Genetically Altered Plant Attracts Bug "Bodyguards"

September 22, 2005

A new genetically modified plant uses chemical signals to invite predatory bugs to dine on unwelcome guests munching on its leaves.

The enhanced weed—a type of small mustard plant (Arabidopsis thaliana)—was able to summon bug "bodyguards" after researchers inserted a gene from a strawberry plant.

A. thaliana is the first plant to have its entire genome sequenced and so is regularly used in plant research. The genetically modified version of the weed may lead to a new method of crop pest control that reduces the need for chemical pesticides.

"This would deliver crop defense in the seed rather than in a spray," said John Pickett, head of biological chemistry at Rothamsted Research in Harpenden, England.

"This is the first time that a plant has been modified genetically to produce a [predator] attractant," he added. "Exploiting this process is really very important."

The study team reports that the genetically engineered plant was able to attract predatory mites (a small relative of spiders) that prey on plant-eating spider mites. The development is reported in tomorrow's issue of the journal Science.

Active Ingredient

Study co-author Harro Bouwmeester, a biochemist at Plant Research International at Wageningen University in the Netherlands, says the plant needed little genetic modification to introduce the chemical lure.

"It's very commonplace in the wild for plants to emit bodyguard-attracting compounds upon insect feeding," he said.

"Because this phenomenon is widespread in the plant kingdom, it means the machinery to produce these compounds is available in all plants. That means you just have to tap into existing pathways [in plant cells], and that can be done by the introduction of just one gene."

Bouwmeester says the active ingredient varies somewhat between plant species, but most bug attractants rely on complex compounds called terpenes.

"You will know terpenes from the smell of certain herbs like peppermint," he said. "Other plants also produce these compounds, but in lower concentrations so we don't smell them."

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