development of scientific strategies to protect non-target species from xenobiotics.