Crop Biotech Update

Silencing of Carboxylesterase Gene to Weaken Aphids' Insecticide Tolerance

November 20, 2013

China Agricultural University scientist Lanjie Xu and colleagues used plant-mediated RNAi technology targeting aphids (Sitobion avenae) to enable gene silencing in the aphid and to lessen the handling of the insects during experiments. They cloned carboxylesterase (CbE E4) gene in aphid which increased synthesis of a protein known to be critical to the resistance this species has developed to a wide range of pesticides.

They constructed plant RNAi vector and transgenic wheat lines (dsCbE1-5 and dsCbE2-2) expressing CbE E4 dsRNA were developed. The aphids were fed on transgenic wheat that produce the CbE E4 dsRNA. CbE E4 gene expression in the aphids was decreased by 30–60%. The number of aphids raised on the transgenic wheat was lower than the number raised on non-transgenic plants. A solution of CbE E4 enzyme from aphids fed on transgenic wheat plants hydrolyzed only up to 20–30% Phoxim solution within 40 minutes whereas a solution of the enzyme from CbE E4 fed on control plants hydrolyzed 60% of Phoxim solution within 40 minutes. CbE E4 gene silencing was achieved by the wheat-mediated RNAi approach.

The authors concluded that this plant-mediated RNAi approach could be useful in pest management for diverse agro-ecosystems.

Read the abstract at Transgenic Research: