Crops That Shut Down Pests' Genes

Monsanto is developing genetically modified plants that use RNA interference to kill the insects that eat them.

Researchers have created plants that kill insects by disrupting their gene expression. The crops, which initiate a gene-silencing response called RNA interference, are a step beyond existing genetically modified crops that produce toxic proteins. Because the new crops target particular genes in particular insects, some researchers suggest that they will be safer and less likely to have unintended effects than other genetically modified plants. Others warn that it is too early to make such predictions and that the plants should be carefully tested to ensure that they do not pose environmental problems. But most researchers agree that it's unlikely that eating these plants would have adverse effects on humans.

RNA interference occurs naturally in animals ranging from worms to humans. It's a process whereby double-stranded RNA copies of specific genes prevent cells from translating those genes into proteins. The new genetically modified plants carry genes for double-stranded RNA targeted to particular insect genes. Two papers published concurrently in Nature Biotechnology this week show that in some insects, eating double-stranded RNA is enough to cause gene silencing. This is surprising: in previous research, RNA interfered with organisms' gene expression only when it was injected.