Establishment Of Dinotefuran Resistant Strain And Detoxifying Enzymes In Apolygus Lucorum Meyer-dür

Apolygus lucorumMeyer-dür belonging to the order Hemiptera,Miridae,isan omnivorous insects withvarious host,and also widely distributed in Asia,Europe,Africa and the United States.Especially in China,A.lucorum has become one of the most serious pests in cotton and other cash crops for recent years,with the characteristics oflong life history and serious overlapped generation.It is difficult to control these species due to high mobility,broad host range and cryptic damage.At present,the main control of A.lucorum Meyer-dür is still relying on chemical control.However,long-term use of insecticide may cause resistance and increase the control difficulty.Based on previous research,the green beans was chose as food of A.lucorumMeyer-dür.We adopted the same food source for the successive rearingof A.lucorum.The toxicity of dinotefuran against A.lucorum and its resistant strain were determined by the topical method.The activities of the detoxifying enzymes including esterase and glutathione S-transferase were compared to determine which enzyme was involved in the metabolism of dinotefuran resistance in A lucorum.After twelve generations of indoor selection with dinotefuran,the resistance of dinotefuran reached nearly five times,showing a low level of resistance,suggesting that the potential for the high resistance development is small.The resistance of dwarf insects to dinotefucius was increasing by wave,but the increase of resistance fold was very slow.By measuring the changes of carboxylesterase and glutathione S-transferase activity,it is speculated that carboxylesterase is likely to be involved in the metabolism of dinotefuran.Two cytochrome P450 genes named CYP395G1 and CYP4EY1 in Apolygus lucorum Meyer-dürwere cloned With the the sequences comparison of Apolygus lucorumCYP395G1,CYP4EY1and other insect P450,CYP395G1 has the sequence identity of 30%with other insect CYP family,whileCYP4EY1 has the sequence identity of 60%with other insect CYP4 family.The relative expression of CYP395G1 and CY4EY1were various at different developmental stages of Apolygus lucorum Meyer-diir.Though short-term induction of the dinotefuran,the expression of CYP395G1 in adult 6h,12h,24h,36h and 48h was 1.26,1.91,0.92,0.50 and 0.37 times higher than that in controls.In adults,the expression levels of CYP4EY1 in 6h,12h,24h,36h and 48h were 1.02,0.64,0.53,0.40 and 0.36 times higher than those in controls.Through long-term stress of the dinotefuran,the transcriptional expression of CYP395G1 was significantly increased,while CYP4EY1 was not obviously increased,speculatingCYP395G1 gene may participate in the detoxification process of dinotefuran.In this research,initially,the cDNA sequences of two cytochrome P450 genes were identified.The development stage expression patterns of the P450 genes were determined.Comparing analysis of transcriptional expression of the two P450 genes in resistant and susceptible strains ofA.lucorum was performed.It is therefore important to elucidate mechanism of dinotefuran resistance.