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http://www.universetoday.com/am/publish/grow_plants_by_relieve_anxiety.html?882005

Trick Plants to Grow on Mars

Summary - (Aug 8, 2005) If humans are going to live on Mars, we're going
to need to learn how to grow plants in the planet's thin atmosphere, poor
soil, severe cold, and total lack of water. This environment will put
plants into a severe state of stress and shut down their metabolism, but
NASA scientists think they've got strategies to help them cope. By
introducing genes from extremophile microbes that can withstand severe
changes in environment, scientists are hoping to modify plants so they
won't shut down their metabolism in response to stress.


Full Story -  Anxiety can be a good thing. It alerts you that something
may be wrong, that danger may be close. It helps initiate signals that get
you ready to act. But, while an occasional bit of anxiety can save your
life, constant anxiety causes great harm. The hormones that yank your body
to high alert also damage your brain, your immune system and more if they
flood through your body all the time.

Plants don't get anxious in the same way that humans do. But they do
suffer from stress, and they deal with it in much the same way. They
produce a chemical signal - superoxide (O2-) - that puts the rest of the
plant on high alert. Superoxide, however, is toxic; too much of it will
end up harming the plant.

This could be a problem for plants on Mars.

According to the Vision for Space Exploration, humans will visit and
explore Mars in the decades ahead. Inevitably, they'll want to take plants
with them. Plants provide food, oxygen, companionship and a patch of green
far from home.

On Mars, plants would have to tolerate conditions that usually cause them
a great deal of stress - severe cold, drought, low air pressure, soils
that they didn't evolve for. But plant physiologist Wendy Boss and
microbiologist Amy Grunden of North Carolina State University believe they
can develop plants that can live in these conditions. Their work is
supported by the NASA Institute for Advanced Concepts.

Stress management is key: Oddly, there are already Earth creatures that
thrive in Mars-like conditions. They're not plants, though. They're some
of Earth's earliest life forms-ancient microbes that live at the bottom of
the ocean, or deep within Arctic ice. Boss and Grunden hope to produce
Mars-friendly plants by borrowing genes from these extreme-loving
microbes. And the first genes they're taking are those that will
strengthen the plants' ability to deal with stress.

Ordinary plants already possess a way to detoxify superoxide, but the
researchers believe that a microbe known as Pyrococcus furiosus uses one
that may work better. P. furiosus lives in a superheated vent at the
bottom of the ocean, but periodically it gets spewed out into cold sea
water. So, unlike the detoxification pathways in plants, the ones in P.
furiosus function over an astonishing 100+ degree Celsius range in
temperature. That's a swing that could match what plants experience in a
greenhouse on Mars.

The researchers have already introduced a P. furiosus gene into a small,
fast-growing plant known as arabidopsis. "We have our first little
seedlings," says Boss. "We'll grow them up and collect seeds to produce a
second and then a third generation." In about one and a half to two years,
they hope to have plants that each have two copies of the new genes. At
that point they'll be able to study how the genes perform: whether they
produce functional enzymes, whether they do indeed help the plant survive,
or whether they hurt it in some way, instead.

Eventually, they hope to pluck genes from other extremophile microbes -
genes that will enable the plants to withstand drought, cold, low air
pressure, and so on.

The goal, of course, is not to develop plants that can merely survive
Martian conditions. To be truly useful, the plants will need to thrive: to
produce crops, to recycle wastes, and so on. "What you want in a
greenhouse on Mars," says Boss, "is something that will grow and be robust
in a marginal environment."

In stressful conditions, notes Grunden, plants often partially shut down.
They stop growing and reproducing, and instead focus their efforts on
staying alive-and nothing more. By inserting microbial genes into the
plants, Boss and Grunden hope to change that.

"By using genes from other sources," explains Grunden, "you're tricking
the plant, because it can't regulate those genes the way it would regulate
its own. We're hoping to [short-circuit] the plant's ability to shut down
its own metabolism in response to stress."

If Boss and Grunden are successful, their work could make a huge
difference to humans living in marginal environments here on Earth. In
many third-world countries, says Boss, "extending the crop a week or two
when the drought comes could give you the final harvest you need to last
through winter. If we could increase drought resistance, or cold
tolerance, and extend the growing season, that could make a big difference
in the lives of a lot of people."

Their project is a long-term one, emphasize the scientists. "It'll be a
year and a half before we actually have [the first gene] in a plant that
we can test," points out Grunden. It'll be even longer before there's a
cold- and drought-loving tomato plant on Mars-or even in North Dakota. But
Grunden and Boss remain convinced they will succeed.

"There's a treasure trove of extremophiles out there," says Grunden. "So
if one doesn't work, you can just go on to the next organism that produces
a slightly different variant of what you want."

"Amy's right," agrees Boss. "It is a treasure trove. And it's just so
exciting."




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