However, with lasting cultivation of Bt crops, increasing insect resistance to transgenic crops and outbreaks of nontarget pests were reported (Bravo and Soberon 2008 Gahan et al.

Engineering crop plants to express genes coding for insecticidal crystalline proteins from Bacillus thuringiensis ( Bt), so-called Cry toxins, has achieved great success both economically and ecologically (Qaim and Zilberman 2003 Wu et al. In the past three decades, transgenic technology has been developed to generate insect-proof plants to reduce yield loss and pesticide utilization (Bale et al. Host plants of this generalist lepidopteran include not only cotton but also other crop species. Cotton bollworm ( Helicoverpa armigera) is one of the most destructive agricultural pests, causing severe yield loss in crop production. These results demonstrated that transgenic cotton plants expressing dsCYP6AE14 acquired enhanced resistance to cotton bollworms, and that RNAi technology can be used for engineering insect-proof cotton cultivar.Ĭrop plants are widely cultivated and suffer from attacks by insect herbivores (Gassmann et al. Quantitative reverse-transcription polymerase chain reaction (RT-PCR) showed that the CYP6AE14 expression level was reduced in the larvae as early as 4 h after feeding on the transgenic plants accordingly, the CYP6AE14 protein level dropped. Bollworm larvae reared on T2 plants of the ds6- 3 line exhibited drastically retarded growth, and the transgenic plants were less damaged by bollworms than the control. Here we report generation and analysis of dsRNA-expressing cotton ( Gossypium hirsutum) plants. Bollworms fed on transgenic dsCYP6AE14 plants showed suppressed CYP6AE14 expression and reduced growth on gossypol-containing diet (Mao et al., in Nat Biotechnol 25: 1307–1313, 2007). Previously, we generated Arabidopsis and tobacco plants expressing double-stranded RNA (dsRNA) targeting a cotton bollworm ( Helicoverpa armigera) P450 gene, CYP6AE14. RNA interference (RNAi) plays an important role in regulating gene expression in eukaryotes.

Stranded by J.C. Valentine