Effect of glucosinolates on three detoxifying enzyme activity of the pea aphid Acyrthosiphon pisum

The aim of this study was to investigate the effects of plant secondary glucosinolates on three detoxification enzymes in aphid pea. In this study, pea aphid was fed pure artificial diet; the treatment groups include the control group ( 0 μmol·g⁻¹) and three groups fed with diet supplemented with glucosinolates at different concentrations (0.94, 1.87, 2.86 μmol·g⁻¹). Changes in detoxifying enzyme activity and soluble protein content in artificial diets containing different glucosinolate concentrations were measured. The results showed that the enzyme activities of carboxylesterase (CarE), glutathione S-transferase (GSTs), and cytochrome P450s (P450s) increased gradually when two morphs of pea aphid were fed artificial diets supplemented with different concentrations of glucosinolates, and the soluble protein content increased in varying degrees. With increases in the feeding time and glucosinolate concentration, the activities of the three detoxification enzymes increased. Compared to 0.94 μmol·g⁻¹ group, the 1.87 and 2.86 μmol·g⁻¹ groups were significantly different (P < 0.05). In this study, the enzyme activities of CarE, GSTs, and P450s gradually increased. Compared to CarE and GSTs, the enzyme activities of P450s were significantly higher (P < 0.05), and at 2.86 μmol·g⁻¹, the enzyme activity of P450s was 4.60 and 1.90 times higher than that of the control, respectively. The results indicated that the detoxification metabolism of different pea aphids had different response mechanisms to glucosinolates.