Investigating DEGs in developing insecticide resistance: Evidence of RpL40 and RpL27A inducing ubiquitin–PINK1-Parkin-dependent mitophagy pathway

Ethion (ET), an organophosphate (OP) insecticide acts by inhibiting acetylcholinesterase (AChE) leading to neurotoxicity and oxidative stress. However, its excessive and inappropriate use in agriculture and healthcare has resulted resistance in target-pest species and become harmful for non-target organisms. In this study, we investigated the development of ethion insecticide resistance in Drosophila melanogaster through biological and transcriptomic analysis and explored the molecular mechanisms that drive this adaptation process. Flies were exposed to two sublethal concentrations 1.25 ppm and 1.88 ppm of ethion for ten generations and F₁ and F₁₀ flies were analysed for the generational and transgenerational effect of ethion using biological parameters. Transcriptomic analysis was performed with the same generation flies (F₁ and F₁₀) to understand the differentially expressed genes (DEGs) and their involvement in various processes such as cell morphogenesis, transcription regulation, locomotor activities, metamorphosis, sensory and growth and visual system development, metabolism, catalytic and protein kinase activity etc. The comparison was made among two combinations of groups i.e., ethion F₁ treated (ETF₁) vs ethion-treated resistant (ETR) and control vs ETR. In control vs ETR group, heat shock ubiquitous DEGs were found to be upregulated which help organisms to cope up with insecticidal stress by refolding damaged proteins. The PPI network analysis revealed the key genes common to both the comparison groups and their involvement in various pathways. The up-regulated ubiquitin genes RpS27A and RPL40 evidenced the activation of ubiquitin-PINK1-Parkin-dependent mitophagy pathway in response to ethion-induced cellular stress.