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A Clue to Growing Food on Mars Someday

December 8, 2015
With a Rotten Tomatoes score of 93%, the Martian has become a box office hit, grossing over $571 million worldwide. During a manned mission to Mars, Astronaut Mark Watney (Matt Damon) is presumed dead after a fierce storm and left behind by his crew. With a limited amount of supplies, he must find a way to survive on the hostile planet while members of NASA and fellow crew members work to bring him back home. 

The conditions on Mars aren't conducive for human survival making for a thrilling science fiction plot. But what if we could make the conditions on Mars work for us? What kind of a movie plot would that look like? This idea may be realized sooner than we think.

Scientists in Australia have identified a DNA sequence in an ancient tobacco plant that enables it to survive in the country’s remote Outback. The discovery could offer clues to growing plants someday in another harsh environment—on the planet Mars, they said.

Reported on by Rachel Pannett of the Wall Street Journal: "Nicotiana benthamiana, known as pituri to indigenous Aboriginal tribes who use it as chewing tobacco, underwent a genetic mutation roughly 750,000 years ago to help it thrive despite the extreme conditions of the Outback, says Peter Waterhouse, a plant geneticist at Queensland University of Technology."

To focus the bulk of its energy on reproduction in an environment with very little rainfall, N. benthamiana, a relative of the common tobacco plant, lost its immune system, the natural protection that defends most living organisms against infection. Australia’s Outback region is so remote and arid that few infections exist there...

Dr. Waterhouse, who helped isolate the gene responsible for shutting down the plant’s immune system, says the discovery could eventually be applied to growing plants in sterile artificial environments in space, where there are no known diseases that could wipe out crops, and plants will need to grow quickly to survive.
“In most places [a faulty immunity gene] is going to be a pretty useless trait because it’s going to be wiped out by disease,” Dr. Waterhouse says. “In places like space where there are no pathogens, if you were growing your own plants you could dispense with the waste of having these defenses.”

To test their findings, the researchers took another variety of N. benthamiana that grows in coastal parts of Australia and disabled the gene responsible for the plant’s disease-defense mechanisms. The genetically modified plant produced seeds that were about 50% bigger and about twice the weight of the original, Dr. Waterhouse says. He says this is because plants use a lot of energy defending themselves against pathogens. Once they’re no longer trying to fight disease, they’re able to grow big faster, helping them survive harsh environments, the researchers found.

The variety of N. benthamiana that lacks an immune system has long been familiar to scientists, though the specific DNA sequence responsible for this characteristic wasn’t entirely clear. Geneticists have widely used it as a model plant for testing viruses and vaccines. Without an immune system, the plant doesn’t reject genes transplanted from other species as foreign. The experimental Ebola drug ZMapp, for example, is produced in the leaves of tobacco plants descended from the mutated Australian plant.

Dr. Waterhouse discovered the mutated gene while tracing the history of the plant. It was discovered by John Cleland, a scientist at the University of Adelaide, in the Granites gold mining area on the border of Western Australia and the Northern Territory in 1936. The seeds were sent to an American botanist, Thomas Harper Goodspeed, several years later and have been passed from lab to lab around the world because of the plant’s unique properties, Dr. Waterhouse says.