A pernicious agricultural pest owes some of its success to a gene pilfered from its plant host millions of years ago. The finding, reported recently in the journal Cell, is the first known example of a natural gene transfer from a plant to an insect, writes Heidi Ledford in an article for Nature.
It also explains one reason why the sweet potato whitefly Bemisia tabaci is so adept at munching on crops: the gene that it swiped from plants long ago 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 favour,” says Andrew Gloss, who studies plant–pest interactions at the University of Chicago in Illinois. “It’s a remarkable example of how studying evolution can inform new approaches for applications like crop protection.”
The diminutive whitefly — which is more closely related to aphids than to flies — wreaks agricultural havoc around the world. Bemisia tabaci is among the most destructive plant pests: whiteflies sup sugary sap from hundreds of types of plant, all the while excreting a sticky, sweet substance called honeydew that serves as a breeding ground for mould. Whiteflies are also vectors for more than 100 pathogenic plant viruses.
As researchers sequence more genomes, it’s possible that they’ll uncover more examples of gene transfer between plants and animals, says Gloss. “Insects taking the genes from the plants themselves is just that last bit of the arsenal that we hadn’t found yet,” he says.