Transgenic Arabidopsis Gene Expression System (TAGES) - 02.12.14
ISS Science for Everyone
Science Objectives for Everyone Transgenic Arabidopsis Gene Expression System (TAGES) investigation is one in a pair of investigations that use the Advanced Biological Research System (ABRS) facility. TAGES uses Arabidopsis thaliana, thale cress, with sensor promoter-reporter gene constructs that render the plants as biomonitors, or an organism used to determine the quality of the surrounding environment, using real-time nondestructive Green Fluorescent Protein imagery and traditional postflight analyses.
Science Results for Everyone
The Transgenic Arabidopsis Gene Expression System (TAGES) experiment adds special genes to turn a plant into a monitor to measure the quality of the surrounding environment. Fluorescent markers on these genes allow scientists to study root development of Arabidopsis (a cress plant) grown on the ISS, showing that directional light in microgravity skews root growth to the right, rather than straight down from the light source. This skewing, previously thought to be gravity-dependent, is therefore gravity-independent. Root growth patterns on board the ISS mimic that of plants grown at a 45 degree angle on Earth. Space flight appears to slow the rate of the plant’s early growth as well.
Bionetics Corporation, Cape Canaveral, FL, United States
Kennedy Space Center, , FL, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
October 2009 - September 2010
Previous ISS Missions
TAGES is scheduled to arrive on the ISS during the 17A mission.
- The TAGES research is needed to help understand how plants perceive stresses in the space flight environment such as drought, inadequate light, or uneven temperature.
- Traditionally, understanding plant stress at the genetic level required killing the plant and analyzing it using chemicals and microscopes. The TAGES experiment will use a new real-time imaging technique that does not kill the plants, making it possible to follow the development of stress in a plant over time.
- The new technique uses a gene inserted into the genome of the plant. When a plant perceives a certain stress, it expresses this gene. The gene expression can be viewed with a special camera. When such a plant is illuminated with a certain frequency of blue light, the plant fluoresces green.
- Such genetically modified plants and imaging tools could be used as biosensors for characterizing plants in other spacecraft environments.
The Transgenic Arabidopsis Gene Expression System (TAGES) investigation will provide an understanding of physiological processes such as gene expression, metabolism and general plant development that are affected in plant systems exposed to space flight.
TAGES investigation seeks to understand space flight induced molecular changes in Arabidopsis thaliana gene activity. A series of transgenic plants (plants containing foreign DNA integrated into their genome) have been designed for the TAGES investigation. The plants carry sensor promoter-reporter gene constructs that are capable of monitoring a variety of environmental and developmental influences, thereby rendering the plants biomonitors of their environment. Arabidopsis thaliana is the plant of choice to house the sensor promoter-reporter gene constructs due to its well-understood genome and relatively short seed-to-seed cycle, as well as having been the focus of several space flight studies on previous plant experiments conducted during ISS, Mir and Space Shuttle missions.
The first group of biomonitors for TAGES consists of plants with alcohol dehydrogenase (Adh) sensor promoter and beta-glucuronidase (GUS) reporter gene constructions. The second group of biomonitor plants incorporates the Green Fluorescent Protein (GFP) reporter gene construction. Two primary goals have been identified for the TAGES experiment: 1) confirm and extend data from an experiment conducted on STS-93 in 1999 by utilizing the GUS reporter gene system, 2) test the fidelity and practicality of the GFP reporter gene system in comparison to GUS.
The GFP Imaging System (GIS) will demonstrate a powerful real-time, non-destructive analytical tool that can be used to assess the status of a target organism. This device will help to revolutionize space-based biological research by ultimately eliminating the resource-intensive need to return biological material to Earth for postflight analysis. This advanced technique can be applied to a host of model organisms engineered with the GFP gene construct including plants, microbes, and nematodes.
TAGES along with the ABRS hardware demonstrates the capabilities of providing the correct environment for plant growth onboard spacecraft. For future long-duration exploration, crews will need to be able to grow plants for a variety of applications.
The miniaturization of the Green Fluorescent Protein (GFP) imaging apparatus as a requirement for this spaceflight investigation has produced a device that is easily transportable and may be used as a means for conducting in situ analysis of appropriately genetically prepared biomonitors.
TAGES requires a controlled environment provided by the ABRS facility which also provides images that are downlinked to the ground teams. The crew is responsible for harvesting, reinitialization, water refill and changing out the air filter. After harvesting, parts of the samples are chemically preserved and stored in the Minus Eighty-Degree Laboratory Freezer for ISS (MELFI).
The crewmembers are responsible for refilling the water reservoir by using a syringe to transfer approximately 60-mL of water from the ISS potable water source to each of two quick disconnect fittings associated with the two reservoirs inside the ABRS. Air filter change out is performed by opening the front hatch of the ABRS locker, loosening a Velcro restraining strap, and pulling each of the two filters off of the back side of the hatch. There are blind mate connectors on the back side of each filter.
For the harvesting of the TAGES A. thaliana plants, crewmembers remove one root tray from the ABRS to access petri plates containing the plants. Plants are harvested from petri plates into the KFTs. The TAGES GUS harvest occurs at L+5 days. The TAGES GFP plants are autonomously imaged within the ABRS facility. About every 2 weeks, TAGES GFP plants are harvested and other plants within ABRS are moved into the field of view of the GFP camera. Some of these KFTs require a day to perfuse the plant tissues before placing in cold stowage at -68 degrees C or colder until return. During the harvests, some petri plates are moved into or out of the field of view of the autonomous GFP Imaging System (GIS) attached to the root tray. TAGES plants for runs 2 and 3 are launched in ambient stowage and transferred to ABRS on ISS.
TAGES analyzed root morphology of Arabidopsis grown on Petri plates while on board the ISS, and global gene expression patterns in the plants preserved on orbit and returned to Earth. Imaging hardware delivered plant images from the ISS providing science without returned samples. These images revealed that in the absence of gravity with the presence of directional light, roots grew by skewing to the right, as opposed to growing straight down the plate away from the light source. This skewing phenomenon was previously thought to be gravity dependent, however the skewed root growth of the TAGES plants on orbit showed that this process is gravity independent. Root growth patterns in microgravity mimic those of ground studies where plants are grown along the surface of agar plates held at a 45 degree slant. Space flight was also found to retard the rate of early Arabidopsis growth (Paul 2012).
Paul A, Amalfitano CE, Ferl RJ. Plant growth strategies are remodeled by spaceflight. BMC Plant Biology. 2012; 12(1): 232.
Ground Based Results Publications
Schultz ER, Kelley KL, Paul A, Ferl RJ. A method for preparing spaceflight RNAlater-fixed Arabidopsis thaliana (Brassicaceae) tissue for scanning electron microscopy.Applications in Plant Sciences. 2013 August; 1(8): 1300034. DOI: 10.3732/apps.1300034.
Paul A, Ferl RJ. Molecular Aspects of Stress-Gene Regulation During Spaceflight. Journal of Plant Growth Regulation. 2002; 21: 166-176. DOI: 10.1007/s003440010050.
Paul A, Ferl RJ. Using Green Fluorescent Protein (GFP) Reporter Genes in RNALater Fixed Tissue.Gravitational and Space Biology. 2011; 25(1): 40-43.
Wyatt SE, Kiss JZ, Kiss JZ. Plant Tropisms: From Darwin to the International Space Station. American Journal of Botany. 2013; 100(1): 1-3. DOI: 10.3732/ajb.1200591. PMID: 23281390.
Roux SJ. Root waving and skewing - unexpectedly in micro-g. BMC Plant Biology. 2012; 12(1): 231. DOI: 10.1186/1471-2229-12-231. PMID: 23217095.
Advanced Biological Research System (ABRS) Green Fluorescent Protein (GFP) Imaging System prototype. Image provided by The Bionetics Corporation at Kennedy Space Center.
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Arabidopsis plants imaged in white light (left) and Green Fluorescent Protein (GFP) excitation illumination, right. Image provided by Anna-Lisa Paul, Ph.D. and Robert Ferl, Ph.D., Department of Horticultural Sciences, University of Florida.
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TAGES principal investigators Dr. Ferl and Dr. Paul with their plants. Image provided by The Bionetics Corporation at Kennedy Space Center.
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TAGES petri plate condensation. Image provided by The Bionetics Corporation at Kennedy Space Center.
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NASA Image: ISS021E030731 - Astronaut Leland Melvin holding the Kennedy Space Center Fixation Tubes (KFTs) containing the TAGES harvest of 1A GUS plants in the Red Banded KFT (left) and Green Florescent Protein (GFP) plants in the Green Banded KFT (right) during the STS-129/ULF3 mission during the ISS Expedition 21.
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NASA Image: ISS022E011304 - NASA astronaut Jeffrey Williams, Expedition 22 commander, conducts a daily status check of the Advanced Plant Experiments on Orbit (APEX) experiment in the Kibo laboratory of the International Space Station. During each check, Williams looks for health and color of the plants, since the Cambium plants are removed from the Advanced Biological Research System (ABRS). When completed, the APEX-Cambium payload in conjunction with the NASA-sponsored Transgenic Arabidopsis Gene Expression System (TAGES) will determine the role of gravity in Cambium wood cell development and demonstrate non-destructive reporter gene technology and investigate spaceflight plant stress. APEX-Cambium provides NASA and the ISS community a permanent controlled environment capability to support growth of various organisms (i.e. whole plants).
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