One Little Seed, Eight Special Genes

Monsanto plans a super corn seed to ward off weeds and bugs

If a seed is a little package of life, then the genes inside it are life's instruction manual. Monsanto's (MON) expertise is rewriting those instructions to make fully grown plants do unexpected things, like survive a bath in herbicide and kill root-eating beetles. The company's most ambitious project yet, a partnership with rival Dow AgroSciences (DOW), aims to create a corn seed with eight specially tailored genetic traits, surpassing Monsanto's three-trait corn available now.

Due out in 2010, the so-called SmartStax seed will contain six genes that ward off bugs and two genes that help plants ward off pesticides. The goal is an all-in-one seed for farmers to fight the twin plagues of insects and weeds. The company expects a blockbuster, projecting that SmartStax eventually could be planted on 100 million acres worldwide.

The key scientific challenge is not simply getting eight foreign genes into a plant cell. It's getting this genetic cut-and-paste job to produce a healthy, functioning plant. That doesn't require theoretical genius so much as hours of painstaking labor.

When scientists want to create a seed with a particular trait—say, a toxin that kills caterpillars—they'll place a corn embryo in a petri dish. On it, they'll pour a solution of agrobacterium, a soil bacteria that acts as a natural genetic ferry. The agrobacterium carries the gene for the toxin into the cells of the corn embryo.

There's no guarantee this genetic transfer will work. Some cells sprout into plantlets, but others grow without the right properties. "It's random," says Eric Sachs, Monsanto's global head for scientific affairs. So a researcher performs the maneuver many times and identifies the cells that work. Those few are cultivated in temperature- and light-controlled chambers.

Once the corn plants with the right traits are created through this process, they're bred together. To make the eight-trait seed, four separate lines of corn, each with two of the desired genetic traits inside, are crossed.

The joint venturers are hoping that SmartStax will allow farmers to plant more gene-modified crops. Right now, the worry is that bugs will develop resistance to the pesticide in the corn. So the Environmental Protection Agency requires farmers to sow 20% of their plots with regular corn. That ensures some normal pests survive. Otherwise a breed of hard-to-kill superbugs would evolve. But Monsanto argues that SmartStax's multiple bug-killers are so effective that no bugs will be able to develop resistance. So it asked the EPA to reduce the refuge requirement to 5%. But entomologists have concerns about the proposal, and approval isn't a sure thing.

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