美国国家公共电台 NPR Is The Pentagon Modifying Viruses To Save Crops — Or To Wage Biological Warfare?（在线收听）

STEVE INSKEEP, HOST:

The Pentagon is funding some new research on insects and plant viruses. It says the goal is to protect agricultural crops. Some critics say it looks more like an attempt to make biological weapons. Here's NPR's Dan Charles.

DAN CHARLES, BYLINE: Jane Polston and I are walking over to some greenhouses at the University of Florida, where she teaches. She wants to show me how viruses infect plants, which she's been studying ever since she first learned about plant viruses back in college.

JANE POLSTON: I just fell in love.

CHARLES: With viruses.

POLSTON: Yeah. Isn't that weird?

CHARLES: We step inside the greenhouse. There's a smaller chamber here with walls of netting, and there's six tomato plants inside. They don't look too healthy. The leaves are wilted.

POLSTON: This is our tomato yellow leaf curl virus colony.

CHARLES: The tomato leaves look like they're covered with dandruff. But when Polston reaches in and moves a plant, the white particles come alive. They're tiny flies - whiteflies. They're also infected.

POLSTON: Because they're reared on these infected plants, I think probably all of them will have virus in them.

CHARLES: One of Polston's colleagues scoops up some of the flies and puts them in a cage with a healthy, uninfected tomato plant.

POLSTON: If you look carefully, you can see some of the whiteflies landing on the leaves.

CHARLES: And as soon as they start feeding on that plant, they're going to infect this plant with the virus.

POLSTON: Yeah, within about 15 minutes.

CHARLES: Polston spent years studying this triangle of insect, virus and plant, so she could figure out ways to disrupt it and stop the viruses from harming crops. But now she's getting ready to carry out a very different kind of experiment, in a different greenhouse, a super-secure one that they wouldn't let me go see. What's going on in that greenhouse is the brainchild of Blake Bextine, a program manager at the Defense Advanced Research Projects Agency, DARPA. He thinks there's a way to use this infectious triangle for good.

BLAKE BEXTINE: I thought, you know, this is a beautifully elegant system that puts genes into plants that causes negative effects. Why can't we turn the system upside down and use it to deliver positive traits into plants?

CHARLES: Bextine is giving money to Polston and several other groups of university researchers. Each one's using a different combination of insect and virus. The viruses will be genetically modified, so they can carry a new package of DNA - genes that can help the plant, maybe help corn survive a drought.

BEXTINE: If a drought is coming, we could actually use the insects to deliver viruses that carry with them the payload - that drought tolerance capability.

CHARLES: And the insects are supposed to be genetically altered, too, to make sure they all die off after they accomplish their mission. But all this talk of genetically modified insects delivering payloads sounds disturbing to Silja Voeneky, a law professor at the University of Freiburg in Germany.

SILJA VOENEKY: We asked whether the peaceful purposes of the program are sufficiently clear and plausible.

CHARLES: The stated purposes don't make a lot of sense, she says. If you're trying to protect your crops, just spray them. Why resort to genetically modified insects and viruses?

VOENEKY: It seems much easier to harm a plant with a technology than to make it more resilient.

CHARLES: You could imagine using insects and viruses to destroy somebody's crop, she says. And that is prohibited under the Biological Weapons Convention, which the U.S. and most other countries have signed. Blake Bextine from DARPA says those suspicions are not justified.

BEXTINE: We are not developing biological warfare agents. This is for the benefit of crops and the stability of our food supply.

CHARLES: The virus-loving scientist in Florida, Jane Polston, says, no, we're not making weapons. But new technology can be used in lots of ways which you often can't predict. Dan Charles, NPR News.

(SOUNDBITE OF EMANCIPATOR'S "MINOR CAUSE (ELIOT LIPP REMIX)")