Transgenic plants expressing Bt gene have been widely used for pest control for the past several years. However, due to certain limitations associated with using this technology scientists have been looking for alternatives, and they found one in RNAi. The researchers at the Chinese Academy of Sciences, Shanghai, and at Monsanto and Devgen, a Belgian company have shown for the first time that RNAi could be used as an efficient means of pest control. In two independent studies, when scientists fed the insect larvae with the plant material expressing dsRNA for the insect genes, it was found that it triggered the RNAi pathway in insect larvae and blocked the expression those genes.
In the first study, cotton bollworm (Helicoverpa armigera) was the target. dsRNA for a cotton bollworm cytochrome P450 gene, CYP6AE14, was made to express in the plants. This plant material was then fed to the insect larvae, and it was found that the levels of the cytochrome P450 transcript in the larval midgut decreased and larval growth retarded. This cytochrome P450 gene permits Helicoverpa armigera to tolerate inhibitory concentrations of the cotton metabolite, gossypol, and survive. In the absence of this gene, the insect showed decline in its growth. The abstract is here.
In another study, scientists made corn plants that silenced a gene essential for energy production in corn rootworms. Read the abstract here.
Many research workers are optimistic about this technology. Read the full story here.
via: Technology Review