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It Takes More Than a Green Thumb to Grow Plants in Space
Arabidopsis plants imaged in white ligh, left, and Green Fluorescent Protein, GFP, excitation illumination, right. Arabidopsis plants imaged in white light (left) and Green Fluorescent Protein (GFP) excitation illumination, right. Image credit: Anna-Lisa Paul, Ph.D. and Robert Ferl, Ph.D., Department of Horticultural Sciences, University of Florida.
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TAGES petri plate condensation TAGES petri plate condensation. Image credit: Bionetics Corporation, Kennedy Space Center.
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Astronaut Leland Melvin holding the Kennedy Space Center Fixation Tubes, KFTs, containing a TAGES harvest. Astronaut Leland Melvin holding the Kennedy Space Center Fixation Tubes, or KFTs, containing the TAGES harvest of 1A GUS plants in the Red Banded KFT (left) and Green Florescent Protein, or GFP, plants in the Green Banded KFT (right). Image credit: NASA
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Think you have a green thumb? Try growing plants in space.

The Transgenic Arabidopsis Gene Expression System, or TAGES, experiment on the International Space Station is aimed at learning how to do just that.

Microgravity, or near weightlessness, gives plants a unique environment in which to grow -- unlike any they experience on Earth. The TAGES experiment will determine how plants react to this novel, and potentially stressful, situation.

The experiment developed by Robert Ferl and Anna-Lisa Paul at the University of Florida in Gainesville contains genetically engineered plants with reporter genes. These genes "report" back on the various reactions of the plants by using sensors sensitive to the stresses of spaceflight. These biological sensor plants are referred to as TAGES.

"Understanding gene expression responses in these plants can help us learn how they survive and adapt to an environment they could never encounter on Earth," said Anna-Lisa Paul, one of two co-principal investigators. Gene expression is the process by which a gene's coded information is converted into the structures operating in the plant cells.

Changes in the plants can be monitored in real time while on orbit. The reporter genes are visualized as a green fluorescent glow by imaging systems built into the hardware carrying the experiment. The fluorescence is due to a green protein in the reporter gene. Fluorescent images captured by the specialized hardware are transmitted from the space station to the ground during the plants' growth cycle. TAGES is a first-of-its-kind experiment that allows investigators to receive gene expression telemetry from space. Some of the plants are being harvested on orbit and preserved for return to Earth. In-depth biochemical analyses will be conducted to examine changes in gene expression of all of the plant genes – not just the ones represented by the special reporter genes.

"Plants form an important part of spaceflight advanced life support concepts, so knowing what it takes for plants to grow well and adapt to spaceflight will inform us of their potential roles in future spaceflight applications such as food production and water and air revitalization," added Robert Ferl, Paul's co-principal investigator for TAGES.

The plants harvested in space will return to Earth on space shuttle Discovery STS-131’s mission targeted to launch in April. It will take about a year to fully analyze the plants and their gene expression.
by Lori Meggs, AI Signal Research, Inc.
NASA's Marshall Space Flight Center