Modified Plant May Send Glowing Messages From Mars
In what reads like a story from a 1950s science fiction magazine, a team of University of Florida scientists has genetically modified a tiny plant to send reports back from Mars in a most unworldly way: by emitting an eerie, fluorescent glow.
If all goes as planned, 10 varieties of the plant could be on their way to the Red Planet as part of a $300 million mission scheduled for 2007.
The plant experiment, which is funded by $290,000 from NASA's Human Exploration and Development in Space program, may be a first step toward making Mars habitable for humans, said Rob Ferl, assistant director of the Biotechnology Program at UF.
Ferl and a team of molecular biologists chose as their subject the Arabidopsis mustard plant. They picked it, Ferl said, because of three attributes that make it ideally suited for the Mars mission: Its maximum height is 8 inches, its life cycle is only one month and its entire genome has been mapped. Moreover, in December 2000 it became the first plant to have its genetic sequence completed.
To create the glow, the team will insert "reporter genes" into varieties of the plant, which will express themselves by emitting a green glow under adverse conditions on Mars. Each reporter gene will react to an environmental stressor such as drought, disease or temperature. For example, one version will glow an incandescent green if it detects an excess of heavy metals in the Martian soil; another will turn blue in the presence of peroxides.
In fact, one of the reporter genes itself is somewhat otherwordly, having come from the depths of the ocean.
"What makes the plants glow blue is a protein derived from an incandescent jellyfish whose DNA is spliced into the mustard plant," Ferl said. "The implanted DNA then synthesizes the iridescent blue protein in the plant, which expresses itself under stress."
Ferl's team, in collaboration with Andrew Schuerger, a manager of Mars projects at the Kennedy Space Center-based Dynamac Corp., is competing with other biologists to receive the NASA contract for the Mars trip.
But both men, who also are professors at UF's Institute of Food and Agricultural Sciences, have worked with NASA before. In 1999, Ferl sent 40 reporter-gene plants into orbit aboard the space shuttle. On that flight, gravity had an adverse effect on the plants' ability to utilize water, a condition called "space adaptation syndrome."
The scientists are using that experience to engineer smarter plants.
"Just like humans, plants must learn how to adapt to a new environment," Ferl said. "We are using genetics to create plants that have the ability to give us data we can use to help them survive."
The 2 1/2-year Mars mission -- nine months traveling 286 million miles each way and one year stationed on the planet -- would work like this: The seeds of the plant would make the trip aboard a spacecraft similar to NASA's Mars Odyssey, which was launched April 7. Upon arrival, the landing vehicle's robot would scoop up a portion of Martian soil, and the scientists will analyze it using the robot and a specialized camera. After modifying the soil with fertilizers, buffers and nutrients, the scientists will germinate the seeds and grow the plants in a miniature greenhouse on the landing vehicle.
Despite working with alien soil they know little about, the biologists are optimistic about the experiment.
"I'm confident we can grow plants if we know the pH levels and the oxidizing agents in the Martian soil," Schuerger said. "We'll test the soil before planting, and then we can raise or lower pH, flush excess salts and add nutrients as needed."
As for long-term plans, Ferl and Schuerger have worked together on a concept called "terra-forming" or "ecosynthesis," which would use plants to reduce the carbon dioxide in the Martian atmosphere and produce oxygen for life processes. Although the plants are genetically engineered to detect -- and then adapt to -- certain environmental stressors, terra-forming presents additional obstacles.
Schuerger said that on Mars, daily temperatures range from a high of 45 degrees Fahrenheit at noon to a low of minus 170 degrees at night. Also, the planet's moisture content is 0.3 percent, which is extremely low.
But Ferl, Schuerger and the rest of the team are taking all bettors.
"I have no doubt that we can get plants to survive on Mars," Ferl said. "When we do, we will have shown that Earth-evolved life is capable of thriving in distant worlds, and we will have set the stage for human colonization." - By Paul Kimpel
[Contact: Rob Ferl, Andrew Schuerger, Paul Kimpel]
30-Apr-2001 |
