By Paul Kimpel Daily University Science News
 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."
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