COMPARATIVE TRANSCRIPTOMIC ANALYSIS REVEALS DIVERGENT RESPONSES TO BROFLANILIDE EXPOSURE IN DIAPHANIA PULVERULENTALIS AND BOMBYX MORI, HIGHLIGHTING MECHANISMS OF TOLERANCE AND SUSCEPTIBILITY

Abstract

Insecticide treatment in sericulture endangers the delicate silkworm, Bombyx mori, while seeking to suppress pests like the mulberry leaf webber, Diaphania pulverulentalis. Understanding the molecular responses of both species is necessary to develop safer pest management strategies. In this work, RNA sequencing (RNA-Seq) was used to evaluate the transcriptome profiles of D. pulverulentalis and B. mori larvae exposed to a sublethal amount (0.01 ppm) of the more modern insecticide Broflanilide. High-quality transcriptome data were generated from scratch for D. pulverulentalis and linked to a reference genome for B. mori. Studies on differential gene expression (DEG) revealed conflicting responses in D. pulverulentalis showed a robust response with 3,194 DEGs, primarily increased (2,992 genes), including detoxification-related genes (e.g., serine protease like, gelsolin). On the other hand, B. mori displayed extensive transcriptional repression, with 797 downregulated DEGs out of 802. Significantly, B. mori exhibited substantial repression of important silk protein genes (fibroin heavy chain, light chain, P25) (log₂FC< -12). In B. mori, functional enrichment analysis revealed disruptions in glycan biosynthesis, glutathione metabolism, DNA repair, and metabolic pathways (carbohydrate, lipid). In contrast to considerable physiological disruption and vulnerability in B. mori, these divergent transcriptome patterns indicate a better tolerance and adaptive detoxifying capacity in D. pulverulentalis. In addition to identifying possible gene markers for risk assessment and the development of silkworm strains with increased resistance to insecticide residues, the results offer genetic insights into insecticide selectivity.