Study On Sublethal Dose Of Avermectin To The Different Thermal Strains Of Experimental Group Of Neoseiulus Barkeri(acari: Phytoseiidae)

Neoseiulus barkeri(Hughes),belongs to Phytoseiidae,Parasitiformes,Acari,Arachnida,which can prey on some small and little pests,such as spider mites,thrips.N.barkeri is considered as one of the most important biological control agents worldwide.The objects of this study was to investigate the sublethal dose of avermectin to the conventional strain(CS)and high temperature adapted strain(HTAS)of N.barkeri.On the basis of the bioassay to the CS N.barkeri and HTAS N.barkeri,a series of studies we carried out.Sublethal doses of avermectin to the effect of functional response and activity of detoxifying enzymes between CS N.barkeri and HTAS N.barkeri,including time course effects and dose effects.Meanwhile,the expression profiles of 10 genes about detoxification metabolism after treatment with avermectin in dose and different times were investigated in the present study.The main research contents and results are as follows:1.The toxicity of avermectin to CS N.barkeri,HTAS N.barkeri and the prey Tetranychus urticae.Bioassay tests were carried out against the female adults of CS N.barkeri and HTAS N.barkeri and their prey of Tetranychus urticae by the method of modified RCV.The results showed that the LC10,LC20,LC30 and LC50 of avermectin to female adults of CS N.barkeri were recorded as 1066.42mg/L,1739.56mg/L,2475.57mg/L and 4435.98mg/L,respectively.The LC10,LC20,LC30 and LC50 of avermectin to female adults of HTAS N.barkeri were recorded as 565.10mg/L,910.08mg/L,1283.23mg/L,2264.59mg/L,respectively.The LC50 of avermectin to female adults of T.urticae was recorded as 0.355 mg/L.2.Sublethal effect of avermectin on the predatory function between CS N.barkeri and HTAS N.barkeri.In this study,we investgated the functional response of female adults of CS N.barkeri and HTAS N.barkeri on the eggs of T.urticae when the predators treated with avermectin in LC10,LC20,LC30,respectively.The results showed that different doses of avermectin could cause the predatory capacities decreased both in CS N.barkeri and HTAS N.barkeri,and bigger of the sublethal dose of avermectin,bigger the affect.The predatory capacities of CS N.barkeri were higher than it was of HTAS N.barkeri in the same sublethal dose of avermectin.And the functional response models were all still con-formed to the Holling's type II curve in spite of pretreated with sublethal doses of avermectin,just only with the parameters of models changed,such as reduced the attack rate (6,extended the handling time ?,decreased predation capacity (6/?,as well as decreased the number of daily maximum predation 1/?.After pretreated with sublethal doses of avermectin,the consumption of N.barkeri against prey was thus reduced.3.Sublethal effect of avermectin on the activity of detoxifying enzymes between CS N.barkeri and HTAS N.barkeriIn this study,we studied the dose effect and time effect on GSTs,MFOs and Car Es both in CS N.barkeri and HTAS N.barkeri pretreated with sublethal doses of avermectin.The results showed that sublethal doses of avermectin have some inhibiting effects on the activity of the GSTs both in CS N.barkeri and HTAS N.barkeri.There was a certain dose effect and time effect,that was,the bigger of the dose or the longer of the time had been treated,the activity of the GSTs reduced more.And avermectin had a greater inhibiting effect on the HTAS N.barkeri than CS N.barkeri.Sublethal doses of avermectin had some inducible effect to the activity of the MFOs and Car Es both in CS N.barkeri and HTAS N.barkeri,and there was also worked in a certain dose effect and time effect manner.When the concentration of avermectin was relatively low,the inducible effect to the activity of the MFOs and Car Es is stonger both in CS N.barkeri and HTAS N.barkeri.The activity of the MFOs and Car Es was increased,to resist the risky outside surroundings.And then with the concentration increased,the inducible effect was weakened.The longer of the treatment time of avermectin in LC30,the stonger of the inducible effect in HTAS N.barkeri,but the inducible effect in CS N.barkeri would be weakened.4.Detoxification metabolism genes expression profiles from CS N.barkeri and HTAS N.barkeri treatment with avermectin.In this study,we found the three kinds of genes about detoxification metabolism,which was annotated in transcriptome data among N.barkeri.And then we carried out the systematic evolutionary analysis of them.Using Beta-actin as a reference gene,we verified the detoxification metabolism genes used the RT-q PCR technology.We studied and analyzed the dose effects and time course effects of avermectin on the expression profiles of ten genes about detoxification metabolism,four genes about GSTs,four genes about MFOs,two genes about Car Es,in CS N.barkeri and HTAS N.barkeri.Then we cleared the change tendency of the m RNA relative expression about the ten detoxification metabolism genes after N.barkeri treatment with avermectin.So we could provide some references to cultivate the resistant strains of N.barkeri.The results showed that,about CS N.barkeri,the relative expression of GST1,GST2,CYP3 and CYP4 were down-regulated after treatment with avermectin at different concentrations and different times at LC30,but the range of down-regulated was different.The relative expression of GST3 was down-regulated after treatment with avermectin at lower concentrations,but the relative expression of GST3 was up-regulated when the concentration was higher.The relative expression of GST3 was up-regulated after treatment with avermectin at different times,and the range of up-regulated was changable with the time extension.The relative expression of GST4 was up-regulated when treated with avermectin at different concentrations,and the range of up-regulated was different.The relative expression of GST4 was up-regulated treatment with avermectin after 6 hours and 24 hours,but down-regulated after 12 hours.The relative expression of CYP1 increased with the dose of avermectin increased.The relative expression of CYP1 was down-regulated treatment with avermectin after 6 hours and 12 hours,but up-regulated after 24 hours.The relative expression of CYP2 was down-regulated after treatment with avermectin at LC10 and LC30,but up-regulated at LC50.The relative expression of CYP2 was down-regulated after treatment with avermectin at different times.The relative expression of Car E1 and Car E2 were up-regulated after treatment with avermectin at smaller concentrations,the range of up-regulated was decreased or even down-regulated when the concentration was larger.The relative expression of Car E1 and Car E2 were up-regulated treatment with avermectin after 6 hours,and down-regulated with the time extension,and increased a little after 24 hours.The results showed that GST1,GST2,CYP3 and CYP4 may not participate in the detoxification metabolism of avermectin in CS N.barkeri.And GST3,GST4,CYP1,CYP2,Car E1 and Car E2 may participate in the detoxification metabolism of avermectin in CS N.barkeri,so they may also be involved in the formation of resistance to avermectin at CS N.barkeri.About HTAS N.barkeri,the relative expression of GST1 and GST2 were up-regulated after treatment with avermectin at smaller concentrations,and the range was different,but down-regulated after treatment with avermectin at LC50.The relative expression of GST1 and GST2 were up-regulated after treatment with avermectin at different times,and the range was different,reached the top at 12 hours.The relative expression of GST3 was up-regulated after treatment with avermectin at smaller concentrations,and the range was different,but down-regulated after treatment with avermectin at LC50.The relative expression of GST3 was down-regulated treatment with avermectin after 6 hours and 12 hours,but up-regulated after 24 hours.The relative expression of GST4 was up-regulated after treatment with avermectin at different concentrations,the range of up-regulated was increased when the concentration was larger.The relative expression of GST4 was up-regulated after treatment with avermectin at different times,and the range was different,reached the top at 12 hours.The relative expression of CYP1 was up-regulated after treatment with avermectin at different concentrations,and the range of up-regulated was decreased with the dose increased.The relative expression of CYP1 was up-regulated after treatment with avermectin at different times,but there was no significant difference.The relative expression of CYP2 was up-regulated after treatment with avermectin at LC10,and was down-regulated with increased of the dose.The relative expression of CYP2 reached the top after treatment with avermectin at 6 hours,7.27 times than control.The range of up-regulated was decreased or even down-regulated when the time longer.The relative expression of CYP3,CYP4,Car E1 and Car E2 were up-regulated after treatment with avermectin at smaller concentrations,the range of up-regulated was decreased or even down-regulated when the concentration was larger.The relative expression of CYP3,CYP4,Car E1 and Car E2 were up-regulated after treatment with avermectin at different times,and the range was different,reached the top at 6 hours.The results showed that GST1,GST2,GST3,GST4,CYP1,CYP2,CYP3,CYP4,Car E1 and Car E2 may all participate in the detoxification metabolism of avermectin in HTAS N.barkeri,so they may also be involved in the formation of resistance to avermectin at HTAS N.barkeri.Through the several aspects research above,which can not only provide some references for the N.barkeri release in the field,but also can judge which detoxifying enzymes or which genes about detoxifying enzymes may participate in the CS N.barkeri and HTAS N.barkeri against for avermectin.The results also can offer some academic basis to cultivate the strains which can resist avermectin at N.barkeri.