The next great GMO debate: RNA biotech
Deep inside its labs, Monsanto is learning how to modify crops by spraying them with RNA rather than tinkering with their genes.
THE Colorado potato beetle is a voracious eater. The insect can chew through 10 square centimeters of leaf a day, and left unchecked it will strip a plant bare. But the beetles I was looking at were doomed. The plant they were feeding on—bright green and carefully netted in Monsanto’s labs outside St. Louis—had been doused with a spray of RNA.
The experiment took advantage of a mechanism called RNA interference. It’s a way to temporarily turn off the activity of any gene. In this case, the gene being shut down was one vital to the insect’s survival. “I am pretty sure 99 percent of them will be dead soon,” said Jodi Beattie, a Monsanto scientist who showed me her experiment.
The discovery of RNA interference earned two academics a Nobel Prize in 2006 and set off a scramble to create drugs that block disease-causing genes. Using this same technology, Monsanto now thinks it has hit on an alternative to conventional genetically modified organisms, or GMOs. It can already kill bugs by getting them to eat leaves coated with specially designed RNA. And if the company succeeds in developing sprays that penetrate plant cells, as it’s attempting to, it could block certain plant genes, too. Imagine a spray that causes tomatoes to taste better or helps plants survive a drought.
Monsanto isn’t the only one working on genetic sprays. Other large agricultural biotech companies, including Bayer and Syngenta, are also investigating the technology. The appeal is that it offers control over genes without modifying a plant’s genome—that is, without creating a GMO.
That means sprays might sidestep much of the controversy around agricultural biotechnology. Or so companies hope. What’s certain is that a way to accomplish the goals of genetic engineering without having to develop a GMO could bring commercial rewards. Sprays might be quickly tailored to do battle with an insect infestation or a new type of virus. Not only could this be faster than creating new GM crops, but the gene-silencing effects of RNA interference last only a few days or weeks. That means you might spray on traits such as drought resistance in times of water shortage without affecting the plant’s performance in times of normal rainfall.
Beattie showed me a large glass jar in which dried, purified RNA glistened like crumbled packing peanuts. A few years ago, this much RNA might have cost $1 million, one reason few would have thought to spray it from tractors rumbling through rows of corn. But the cost of making RNA has plummeted. Monsanto estimates that it now costs $50 a gram. A tenth that amount, the company says, is potent enough to kill 100 percent of beetles on an acre of plants.
At Monsanto I met Robb Fraley, the company’s chief technology officer, who oversees a research staff of 5,000. Three years ago Fraley designated the RNA sprays as one of Monsanto’s new areas for product development. He thinks that within a few years they will “open up a whole new way to use biotechnology” that “doesn’t have the same stigma, the same intensive regulatory studies and cost that we would normally associate with GMOs.” He’s told people he thinks the tools are “incredible” and “breathtaking” and that “of all the platforms we are working on, this is the one that reminds me the most of the early days of biotech.”
It was Fraley who made Monsanto’s first GM plants in the 1980s—petunias resistant to a plant poison. Today, Monsanto has revenues of about $9 billion a year from GM seeds for crops that produce the insect toxin Bt or resist the weed killer Roundup. GM corn, soy, and cotton plants now spread across 180 million hectares. And it has generated a public controversy just as vast. To its strongest critics, the company is simply “Monsatan.”
But with the RNA spray technology, which Monsanto calls BioDirect, the company may have found something that will bedevil opponents. The sprays are made from a ubiquitous molecule that degrades quickly in soil. They can be genetically precise enough to kill potato bugs but spare their ladybug cousins. And so far, consuming RNA molecules appears no more toxic to people than drinking a glass of orange juice. As Monsanto put it in a letter to U.S. regulators, “humans have been eating RNA as long as we have been eating.”
Public opposition, regulations, and the slow pace of plant breeding mean that on average, bringing a new GM crop to market costs more than $100 million and takes around 13 years. But imagine you wanted to fight a plant virus, says James Carrington, head of a Missouri nonprofit called the Danforth Plant Science Center and an advisor to Monsanto. “If you can gain control with a spray, you can envision a product that can change very rapidly, that you can test faster, experiment with faster, and bring to market faster,” he says. “You could respond to issues as they arise.”
Not everyone is convinced, though, that applying RNA will be commercially feasible or any less controversial than genetic modification. “The public is not accepting GMOs, and this could be more alarming. People are going to say you are taking the RNA and spraying this in the open,” says Kassim Al-Khatib, a plant physiologist at the University of California, Davis. “The acceptance of biotech has to be there before you can deliver another approach. This isn’t a technology for tomorrow. It’s for the day after tomorrow.”…..
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