Genetic Structure Analysis Of Different Geographical Populations Of Wheat Aphids In China,and The Regulation Function Of GPCRs To The Expression Of P450 Genes In House Flies

Sitobion avenae（F.）and Rhopalosiphum padi（L.）are usually coexistent and are important pests damage wheat production in China.In the present study,the microsatellite molecular marker and mtDNA-COI gene were used together to investigate the population genetic structure among different geographical populations of two wheat aphids species S.avenae and R.padi.1.The microsatellite molecular markers were used to analyze the population genetic structure among seven geographical populations of S.avenae.Results showed that:populations from Henan,Shandong,and Jiangsu had high levels of genic and genotypic diversity.By contrast,the genic diversity in Beijing and Hebei populations were much lower.Overall,genetic divergences among these seven S.avenae populations were high,though there was almost no differentiation between the Shandong and Henan populations.Result of mantel test showed that significant correlation between genetic differentiation and geographic distances among populations.Based on genetic structure analysis,these seven S.avenae populations studied can be divided into four distinct clusters;（i）Hubei,（ii）Shanxi,（iii）Beijing and Hebei,and（iv）Shandong,Henan,and Jiangsu.2.mtDNA-COI gene sequences were used to analyze the genetic structure of geographical populations of S.avenae.Results suggested that:total nucleotide diversity（Pi）was 0.3%;haplotype diversity（Hd）was 0.456;mtDNA-COI gene sequences revealed heavily biased on A and T nucleotides with 76.5%of A+ T.Thirteen haplotypes were detected in the present study.Among which,the haplotype H1_Sa had the widest distribution;haplotype H12_Sa was the specific haplotype only presented in Hubei population and the frequency of was high to 93.1%in Hubei population.The results of AMOVA showed that genetic differentiation of S.avenae in China has achieved to significant high level with Fs1=0.4604.Results of the genetic difference analysis suggested that Hubei population had significant divergence from the other populations;No significant genetic differentiation was detected among the four populations of Beijing,Hebei,Jiangsu and Shandong.3.Microsatellite molecular markers were used to analyze the population genetic structure among the eight geographic populations of R.padi in China.The results confirm that high degree of genetic diversity and population genetic differentiation presented among Chinese R.padi populations.High levels of genetic differentiation were detected beween R.padi populations in plateau areas（Yunnan and Tibet）and other populations.The genetic differentiation among the Beijing,Hebei,and Shandong populations was relatively low.Mantel tests revealed that the genetic differentiation among these populations had a significant positive correlation with geographic distance.Results of population genetic structure analysis showed eight R.padi populations can be divided into six distinct clusters:1)Beijing,Hebei and Shandong;2)Henan;3)Jiangsu;4)Hubei;5)Yunnan;6)Tibet.4.mtDNA-COI gene sequences were used to analyze the population structure of geographical populations of R.padi.Results suggested that:total nucleotide diversity（Pi）was 0.05%;haplotype diversity（Hd）was 0.224;mtDNA-COI gene sequences revealed heavily biased on A and T nucleotides with 75.1%of A+T.Ten haplotypes were detected in the present study.Among which the haplotype H1_Rp had the widest distribution and presented in every populations we detected,and Beijing,Hebei and Shandong were detected to have only one haplotype H1_Rp;haplotype H3_Rp was shared by Hubei and Henan;haplotype H6_Rp was shared by Hubei and Jiangsu.Results of AMOVA showed that the genetic differentiation of R.padi in China was at very low level with FST=0.0540.Taken together,the present researche successfully analyzed the genetic diversity,genetic differentiation and population structure,which provided valuable theoretical basis for researches of genetic differentiation of wheat aphids and migration route of resistant wheat aphids.The second part of the present dissertation was about the regulation function of GPCRs to the expression of P450 genes in house fly,M.domestica.Two important GPCR genes were found significantly over-expressed in the M.domestica insecticide resistant strain ALHF.ALHF₀2706.g1581,has been mapped on autosomal 2 in house flies.These two GPCR genes were then successfully transferred into Drosophila,and over-expressed in transgenic Drosophila.According to the bioassay result on permethrin,the resistant level of the Drosophila with GPCR transgenes significantly improved.Furthermore,the over-expression of GPCR gene ALHF₀2706.g1581 can promote the relative expression level of three P450 genes,cyp12d1,cyp6a1 and cyp6a8,up-regulate in transgenic Drosophila.Meanwhile,the over-expression of GPCR gene ALHF₀4422.g2918 can make two P450 genes cyp6g1 and cyp6a2 over-express.