Crops that kill pests by shutting off their genes

Plants are among many eukaryotes that can "turn off" one or more of their genes by using a process called RNA interference to block protein translation. 

Researchers are now weaponizing this by engineering crops to produce specific RNA fragments that, upon ingestion by insects, initiate RNA interference to shut down a target gene essential for life or reproduction, killing or sterilizing the insects. The potential of this method is reviewed in Trends in Biotechnology's upcoming special issue on environmental biotechnology.

As chemical pesticides raise concerns over insect resistance, collateral environmental damage, and human exposure risks, transgenic methods are becoming an attractive option for future pest control.

For instance, certain strains of corn and cotton have been modified to produce protein toxins from the bacterium Bacillus thuringiensis (Bt) that poison certain worms, beetles, and moths. RNA interference adds another degree of subtlety, by instead shutting down essential genes in pests that consume crops.

"RNA interference-based pest control can provide protection at essentially no cost because once the variety is developed, the plant can just go on using it instead of needing additional applications of insecticide," says co-senior author Ralph Bock, a director at the Max Planck Institute of Molecular Plant Physiology in Germany.

An RNA interference strategy could also address environmental and human toxicity questions around chemical pesticides. "When we target a key pest with RNA interference technology, what we are really hoping for is to see a big reduction in overall insecticide use," says co-senior author David Heckel, a director at the Max Planck Institute of Chemical Ecology.