A pernicious agricultural pest owes some of its success to a gene pilfered from its plant host millions of years ago. 

The finding, reported [March 25]  in Cell, is the first known example of a natural gene transfer from a plant to an insect. It also explains one reason why the whitefly Bemisia tabaci is so adept at munching on crops: the gene that it swiped from plants enables it to neutralize a toxin that some plants produce to defend against insects.

Early work suggests that inhibiting this gene can render the whiteflies vulnerable to the toxin, providing a potential route to combating the pest. “This exposes a mechanism through which we can tip the scales back in the plant’s favor,” says [researcher] Andrew Gloss.

To test the hypothesis, the team engineered tomato plants to produce a double-stranded RNA molecule capable of shutting down expression of the whitefly gene. Nearly all of the whiteflies that subsequently fed on these doctored tomato plants died.

That result suggests a new means of targeting whiteflies, says Jonathan Gershenzon, a chemical ecologist at the Max Planck Institute for Chemical Ecology in Jena, Germany. “It offers an enormous chance to be specific,” he says. “You could keep the whiteflies away but not harm beneficial insects such as pollinators.”

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