This Insect Has Plant DNA in Its Genome

Whiteflies have a gene only found in plants that appears to allow the tiny insects to withstand plants’ chemical defenses

whitefly on a leaf
A tiny, aphid-like whitefly sitting on a leaf. Jixing Xia and Zhaojiang Guo

A small, aphid-like insect called a whitefly has plant DNA lurking in its genome—and it’s among the first known instances of gene transfer from plant to insect, reports Heidi Ledford for Nature.

The gene in question is no slouch either, as it appears to enable the insects to feed on plants loaded with natural toxins, according to the new study published last week in the journal Cell. This fateful transference of genetic material occurred at least 35 million years ago and looks to be part of the genetic toolkit that make whiteflies such a formidable agricultural pest, reports Jonathan Lambert for Science News.

“Ten or 20 years ago no one thought that this kind of gene transfer was possible,” Roy Kirsch, a chemical ecologist at the Max Planck Institute for Chemical Ecology who wasn’t involved in the study, tells Science News. “There are so many barriers a gene must overcome to move from a plant to an insect, but this study clearly shows that it happened, and that the gene provides a benefit to whiteflies.”

How exactly the whitefly got plant DNA into its genome is still unknown, but the gene transfer event may have involved viruses, reports Donna Lu for New Scientist. In this scenario, a virus going from whiteflies to plants or vice versa takes on some plant DNA. Then, when the virus infected the whitefly, the plant DNA spread and was eventually incorporated into the bug’s genome.

“[Some] viruses basically incorporate their own genome into the cells of their hosts,” Ted Turlings, an entomologist at the University of Neuchâtel in Switzerland and co-author of the study, tells New Scientist.

“This is an extremely rare event, but when you’re talking about billions of insects and plants interacting over millions of years, it becomes more possible,” Turlings tells Science News. This type of gene transfer may in fact be “an important mechanism for pests to gain abilities to deal with plant defenses,” Turlings adds.

Besides revealing a fascinating piece of biology, the findings may also help protect future crops from the sap-sucking whitefly, per Nature. Preliminary experiments suggest that turning the pilfered plant gene off makes the insects susceptible to plant toxins.

“This exposes a mechanism through which we can tip the scales back in the plant’s favor,” Andrew Gloss, an evolutionary ecologist at the University of Chicago who was not involved in the study, tells Nature. “It’s a remarkable example of how studying evolution can inform new approaches for applications like crop protection.”