Jellyplants on Mars

Ferl, Schuerger, and Chris McKay of NASA's Ames Research Centre. want to test the greenhouse concept by sending bioengineered plants to Mars on board a small NASA spacecraft - a "Mars Scout." They envision a seed-bearing lander that would scoop up a portion of Martian soil, add buffers and nutrients, then germinate the seeds to grow within a miniature greenhouse.

Thriving plants won't glow at all. They'll look like normal mustard. But plants struggling to survive will emit a soft green light, a signal to researchers that something is amiss. A camera onboard the lander would record the telltale glows and then relay the signal back to Earth. No humans are required on the scene - a big advantage for such a far away experiment.

The plants' designer genes consist of two parts: a sensor side to detect stress and a reporter side to trigger the glow.

The sensor side of the gene comes from the plant itself - Arabidopsis thaliana, a member of the mustard family also known as thale cress. Ferl and his colleagues picked Arabidopsis because three attributes suit it well for a Mars mission: Its maximum height is about 6 inches, so it can fit inside a small greenhouse, its life cycle is only six weeks, and its entire genome has been mapped. (For these same reasons Arabidopsis plants are already orbiting Earth on board the International Space Station as part of an independent experiment to learn how plants react to free fall.)

An artist's concept of a full-fledged Martian greenhouse, an essential part of any future human colony on the Red Planet.

The reporter side of the gene comes from Aequorea Victoria, a jellyfish common along the Pacific coast of North America. Aequorea live about six months, grow to 5 or 10 cm, and can glow soft-green along the rim of their bell-shaped bodies. Scientists aren't sure why they glow - Aequorea Victoria do not flash at each other in the dark, nor do they glow continuously. But the touch of a human hand, for example, can stimulate the jellyfish to "light up."

Once the sensor and the reporter gene fragments are stitched together, Ferl uses a bacteria to move the newly-constructed gene into the plant.