Tomatoes

Nexgen Plants has received approval from USDA to conduct field trials of six gene-edited, virus-resistant tomato lines.

Gene-edited tomatoes that are resistant to common viruses can be introduced into the U.S. without coming under federal regulations for genetically engineered plants.

The USDA has determined that six tomato lines developed by Nexgen Plants of Australia aren’t potential plant pests and thus don’t fall under the agency’s jurisdiction for regulating biotech crops.

Nexgen altered the tomatoes with “particle bombardment” of gene sequences that allows the plants to detect and destroy the tomato spotted wilt virus and cauliflower mosaic virus.

“We only use the native DNA of the plant, we don’t insert any foreign DNA,” said Philippe Herve, the company’s CEO.

Tomatoes and other plants naturally rely on molecules of ribonucleic acid, or RNA, to recognize and chop up invading sequences of virus DNA, but the pathogen evolves to circumvent this mechanism.

“The plants need time to develop another defense if the virus mutates,” Herve said. “It’s kind of an endless battle between the virus and the plant.”

Instead of waiting for the process to occur naturally, Nexgen assembles components of existing tomato DNA to target the newest strains of the virus, accelerating the development of resistance, he said.

Particles of gold coated with this reconfigured tomato DNA were repeatedly blasted into the plant’s cells. The six virus-resistant lines were created when tomato plants naturally integrated Nexgen’s template into their genes to fight off the viruses.

Traditionally, farmers have warded off virus infections by targeting the insects that spread the diseases.

Now, however, they are using fewer insecticides, increasing the likelihood of virus transmission, Herve said.

Nexgen is simply providing the tomato plants with an up-to-date version of the DNA template needed to fight the virus without interfering with the defense mechanism itself, he said.

Such changes to plant DNA can be accomplished with the use of agrobacterium, which is considered a plant pest, but that would place the tomato lines under USDA regulations for genetic engineering, Herve said.

By relying on particle bombardment and native DNA, the company can now conduct field trials within the U.S. without undergoing the federal deregulation process, he said.

However, Nexgen is a research company rather than a plant breeder, and so would need to find a company with that expertise to commercialize the virus-resistant traits, Herve said. “We need to find a partner to bring this technology to market.”

The Center for Food Safety, a nonprofit that advocates stricter federal oversight of biotechnology, believes the type of gene-editing performed by Nexgen should be regulated by the USDA, said Bill Freese, the group’s science policy analyst.

“The small interfering RNAs that are generated in these tomatoes may well have off-target effects — meaning that they may silence genes other than those which are targeted to achieve virus resistance, with unpredictable effects on plant physiology,” Freese said in an email.

I've been working at Capital Press since 2006 and I primarily cover legislative, regulatory and legal issues.

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