Resistance Mechanisms Of Cyhalothrin In Spodoptera Exigua (H(?)bner)

Beet armyworm,Spodoptera exigua(H(?)bner)(Lepidoptera:Noctuidae)are major pests of numerous cultivated crops.Using of chemical insecticides controlling S.exigua frequently had led to the development of insecticide resistance.Pyrethroid insecticides is the main target site of voltage-gated sodium channel,metaflumizone and indoxacarb are sodium channel blockers,the mode of action of selectively binding to the slow inactivation of sodium channels.Due to use of pesticides extensivly,such resistance is increasingly prominent.This paper reports the resistance of Spodoptera exigua to three insecticides,cyhalothrin,indoxacarb and metaflumizone,we cloned the full length of the sodium channels sequence,by amino acid sequence differences than confrontational and susceptible strains sodium channel gene,analyze the relationship between voltage-gated sodium ion channel mutations and resistance.Also antagonistic strain and susceptible strain between the sodium channel gene splicing has been studied to reveal the Spodoptera exigua cyhalothrin,metaflumizone and resistance mechanisms indoxacarb.It also reported that the TipE accessory protein gene.The main results are as follows:1.Monitoring resistance of Spodoptera exiguaThis study monitoring resistance of Spodoptera exigua with an approach of leaf-dip bioassay method in,which using the cyhalothrin,indoxacarb and metaflumizone three agents compared with the susceptible strain,compared with the susceptible strain the area beet armyworm field population cyhalothrin fold resistance up to very high levels(309.5-fold)for indoxacarb and metaflumizone resistance up to high levels,respectively,for the three types of pesticides resistance factor were 309.5,85.3 times and 42.5 times.These three agents were used for the interior resistance screening populations,after eight generations screening cyhalothrin resistance level further rises up to 398 times,metaflumizone selection of resistant up to 60-fold increased slightly,while the indoxacarb screening did not make resistance to rise further(85.5 times).2.Cloning voltage-gated sodium channel and identification of gene mutationsThis is the first report of the full-length sequence of Spodoptera exigua voltage-gated sodium channel gene,the gene encodes a 1793 amino acid protein,with the typical structure of voltage-gated sodium ion channels.Comparative analysis of sequence and deduced amino acid sequence between ORF resistant strain and susceptible strain sodium channel gene base and found that there are a lot of nucleotide base sequence polymorphisms sodium channels,but the translation the amino acid sequence between the resistant strain and susceptible strain did not find a stable mutation,there is only a partial amino acid polymorphism,indicating that the resistant strain to cyhalothrin resistance level is extremely high,and it is no matter the voltage-gated sodium channel mutation.3.Studying on voltage-gated sodium channel gene alternative splicingOn the basis of the voltage-gated sodium channel gene obtained from Spodoptera exigua we are studing alternatively splicing.Gene expression from the Spodoptera exigua obtained nine voltage-gated sodium channel spliceosome,these alternative splicing occurs mainly at the 5,end of the gene.We also analysis protein domain,there is a missing about SeNav-Seql and SeNav-Seq6 of Domain ? and Domain? S1-S5,while SeNav-Seq3 of Domain ? S1-S5,SeNav-Seq9 has a complete domain and the expression levels of these four spliceosome were found in the quantitative analysis of the Spodoptera exigua resistant and susceptible strains and two drug-treated susceptible strains.The expression was higher than the susceptible strain,SeNav-Seql and SeNav-Seq6 expression amount is higher than the susceptible strain resistant strains,susceptible strain SeNav-Seq3and SeNav-Seq9 expression higher than in the resistant strain,insecticide-treated is between sensitivity and resistance.We speculate that different splicing and pesticides affect the binding activity to raise or lower,which may result in this populations to produce high levels of resistance to cyhalothrin.4.The research of voltage-gated sodium ion channel accessory proteinsThe normal function of the insect voltage-gated sodium ion channels requires another subunit(accessory proteins)synergy.This paper describes the clone TipE and TipE-homologous genes has been TipE and Teh1-3 full-length sequence,it shortest length 947bp,the longest 1606bp.The using of Spodoptera exigua experimentally their relative amounts of mRNA in different tissues of different genes were found to be expressed epidemis,head,midgut,malpighian tubules,fat body tissues,and its expression differences in volume,we needs further study whether there is a correlation between TipE protein and resistance.