Cloning And Function Study Of The CYP6DV5 Gene Of Thiamethoxam Against Allergic Bemisia Tabaci

Bemisia tabaci is a worldwide agricultural pest in the family Hemiptera,which is harmful to crops in China by sucking plant sap and spreading virus.At present,the control of Bemisia tabaci mainly depends on chemical control.Thiamethoxam,as a second generation of new nicotine insecticide product,has unique structure and high-efficiency insecticidal activity,and is currently an important agent for the control of Bemisia tabaci.Recent research on resistance status of Q type B.tabaci in China demonstrated that resistance to thiamethoxam has developed in some strains.Previous study on the transcriptional and translational differences between the THQR and THQS strains has revealed that the gene CYP6DV5 was significantly over-expressed in the THQR strain.Thus our study is aimed at identifying that whether the gene is involved in the resistance of thiamethoxam in B.tabaci.Gene cloning and analysis presented that the CYP6DV5 c DNA contains a 1305-bp open reading frame encoding 435 amino acid residues.Quantitive real-time PCR results showed that CYP6DV5 is 2.96-fold over-expressed in the THQR than THQS strain B.tabaci adults.After knocking down the gene for 29.9% in THQR adults,the mortality was significantly higher than that control group.After feeding the B.tabaci of feeding fluid containing thiamethoxam for 3,6,12 and 18 h,comparing to the 3h group the expression level of CYP6DV5 can be up-regulated to 1.79-fold and 2.37-fold at the time of 12 and 18 h respectively.Bioassays for drosophilid overexpressed CYP6DV5 demonstrated that overexpression of CYP6DV5 can strengthen the resistance to thiamethoxam.Results revealed that CYP6DV5 is involved in thiamethoxam resistance in whiteflies.