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Experiment/Payload Overview

Brief Summary

Analysis of a Novel Sensory Mechanism in Root Phototropism (Tropi) studies Arabidopsis thaliana plants sprouting from seeds to gain insights into sustainable agriculture for future long-duration space missions.

Principal Investigator

John Z. Kiss, Ph.D., Miami University, Oxford, OH, United States

Co-Investigator(s)/Collaborator(s)

Melanie Correll, Ph.D., University of Florida, Gainesville, FL, United States

Richard Edelmann, Ph.D., Miami University, Oxford, OH, United States

Roger Hangarter, Ph.D., Indiana University, Bloomington, IN, United States

Payload Developer

Ames Research Center, Moffett Field, CA, United States

Sponsoring Space Agency

National Aeronautics and Space Administration (NASA)

Sponsoring Organization:

Exploration Systems Mission Directorate (ESMD)

ISS Expedition Duration:

October 2009 - September 2011

Expeditions Assigned

21/22, 23/24, 27/28

Previous ISS Missions

While Tropi is a new experiment, other studies of plant growth and development have been conducted on ISS.

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Experiment/Payload Description

Research Summary

• Analysis of a Novel Sensory Mechanism in Root Phototropism (Tropi) is a plant growth experiment that investigates how plant roots from Arabidopsis thaliana (thale cress) respond to varying levels of light and gravity.



• Plant growth under various gravity conditions (0g to 1.0g) is achieved using a rotating centrifuge.



• Plants grown are analyzed to determine which genes are responsible for successful plant growth in microgravity.



• This experiment helps gain insight into plant growth in space in order to help create sustainable life support systems for long term space travel.

Description

Analysis of a Novel Sensory Mechanism in Root Phototropism (Tropi) consists of dry Arabidopsis thaliana (thale cress) seeds stored in small seed cassettes. A. thaliana is a rapidly growing, flowering plant in the mustard family. The seed cassettes are contained inside the European Modular Cultivation System (EMCS). The seeds are installed into the EMCS dry and at ambient temperature until hydrated by an automated system of the EMCS. At specified times during the experiment; the plants are stimulated by different light spectrums and by different gravity gradients. The only operations required by the crew are to replace video tapes and harvest the plants following growth. Once the plants are harvested, they are stored in the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) until they are returned to Earth (STS-116 and STS-117). Investigators gather data from video-taped images of the plants, observing their roots as they undergo development in the EMCS, as well as conducting biochemical analyses of the returned plants.

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Applications

Space Applications

During long-term space exploration, it will be necessary to provide crewmembers with regenerative sources of food, as well as supplemental methods to recycle carbon dioxide into breathable oxygen. As new information about how plants grow in microgravity emerges, sustainable plant-based life support systems may be developed.

Earth Applications

Further understanding of how plants grow and develop at a molecular level can lead to significant advancements in agricultural production on Earth.

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Operations

Operational Requirements

During its ascent, Tropi requires no resources. The dry seeds are contained in five seed cassettes located in the EMCS. Once in orbit, the seeds are hydrated automatically. Video is taken throughout the experiment, allowing the ground team to evaluate and study the development of the plants. Ninety percent of the science return is based upon video analysis. The crew harvests the plants and stores the specimens in MELFI. They are also required to change out the video tapes.

Operational Protocols

Seed cassettes containing dried Arabidopsis thaliana seeds are initiated in the EMCS automatically. The EMCS introduces water to the seeds to activate growth. Video cameras record the growth and development of the plants. Once the plants are grown, the crewmembers harvest the plants and place them in the cold storage in MELFI. The plants are returned to the ground team for further study.

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Results/More Information

Preliminary analysis of the Tropi samples returned on STS-116 in December 2006 resulted in little or no yield of total RNA as indicated by the lack of discrete bands shown on gel A (image 6). However, samples returned on STS-117 in June 2007 resulted in good quality RNA as indicated by the discrete bands shown on gel B (image 6). For the samples returned on STS-117, a three-minute requirement was established; the seedlings in the Tropi cassettes would be transferred from MELFI to the JSC cold bag within three minutes on the ISS. This new requirement resulted in success of the cold transfer procedures and successful yield of RNA (John Kiss, "New Tropi Cold Procedures - Excellent RNA!" Email to Julie Robinson, ISS Program Scientist. 26 Nov. 2007). (Evans et al. 2009) The second run of Tropi occurred during Increment 22 and returned on STS-130 in April 2010. New procedures including space flight hardware that was off-gassed for a longer period, reduced seed storage in hardware, and removing sucrose from the growth medium led to an increase in the scientific yield. Alterations to the experimental procedures also resulted in increased seed germination and more vigorous growth of the plants in space. Altered storage and transfer procedures, including the use of GLACIER freezer during transport, maintained the low temperature requirements to obtain good quality RNA. Direct downlinking of digital images, eliminating video tapes, provided better quality images and simplified data analysis (Kiss et al. 2011).

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Related Web Sites

NASA to Study Plants to Help Astronauts Grow Food in Space

The Arabidopsis Information Resource

Miami University, Department of Botany

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Publications

• Millar K DL,Kumar P ,Correll M J,Mullen J L,Hangarter R P,Edelmann R E,Kizz J Z,A novel phototropic response to red light is revealed in microgravity New Phytologist 2010 186 648-656
• Kiss J Z,Kumar P ,Millar K DL,Edelmann R E,Correll M J,Operations of a spaceflight experiment to investigate plant tropisms Advances in Space Research 2009 44 879-886
• Perez-Nunez D ,Braby L A,Improvements in the re-flight of spaceflight experiments on plant tropisms Advances in Space Research 2011 47 545-552

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Ground Based Results Publications

• Correll M J,Edelmann R E,Hangarter R P,Mullen J L,Kiss J Z,Ground-based studies of tropisms in hardware developed for the European Modular Cultivation System (EMCS) Advances in Space Research 2005 36 1203-1210

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ISS Patent Publications

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Related Publications

• Correll M J,Kiss J Z,The roles of phytochromes in elongation and gravitropism of roots Plant and Cell Physiology 2005 46 317-323
• Mullen J L,Wolverton C ,Hangarter R ,Apical control, gravitropic signaling, and the growth of lateral roots in Arabidopsis Advances in Space Research 2005 36 1211-1217
• Molas M L,Kiss J Z,Correll M J,Gene profiling of the red light signalling pathways in roots Journal of Experimental Botany 2006 57 3217-3229
• Kiss J Z,Kumar P ,Bowman R N,Steele M K,Eodice M T,Correll M J,Edelmann R E,Biocompatibility studies in preparation for a spaceflight experiment on plant tropisms (TROPI) Advances in Space Research 2007 39 1154-1160
• Kumar P ,Montgomery C E,Kiss J Z,The role of pytochrome C in gravitropism and phototropism in Arabidopsis thaliana Functional Plant Biology 2008 35 298-305
• Matia I ,Gonzalez-Camacho F ,Herraanx R ,Kiss J Z,Gasset G ,van Loon J ,Marco R ,Medina F J,Plant cell proliferation and growth are altered by microgravity conditions in spaceflight Journal of Plant Physiology 2009 167 184-193

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Images

EMCS sample cartridge that will be spun in the EMCS centrifuge. Inset image is of Arabidopsis thaliana (thale cress) seedlings like the ones that will be used for Tropi. Tropi will compare the growth of root tips toward light in the absence of gravity, and allow the distinction between two redundant internal plant growth systems that respond to different colors of light. Image courtesy of NASA, Johnson Space Center.

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Screenshot of Tropi during Expedition 14 shows several cassettes in an Experiment Containers (EC) and the growth of young Arabidopsis thaliana seedlings during the "growth phase". Image courtesy of NASA, Johnson Space Center.

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Screenshot of Tropi at the beginning of "stimulation phase". This image will be used in analysis of tropisms. Image courtesy of NASA, Johnson Space Center.

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Principle Investigator John Kiss, Ph.D., from Miami University, Oxford, OH, and Ann-Iren Kittang from the Norwegian University of Science and Technology, Trondheim Norway, sit at the control console at N-USOC (Norwegian User Support and Operations Centre) in Trondheim, Norway during the second run of the Tropi investigation.

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NASA Image: ISS014E10652 - View of the TROPI seedling cassette for the European Modular Cultivation System (EMCS) - Experiment Container (EC) in the Destiny laboratory module during Expedition 14.

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RNA gels of frozen plant samples from the Tropi investigation. Gel A shows samples returned in Decmeber 2006 did not yield any RNA. Gel B shows RNA in the samples returned in June 2007 following the establishment of cold transfer procedures. Image courtesy of Dr. John Kiss.

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Close-up of Arabidopsis seedlings with seed cassette cover removed. Image courtesy of Ames Research Center, Moffett Field, CA.

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NASA Image: ISS022E087465 - NASA astronaut Jeffrey Williams, Expedition 22 commander, services the Tropism in Plants (TROPI2) experiment in the Columbus laboratory of the International Space Station.

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Dwarf Arabidopsis plant (left). Dwarf Arabidopsis plant (right). Image courtesy of Ames Research Center, Moffett Field, CA.

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European Modular Cultivation System (EMCS) Tropi experiment unique equipment (EUE) shown stimulating Arabidopsis seedlings with blue light (left). ENCS Tropi EUE shown stimulating Arabidopsis seedlings with red light (right). Image courtesy of Ames Research Center, Moffett Field, CA.

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