Proteomic evaluation of pathways associated with phosphine-induced mitochondrial dysfunction and resistance mechanisms in Tribolium castaneum against phosphine fumigation: Whole and partial proteome identification

Phosphine (PH₃) fumigation is widely used to control insect pests in stored products globally. However, intensive PH₃ use has led to the emergence of significant resistance in target insects. To address this issue, this study investigated PH₃ resistance mechanisms by conducting both qualitative and quantitative proteomic analyses on the whole proteome of a PH₃-resistant Tribolium castaneum strain (AUS-07) using LC-MS/MS. Besides, proteins from both strains were separated in 1D-PAGE, and qualitatively analyzed using LC-MS/MS after in-gel digestion. Differentially expressed proteins (DEPs) with cut-off values (4-fold expression difference and p < 0.05) were selected, and 107 proteins were identified in the AUS-07 strain. Among them, several proteins involved in oxidative phosphorylation were notably upregulated in response to PH₃ exposure. Upregulation of Complex I and III in the electron transport chain of the AUS-07 strain may lead to the excessive generation of reactive oxygen species (ROS) in the form of superoxide, which can damage Fe-S cluster-containing proteins such as cytochrome P450s (CYP450s). Upregulation of detoxifying enzymes, such as CYP450s and glutathione S-transferases (GSTs), was observed, likely to repair superoxide-induced damage on CYP450s as well as quenching superoxide. Upregulation of aldose reductases involved in polyol pathways and downregulation of the trehalose transporter were observed, suggesting that PH₃-resistance may be linked to diapause-like physiological adaptations, including quiescence. Further studies are essential to quantify polyol levels in the AUS-07 strain and to conduct other molecular analyses to validate the roles of identified DEPs in PH₃ resistance. Altogether, our findings suggest a new control strategy to stored product insect pests by other type of fumigant such as ethyl formate with different molecular structure.