Fumarate mitigates disruption induced by fenpropathrin in the silkworm Bombyx mori(Lepidoptera):A metabolomics study

The silkworm Bombyx mori L.is a model organism of the order Lepidoptera.Understanding the mechanism of pesticide resistance in silkworms is valuable for Lepidopteran pest control.In this study,comparative metabolomics was used to analyze the metabolites of 2 silkworm strains with different pesticide resistance levels at 6,12,and 24 h after feeding with fenpropathrin.Twenty-six of 27 metabolites showed significant differences after fenpropathrin treatment and were classified into 6 metabolic pathways:glycerophospholipid metabolism,sulfur metabolism,glycolysis,amino acid metabolism,the urea cycle,and the tricarboxylic acid(TCA)cycle.After analyzing the percentage changes in the metabolic pathways at the 3 time points,sulfur metabolism,glycolysis,and the TCA cycle showed significant responses to fenpropathrin.Confirmatory experiments were performed by feeding silkworms with key metabolites of the 3 pathways.The combination of iron(II)fumarate+folic acid(IF-FA)enhanced fenpropathrin resistance in silkworms 6.38 fold,indicating that the TCA cycle is the core pathway associated with resistance.Furthermore,the disruption of several energy-related metabolic pathways caused by fenpropathrin was shown to be recovered by IF-FA in vitro.Therefore,IF-FA may have a role in boosting silkworm pesticide resistance by modulating the equilibrium between the TCA cycle and its related metabolic pathways.