Biological Research in Canisters-19 (BRIC-19) - 07.29.15
Plants and animals grow in response to several environmental signals, from gravity to wind, but these signals don't exist in space, and that changes the way organisms grow and develop. The Biological Research in Canisters-19 (BRIC-19) investigation studies changes in gene activity, growth, and development of Arabidopsis thaliana (thale cress) seedlings germinated in space, comparing them to plants grown on Earth. The results address the roles of physical stresses, like gravity, and how genetic engineering might be used to produce plants that can thrive in the unique environment of microgravity. Science Results for Everyone
Information Pending Experiment Details
Simon Gilroy, Dr., University of Wisconsin, Madison, WI, United States
Sarah Swanson, University of Wisconsin-Madison, Madison, WY, United States
NASA Kennedy Space Center, Cape Canaveral, FL, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
September 2014 - March 2015
Previous ISS Missions
BRIC Series hardware has previously flown on STS-87, STS-107, STS-131, STS-135, SpaceX-2, and SpaceX-3.
The growth and development of animals and plants are both affected by the mechanical forces generated from their own weight. In the weightless environment of space, these mechanical signals are lost, and consequently growth and development are altered. To address how this loss of mechanical loading affects plants, seedlings of Arabidopsis thaliana (Mouse-ear cress) are grown aboard the international Space Station (ISS). Comparison of their patterns of growth and gene expression to ground-based controls is conducted to ask how the well-defined “fingerprints” of mechanical response, related to growth and gene expression, are altered in space. In addition, the investigation team characterizes the plants grown in space, whose mechanical signaling is artificially activated or inhibited by mutations in a gene, (TCH2,) that has been closely linked to mechanical signaling in this plant. The results of this investigation address the fundamental question of the role of mechanical loading in plant growth and development on Earth, and probes how the genetic engineering of genes related to mechanical signaling might be used to tailor plant growth to thrive in the unique environment of spaceflight.
Plant development is closely linked to mechanical forces either from the environment (e.g. wind) or generated internally from forces related to growth. Additionally, the weight of the plant itself acts to generate forces that control growth and development. The goal of the BRIC-19 experiment is to understand how the responses of plants are altered by growth in the microgravity environment of the ISS, where such signals are reduced.
This experiment analyzes these mechanically-related responses in Mouse-ear Cress (Arabidopsis), and in two mutants of this plant where a gene already known to be related to mechanical signaling (named 'touch 2', TCH2) is continuously activated or inactivated. These plants are germinated and grown as seedlings onboard the ISS, chemically fixed, and then frozen. The frozen samples are to be returned to earth for analysis of growth and patterns of gene expression.
Prior to launch, the seeds are planted under sterile conditions onto nutrient gel media, and then inserted into Petri Dish Fixation Units (PDFUs) that are, in turn, integrated into the Biological Research in Canister (BRIC) hardware. Five PDFUs will be used per BRIC, and two BRICs are dedicated to this experiment. To prevent germination of the planted seeds until reaching orbit, the BRICs are stored at 4˚C, and transported to the ISS in cold bags aboard SpaceX 4. Once on orbit, the BRIC canisters are allowed to warm to ambient, allowing for seed germination and growth. After 8 days, the seedlings are chemically fixed by injecting RNAlater fixative, utilizing the inbuilt injection capabilities of the BRIC-PDFU hardware. The samples are then frozen in the Minus Eighty-degree Laboratory Freezer for ISS (MELFI), and the frozen samples returned to earth for analysis of:
- Patterns of gene expression using the technique of RNA sequencing (RNAseq) to monitor the levels of expression of all genes in the plants (normal and the two mutant lines).
- Patterns of growth derived from images of the seedlings coupled to computer-based image analysis techniques to measure root and shoot growth.
These responses are compared between the normal plants and the mutants, where TCH2 is permanently activated, or inactivated, in both the spaceflight samples and parallel controls grown on the ground under identical conditions. This set of comparisons should help define how loss of mechanical signals affects growth and development in spaceflight, and whether manipulating the mechanical signaling system through making defined mutants in mechanical signaling elements can alter or reverse these effects. The results from this analysis can help define how plants respond to their own weight on Earth, and also how removing the stimulus of weight affects plant growth and development on orbit. ^ back to top
Future long-duration space missions, including those to an asteroid, or outposts on the moon or Mars, may require space travelers to grow their own food. Understanding the genetic changes that happen to plants grown in microgravity can help researchers develop plants that can thrive as space crops. The BRIC-Petri Dish Fixation Unit is used to germinate and grow seedlings, as well as deliver a chemical that stops growth and preserves the seedlings so they can be compared with plants grown on Earth.
Most plants evolved to grow up from the ground, despite gravity acting on their own weight and pulling them down. Understanding the genetic responses to cues like gravity, sheds new light on basic plant growth phenomena. A greater understanding of plant physiology has implications for improving agricultural and biomass production, benefiting people on Earth.
BRIC-19 is a sortie flight and samples are returned on the same flight and have the following operational requirements:
• Late stow at L-24 hours in a double cold bag.
• Actuation performed by the crew at 8 days after cold bag unpack.
• Samples are frozen in the Minus Eighty-degree Laboratory Freezer for ISS (MELFI).
The BRIC-19 payload is stowed in a double cold bag for ascent to ISS on a SpaceX Dragon Spacecraft. At 8 days after cold bag unpacking, the payload hardware is accessed for activation. A rod is removed from the Rod Kit and inserted into the BRIC-PDFU Actuator Tool. The BRIC-PDFU Actuator Tool is then attached to the selected BRIC-PDFU canister lid in position 1, and is used to mechanically force RNAlater fixative into the Petri dishes. The process is repeated until all the PDFUs are activated in all four canisters. After a 12 hour stabilization period, the canisters are transferred to the MELFI for freezing of the samples at -80°C or less.
Information Pending^ back to top
Ground Based Results Publications
Toyota M, Gilroy S. Gravitropism and mechanical signaling in plants. American Journal of Botany. 2013 January; 100(1): 111-125. DOI: 10.3732/ajb.1200408. PMID: 23281392.
Toyota M, Ikeda N, Sawai-Toyota S, Kato T, Gilroy S, Tasaka M, Morita MT. Amyloplast displacement is necessary for gravisensing in Arabidopsis shoots as revealed by a centrifuge microscope. The Plant Journal. 2013 nOVEMBER; 76(4): 648-660. DOI: 10.1111/tpj.12324. PMID: 24004104.
Jayaraman D, Gilroy S, Ane J. Staying in touch: mechanical signals in plant-microbe interactions . Current Opinion in Plant Biology. 2014 May 26; 20c: 104-109. DOI: 10.1016/j.pbi.2014.05.003. PMID: 24875767.
Plants in Microgravity
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