Seed World

Smell Might Hold Key to Protecting Crops from Insects

Scientists in the United Kingdom might have uncovered a natural way of avoiding the use of pesticides by recreating a natural insect repellent.
Scientists from the School of Chemistry and Rothamsted Research have, for the first time, created tiny molecules that mirror a natural smell known to repel insects.
The scientists were able to make similar smelling insect repellent molecules, by providing the enzyme, ((S)-germacrene D synthase), which creates the smell, with alternative substrate molecules.
The effectiveness of the smell or perfume to function as an insect repellent was tested. The team found that the smells repelled insects but in one case a reversal of behavior — an attractant — was observed, which raises the prospect of being able to develop a trap-and-kill device.
“We know that many organisms use smell to interact with members of the same species and to locate hosts of food or to avoid attack from parasites,” shares Rudolf Allemann, who led the research and is head of the School of Chemistry. “However, the difficulty is that scientifically, smell molecules are often extremely volatile, chemically unstable and expensive to re-create. This means that, until now, progress has been extremely slow in recreating smells that are similar to the original.
“Through the power of novel biochemical techniques we have been able to make insect repellent smell molecules, which are structurally different but functionally similar to the original,” he adds.
Professor John Pickett, from Rothamsted Research says: “This is a breakthrough in rational design of smells and provides a novel way of producing a smell with different properties and potentially better ones than the original but at the same time preserving the original activity. By using alternative substrates for the enzymes involved in the ligand biosynthesis (biosynthesis of the smell), we can create the appropriate chemical space to reproduce, with a different molecular structure, the activity of the original smell.”
The team hopes that their research could provide a new way of designing and developing small smell molecules that would otherwise be too difficult to produce by usual scientific and commercial methods.