Recent Approaches in Developing Insect 'Proof' Plants

One of the major successes of plant biotechnology is the introduction of insect-resistance to important crops. Bt cotton and maize have been widely used in global agriculture and have led to significant reductions in pesticide usage. Not all pests, however, are efficiently targeted by the Bt toxins used at present. There is still a need to develop solutions for problems like Bt toxin resistance. A new review paper published by the journal Plant Physiology looks at the recent development to the basic Bt strategy and alternative methods to develop insect “proof” plants.

Plants expressing novel Bt toxins like Vip and Cry3Bb1 have been shown to be effective against lepidopteran larvae. Bt genes have also been expressed in the chloroplast genome, resulting to higher levels of toxin accumulation. Scientists are currently exploiting plant-defense proteins like lectins and alpha-amylase inhibitors to combat Bt resistant pests.

John Gatehouse, author of the review, enumerated novel approaches for engineering insect-resistant plants. These include:

• The use of new insecticidal proteins like cholesterol oxidase and avidin
• Increasing the expression of plant secondary metabolites like cyanogenic glycosides and volatile communication compounds
• RNA interference for targeting insect resistance genes

The article can be accessed for free at http://www.plantphysiol.org/cgi/content/full/146/3/881