The Power of Two… Insecticidal Proteins

A mixture of insecticides containing the widely used Bt toxin and a novel plant protein, Mir1-CP, may be more lethal to crop pests than either ingredient used alone, scientists from the Pennsylvania State University discovered. The mixture also reduces the chance of the insects developing resistance and inhibits the insects’ growth rate. The insecticide cocktail was found to be effective against the corn earworm, tobacco budworm and the fall armyworm among other insect larvae.

The insecticidal proteins in the mixture work in synergism. Bt toxins bind to chemical receptors lining the insect gut, disrupting the receptors’ function and eventually killing the insects. Mir1-CP, on the other hand, is a cysteine protease. It has the ability to degrade specific protein and peptide components of the protective membrane covering the insect midgut. The membrane acts as a barrier that protects the insect larvae from toxins in the diet.

Maize plants accumulating increased levels of Mir1-CP have been developed. These varieties can be crossed with Bt maize lines to develop new pest resistant varieties.

Read more at http://live.psu.edu/story/29318