When corn calls worms to the rescue
The National Centres of Competence in Research (NCCRs) are networked worldwide. The innovative approaches in pest control in the NCCR “Plant Survival – Plant Survival in Natural and Agricultural Ecosystems" would have been inconceivable without the cooperation of researchers in Switzerland, Germany and the U.S.A.
Plants are not without their own defence mechanisms. Some deploy extremely ingenious strategies to defend themselves against bugs, caterpillars and other animals that would otherwise eradicate them. These natural defence mechanisms are of particular interest to the researchers in the NCCR "Plant Survival ". A group of researchers led by Ted Turlings at the University of Neuchâtel discovered that corn plants secrete a scent when attacked by the larvae of the western maize root borer (Diabrotica virgifera virgifera). The scent attracts tiny thread worms that kill the pest larvae.
When the researchers analyzed how widespread this ability is in modern corn varieties, they took advantage of their pan-European contacts at the CABI Bioscience Switzerland Research Institute in Delsberg which is involved in the NCCR “Plant Survival”. In experiments on fields in Hungary which were under heavy attack from the maize root borer larvae, the researchers found out that most corn strains cultivated in the U.S.A. lost the ability to secrete a scent signal when attacked by the maize root borer.
The 28 year old Ivan Hiltpold studied this phenomenon in greater detail in his doctoral dissertation at the University of Neuchâtel." In the U.S.A. and Canada corn’s main enemy is the maize root borer. It is estimated that damage and costs for pesticides amounts to a billion dollars every year," explains Ivan Hiltpold. The maize root borer arrived in Europe in the 1990s and initially spread primarily across Eastern Europe. "It is slowly working its way to Western Europe. For several years now it has been putting in appearances in Tessin," continues Ivan Hiltpold.
Ivan Hiltpold assumed that the absence of defence mechanisms would have a genetic explanation. As an ecologist, he therefore sought the cooperation of geneticists at the Max Planck Institute for Chemical Ecology in Jena, Germany. A young researcher, Ivan Hiltpold believes that the reputation of the NCCR “Plant Survival” was a decisive factor in allowing him to work with partners abroad. "If you are part of a network like this, other researchers are more willing to trust you."
Once again, the researchers benefited from their network. Ivan Hiltpold tested the genetically engineered strains in the Neuchâtel laboratory. He received renewed support from his colleagues at CABI (a non-profit agricultural and environmental NGO) who bred the maize root borer larvae. And his close contacts with agricultural researchers from the University of Missouri in the USA. finally enabled a test of new corn strains in the field. Both laboratory and field tests showed that the new strains were armed against the attacks by the maize root borers: the released scent immediately attracted the thread worms that rescued the corn plants from their unfortunate situation. "Without the broad-based network, it would have been impossible to complete my project," remarks Ivan Hiltpold. Although his doctoral dissertation is finished, he remains in contact with the extensive network.
The natural ability to ward off pests studied by the researchers in this network, is not limited to corn; it served as a model for the researchers. "Chemical signals transmitted by scent are certain to occur in many other plants," assumes Ted Turlings. As a result, the research networks established by the NCCR “Plant Survival” researchers have opened up long-term possibilities.