Biological Research In Canisters -16: Actin Regulation of Arabidopsis Root Growth and Orientation During Space Flight (BRIC-16-Regulation) - 08.10.16
Biological Research In Canisters - 16: Actin Regulation of Arabidopsis Root Growth and Orientation During Space Flight (BRIC-16-Regulation) studies how actin cytoskeleton dictates root growth orientation during space flight and conducts an extensive set of genome-wide microarray studies to unravel actin-dependent gene regulatory networks that modulate root growth and orientation during space flight. Science Results for Everyone
This research gets to the root of the problem. Microgravity caused changes in the expression of plant genes that are essential for normal growth of root hairs. Root hairs are single cells located on the root surface. On Earth, root hairs help roots absorb nutrients more efficiently. Space also causes roots to skew to one side and even coil up. These changes in the patterns of root growth are indicative of changes in the protein filaments and carbohydrate-rich cell wall that support cell structure. Extensive growth of vacuoles, or storage sacs, seen on roots in space could affect gravity sensing and growth direction as well. Using microgravity simulation devices, scientists hope to continue studying gravity’s role in growth of food plants for space exploration and advancing agriculture on Earth. Experiment Details
Elison Blancaflor, Ph.D., Samuel Roberts Noble Foundation Incorporated, Ardmore, OK, United States
Yuhong Tang, Samuel Roberts Noble Foundation Incorporated, Ardmore, OK, United States
Jin Nakashima, Ph.D., Samuel Roberts Noble Foundation Incorporated, Ardmore, OK, United States
Bionetics Corporation, Cape Canaveral, FL, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
March 2010 - September 2010
ISS Expedition 23/24 is the first mission for BRIC-16-Regulation.
- BRIC-16-Regulation focuses on Arabidopsis, the preferred model species for plant investigations in space. Arabidopsis is a small plant with a short generation time and the advantages of a small genome size, a wealth of available genetic mutants, and an already well characterized pattern of development.
- BRIC-16 flies Arabidopsis seeds on a Space Shuttle mission during which the seeds will germinate grow, and are subsequently returned to Earth when the Space Shuttle lands. Crewmembers will perform an inflight chemical fixation to preserve the seedlings on-orbit prior to return.
- These investigations will study how plants perceive and respond to gravity, and how gene regulation is altered by space flight conditions. The fundamental knowledge gained through these investigations will aid in our ability to better control plant use on Earth in agriculture (and other) applications.
Providing a continuous supply of food, oxygen, and clean water for humans in space is a costly proposition. To date these needs have been met largely through stowage and resupply. As the durations of missions increase, the costs associated with this approach become prohibitive. For this reason, virtually all scenarios for long-term space missions involve plants as key components of the life support environment. Plants will be used to recycle wastes, remove carbon dioxide, purify water and produce oxygen and food for astronauts Biological Research In Canisters - 16: Actin Regulation of Arabidopsis Root Growth and Orientation During Space Flight (BRIC-16-Regulation) examines how the actin cytoskeleton dictates root growth orientation during space flight. The guiding hypothesis is that actin filaments (F-actin) negatively regulate environmental and endogenous signals to specify root orientation on Earth and in space. This hypothesis is based on previous ground based research demonstrating that F-actin disruption enhances the sensitivity of roots to gravity. Arabidopsis seedlings with a transfer (T)- DNA mutation in a vegetative actin isoform (act2) and the short-duration microgravity environment provided by a Space Shuttle mission are used to test the hypothesis. Microgravity is an essential component of the experiment since it will help determine the impact of other signals on root orientation that are typically masked by the strong gravitational force on Earth. Root orientation and amyloplast position of dark-grown act2 and wild-type seedlings are quantified. In parallel, an extensive set of genome-wide microarray studies using gene arrays to unravel actin-dependent gene regulatory networks that modulate root growth and orientation during space flight are conducted. We expect to collect data that will pave the way for an in depth understanding of plant growth under microgravity conditions.
The fundamental knowledge gained by growing plants under microgravity conditions can contribute to resolving the following risks:
- Providing and Maintaing Biodegenerative Life Support Systems
- Maintaining Food Quantity and Quality
- Maintaining Acceptable Atmosphere
- Managing Waste
- Providing and Recovering Potable Water
The microgravity of space will be used to investigate and clarify plant-related phenomena that cannot be studied in the presence of gravity. The fundamental knowledge gained through these investigations will aid in our understanding of basic plant processes that can eventually increase our ability to better control plant use on Earth in agriculture (and other) applications.
Operational Requirements and Protocols
This is a passive payload, with no on-orbit power or communications available. The investigators will plate their biology onto 60 mm petri dishes containing agar-solidified media. Each petri dish will be placed inside its own Petri Dish Fixation Unit (PDFU). The PDFUs will be assembled and loaded with a fixative in the fluid compartment. Five PDFUs plus one temperature data logger will be loaded into each BRIC-PDFU (Biological Research In Canisters - Petri Dish Fixation Unit). Preflight turnover will be 26 hours prior to launch. In the event of a launch scrub, the entire assembly will be replaced with an identical back-up unit with freshly loaded biology. Crewmembers will perform one in-flight operation per petri dish (using actuator equipment) to chemically fix the tissues on-orbit prior to return (using Glutaraldehyde and RNAlater). The PDFUs will remain contained within the BRIC-PDFUs during all phases of flight operations. The fixed samples will be subsequently returned to Earth for postflight processing..
Eight BRIC-PDFU canisters reside in ½ middeck locker drawer. During Actuation operations, the drawer is removed, and the BRIC canisters removed one at a time. The Actuator Tool and Rod Kit are removed from another middeck locker location. A single rod from the rod kit is inserted into the Actuator Tool. The Actuator Tool is used to insert the rod into a single location on a BRIC canister lid. Squeezing the handle on the Actuator Tool forces the rod through septa on the BRIC canister lid, then through septa on one of the PDFUs inside the canister. The rod forces a piston inside the PDFU to move fixatives from a storage volume into the Petri dish volume inside the PDFU. After Actuation, the rod remains contained inside the BRIC canister. The crew do not come in contact with fixatives, which remain contained within 3 levels of containment throughout all phases of flight. The Actutation is repeated for all 5 PDFU locations within each of the eight BRICs, totaling 40 PDFUs, and 40 Actutations. The Actuation procedure is performed in 30 minutes. For the remainder of flight, the BRIC operates autonomously with no crew interface.
Decadal Survey Recommendations
Plant and Microbial Biology P2
On the ground, plants know to instruct their major organs (i.e., roots and shoots) to grow away or toward the direction of gravity, a process referred to as gravitropism. Normally, roots grow downward into the soil to absorb water and nutrients while the shoots reach upward for light energy. Plants will be an important part of advanced life support systems, and they can also serve as a food source during long space exploration missions so understanding how space travel affects plant growth is crucial. Seedlings of Arabidopsis thaliana - a small flowering plant related to mustard and cabbage , and extensively used in plant research - were grown in the Biological Research in Canisters (BRIC) hardware on board the space shuttle Discovery making a visit to the International Space Station (ISS). Scientists found that long-term exposure to microgravity negatively impacts the growth of tiny hair cells on the root surface, which are important for water and nutrient uptake. The reduced growth of root hairs was accompanied by changes in the expression of genes essential for normal plant cell development. This effect has profound implications for plant adaptation to microgravity as new plant varieties to support long space missions will have to be developed so they can minimize the adverse effects of microgravity on a cell type that is crucial for efficient nutrient capture. Space roots also exhibited a tendency to skew to one side, resulting in root coiling in some instances. This suggests that the actin cytoskeleton (protein filaments that provide structural support for cells) might be involved in gravity sensing and touch signaling both in space and on Earth, and that the enhanced root skewing could be a manifestation of suppressed genes essential for the function of actin. In addition, it was found that spaceflight led to the extensive formation of vacuoles, or storage sacs, in roots, which could also affect gravity sensing and root growth direction. Given these observations, scientists expect that simulated microgravity devices could serve as an excellent experimental tool for follow-up studies of certain aspects of root growth in space. It is important to note that basic understanding of root gravitropism is highly relevant to agricultural sustainability on Earth because of the potential for using such information to create new crop varieties that are more efficient in exploring the soil for water and nutrients.^ back to top
Nakashima J, Liao F, Sparks JA, Tang Y, Blancaflor E. The actin cytoskeleton is a suppressor of the endogenous skewing behaviour of Arabidopsis primary roots in microgravity. Plant Biology. 2013 August; 16: 142-150. DOI: 10.1111/plb.12062. PMID: 23952736.
Kwon T, Sparks JA, Nakashima J, Allen SN, Tang Y, Blancaflor E. Transcriptional response of Arabidopsis seedlings during spaceflight reveals peroxidase and cell wall remodeling genes associated with root hair development. American Journal of Botany. 2015 January 1; 102(1): 21-35. DOI: 10.3732/ajb.1400458. PMID: 25587145.
Ground Based Results Publications
Blancaflor E. Regulation of plant gravity sensing and signaling by the actin cytoskeleton. American Journal of Botany. 2012 September 21; 100(1): 143-152. DOI: 10.3732/ajb.1200283. PMID: 23002165.
Dyachok J, Sparks JA, Liao F, Wang Y, Blancaflor E. Fluorescent protein-based reporters of the actin cytoskeleton in living plant cells: fluorophore variant, actin binding domain, and promoter considerations. Cytoskeleton . 2014 May; 71(5): 311-327. DOI: 10.1002/cm.21174. PMID: 24659536.
Ground studies show that roots of knock-outs to the vegetative ACT2 gene display stronger curvature responses when provided with a 30 min horizontal gravistimulation followed by rotation for 5 h on a 2-D clinostat (courtesy of E. Blancaflor)
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A. View of a PDFU on its side (launch position). B. Five PDFUs plus one temperature logger within a BRIC-PDFU canister prior to closure. C. BRIC-PDFU canister with two pin guards attached. D. Eight BRIC-PDFU canisters stowed within a half middeck locker (as flown on STS-131).
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Injection of fluids into PDFU petri dishes. A. Actuator Rod Kit and Actuator Tool. B. Actuator Tool attached to BRIC-PDFU canister after using the Actuator to push fluid into the PDFU.
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NASA Image: JSC2010E057530 - Image of Biological Research In Canisters (BRIC)-16 middeck payload hardware.
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NASA Image: S135E012237 - Astronaut Rex Walheim works with the Biological Research in Canisters experiment.
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NASA Image: S135E012252 - Astronaut Rex Walheim poses for a photo with Biological Research in Canisters experiment.
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