Study On Detoxification Metabolism Mechanism And Target Binding Ability Of Diaphorina Citri To Cycloxaprid

Diaphorina citri is the main natural vector of Citrus Huanglongbing,so control of D.citri is a necessary measure to suppress the spread of Citrus Huanglongbing.At present,chemical control is still the main method for the control of D.citri,but it has been reported that some insecticides such as imidacloprid have developed resistance to D.citri.As a neonicotinoid pesticide with low toxicity to the environment and wide insecticidal spectrum,cycloxaprid has good control effect and important application value in the field control of D.citri.According to existing reports,several detoxification metabolic enzymes are involved in the detoxification metabolism of D.citri to insecticides.Based on this,the preliminary study on the detoxification metabolism mechanism of D.citri to cycloxaprid was carried out,so as to provide theoretical basis for scientific prevention and control of D.citri,resistance management and promoting the wide application of cycloxaprid in agricultural production.1.The toxicity of cycloxaprid and imidacloprid to D.citri strains was determined by insecticide film method.The LC₅₀ of cycloxaprid and imidacloprid to susceptible and field strains were 0.13 mg/L and 1.3mg/L,respectively.The LC₅₀ of imidacloprid to Susceptible and field strains were 0.21 mg/L and 6.20 mg/L,respectively.The results showed that compared with imidacloprid,the toxicity of cycloxaprid to D.citri was higher,and it was possible to achieve better control effect in the field.2.The enzyme activities of P450,GSTs,EST and the content of ABC transporter in the two strains of D.citri were determined by ELISA after cycloxaprid(LC₁₀)stress（12,24,36,48 h）.The results showed that the enzyme activities and the content of ABC transporter in Susceptible strains were significantly higher than that in Field strains.The activity of the enzyme and the content of ABC transporter increased significantly with time,which was significantly different from that of the control group.The results showed that P450,GST,EST and ABC transporter were involved in the detoxification of D.citri to cycloxaprid.3.CYP4C1,Dc GSTd1,EST4 and Dcit ABCH6 are overexpressed in D.Citri by detecting the m RNA expression levels of 74 detoxification enzymes and transporter genes related to detoxification metabolism.After CYP4C1,Dc GSTd1,EST4 and Dcit ABCH6 were silenced by RNAi technology,the sensitivity of D.Citri to cycloxaprid was significantly increased by 1.5 to 2.5 times.The overexpression of CYP4C1,Dc GSTd1,EST4 and Dcit ABCH6 in D.Citri is related to the detoxification metabolism of cycloxaprid.4.Biacore was used to determine the binding ability between nicotine acetylcholine receptor targets and cycloxaprid and imidacloprid in two strains of D.Citri.The results showed that the binding force of imidacloprid to Susceptible strains was 3.604 times that of Field strains,and the binding force of cycloxaprid to Susceptible strains was 1.405 times that of Susceptible strains.These results indicated that the decreased sensitivity of D.Citri to insecticides might be related to the insensitivity of target.