饲喂CYP6CM1和Coe1 RNAi双价转基因烟草对Q型烟粉虱抗药性的影响

Effect of transgenic tobacco expressing CYP6CM1-Coe1 RNAi cassette on insecticide-resistance of Q-type Bemisia tabaci

细胞色素P450酶系和羧酸酯酶在昆虫代谢抗药性中起重要作用,通过RNAi沉默昆虫这两种酶的基因,研究其对Q型烟粉虱抗药性的影响.根据Q型烟粉虱的一个P450基因（CYP6CM1）和一个羧酸酯酶基因（Coe1）的特异区域构建双价RNAi载体,农杆菌介导转化烟草,PCR检测获得5个单独的To代转基因株系.饲喂烟粉虱T1代转基因烟草,荧光定量PCR检测发现取食转基因烟草的烟粉虱体内CYP6CM1基因和Coe1基因表达量仅为取食非转基因烟草烟粉虱的18％ ～24％和17％～33％;通过琼脂保湿浸叶法和单株活体法研究取食T1代转基因烟草的烟粉虱对杀虫剂的效应,结果发现在接触1 g/L阿维·吡虫啉72 h后,2种方法中取食转基因烟草的烟粉虱死亡率分别比取食非转基因烟草的烟粉虱死亡率升高14.77％～16.46％和16.01％～18.51％;同样,接触稀释1 000倍的40％辛硫磷（体积比）72 h后,2种方法中烟粉虱死亡率升高22.94％ ～ 23.58％和17.4％～18.76％.以上结果表明,转CYP6CM1-Coe1 RNAi基因烟草可以显著降低烟粉虱CYP6CM1基因和Coe1基因的表达,降低烟粉虱对烟碱类杀虫剂阿维·吡虫啉和有机磷类杀虫剂辛硫磷的抗药性,显著提高杀虫剂的防治效果.

Cytochrome P450 monooxygenases and carboxylesterase are responsible for metabolically-based resistance to insecticide. The effect of silencing their genes by RNAi on insecticide-resistance of Bemisia tobaci was studied. A RNAi cassette targeting a P450 gene （ CYP6CM1 ） and a carboxylesterase gene （ Coel ） of Bemisia tobaci was inte- grated into tobacco genome through Agrobacterium transfor- mation, and five independent To lines were confirmed by PCR. Quantitative qRT-PCR results showed that the expressions of CYP6CM1 and Coel in Bemisia tabaci fed with transgenic tobacco T1 lines only accounted for 18% -24% and 17%-33% of those fed with non-transgenic tobacco, respectively. When exposed to 1 g/L abamectin-imidacloprid for 72 h, the mortalities of B. tabaci fed with transgenic tobacco were increased by 14.77% -16.46% and 16.01% -18.51% , respectively. When exposed to 1 000 times-diluted phoxim （40%） for 72 h, the mortalities of B. tabaci fed with transgenic tobacco were increased by 22.94% -23.58% and 17.4% -18.76%, respectively. It was indicated that transgenic tobacco expressing CYP6CM1-Coel RNAi cassette effectively interfered the expressions of CYP6CM1 gene and Coel gene in Bemisia tabaci and decreased the insecticide resistance to abamectin-imidacloprid and phoxim, resulting in an improved efficacy of insecticide.