Resilience in Tribolium Castaneum Through Antioxidant Priming Under Phosphine-Induced Oxidative Stress.

This study investigates the effects of sublethal and high-dose phosphine exposure on biocatalytic activity and gene expression of key antioxidants (catalase, peroxidase, and superoxide dismutase) in T. castaneum populations: susceptible (LS), weakly resistant (WR), and strongly resistant (SR). Multigenerational bioassays demonstrated a marked increase in resistance, with WR and SR populations exhibiting resistance ratios exceeding 30-fold following repeated phosphine exposure. Biochemical analyses revealed a significant decline in catalase activity (1.28-2.25-fold) in WR and SR populations, whereas peroxidase activity increased substantially, particularly in SR populations exposed to sublethal (3.25-fold) and high-dose (3.45-fold) treatments. Gene expression analysis normalized to RPS18, showed downregulation of catalase transcripts in WR and SR populations, alongside pronounced upregulation of peroxidase and superoxide dismutase (SOD) genes with increasing resistance. Multiple regression analysis revealed a strong association (R2 > 0.85) between resistance levels, antioxidant enzyme activities, and corresponding gene expression profiles. This study explores phosphine exposure, antioxidant defences, and resistance in T. castaneum, underscoring the need for continuous monitoring and adaptive management for sustainable resistance.