"Instead of using insecticides, the use of natural enemies of the corn rootworm could be much more environmentally friendly," says Jrg Degenhardt, who was recently appointed professor at the University of Halle. While working in the group of Jonathan Gershenzon at the Max Planck Institute for Chemical Ecology in Jena he had already contributed to a key discovery four years ago by Sergio Rasmann in the group of Ted Turlings at the University of Neuchtel. They found that maize roots attacked by rootworm attract nematodes by releasing (E)-beta-caryophyllene (EβC). One striking finding was that, after decades of breeding, most North American maize varieties no longer emitted EβC and had lost the ability to attract protective nematodes.
Therefore the research group in Jena and Neuchtel teamed up again in an attempt to restore the EβC signal in a variety that normally does not emit the substance. Jrg Degenhardt, with the help of Monika Frey at the Technical University of Munich, transformed a non-emitting maize line with a gene that encodes an EβC generating enzyme, resulting in continuous emissions of EβC. Next, the Turlings group in Neuchtel sent Ivan Hiltpold to Missouri, where, under the guidance of Bruce Hibbard of the United States Department of Agriculture, the transformed plants were tested in the field.
"Our study showed that the re-established natural EβC signal greatly enhanced the effectiveness of nematodes in controlling Western corn rootworm", Hiltpold reports. In rows with EβC-producing maize plants root damage was greatly reduced; 60% fewer Diabrotica beetles emerged as compared to rows with non-transformed maize plants. This control efficiency approaches that of conventional synthetic insecticides used to fight Diabrotica. Subsequent laboratory studies c
|Contact: Joerg Degenhardt|
Max Planck Institute for Chemical Ecology