Resistance Rick Assessment Of Bemisia Tabaci To Afidopyrope And Resistance Mechanism Of Bemisia Tabaci

The sooty fly（Bemisia tabaci）belongs to the Hemiptera family of whiteflies,and is an important agricultural pest on crops and flowers.The high reproductive capacity of the whitefly,serious overlap of generations and over-reliance on chemicals in the control process have led to the development of resistance of the whitefly to a variety of chemicals.Afidopyrope,the introduction and application of new chemical insecticides remains a key strategy to prevent outbreaks of agricultural pests as well as the development of resistance.As a new insecticide officially registered in China in 2019,this study was conducted to monitor the resistance of sooty fly populations in domestic areas using Afidopyrope,and to conduct sublethal studies for Afidopyrope.The transcriptome was used to clone and identify the TRPV gene,the molecular target of Afidopyrope,and analyze its expression profile to provide a basis for the field application of Afidopyrope against the whitefly,and resistance management.The main findings are as follows:1.It is clear that Afidopyrope has high insecticidal activity against the whitefly and can be used for the field control of whitefly.Eighteen field populations of sooty fly were monitored for resistance using the agar moistened leaf dip method.The results showed that compared with the indoor sensitive whitefly population,the greenhouse whitefly population（HD）in Haidian,Beijing,showed about 40-fold resistance to bifenthrin and 14.3-fold cross-resistance to fludioxonil.2.to further clarify the sublethal concentration2.It was further clarified that Afidopyrope at sublethal concentrations would inhibit the growth and development and population reproduction of the whitefly,and had significant pest control effects.The results showed that the developmental time and survival rate of 2nd instar to adult whiteflies were significantly reduced under LC₁₀and LC₂₅ treatments compared with the control.The mean egg production,egg laying time and egg hatching rate of female adults were significantly reduced under LC₂₅ treatment,but no significant difference was found under LC₁₀ treatment.3.Two target genes,Nan and Iav,were cloned and identified for the first time,and their expression patterns were analyzed in whiteflies,which provided a theoretical basis for subsequent gene function verification.Screening the sequence information of two isoforms of TRPV channel genes based on the sooty fly genome and transcriptome data.The ORF lengths of BtNan and BtIav genes were 3612bp and 2956bp,and the number of amino acids encoded were 1204 and1036,respectively.Phylogenetic and Motif analyses showed that there was a high degree of consistency between the TRPV and other species TRPV protein sequences of B.fumigatus,and the B.fumigatus TRPV channel genes clustered with other species TRPV channel genes and were highly conserved.Structural analysis of the BtNan and BtIav proteins showed typical common features between BtNan and BtIav,with each subunit having five anchor protein structural domains,and six transmembrane regions（TM1～TM6）.Analysis of the spatiotemporal expression patterns of both BtNan and BtIav genes showed that BtNan and BtIav were expressed at all developmental stages of the sooty midge,but the expression was significantly higher in the head than in the thorax and abdomen.In addition,the expression of BtNan gene was significantly up-regulated after 12h and 48h of bipropionate treatment.