Seedling Growth-2 (Seedling Growth-2) - 03.04.14
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Seedling Growth-2 Research Objectives: Seedling Growth-2 is the second part of the Seedling Growth Experiment series and uses the plant Arabidopsis thaliana to determine the effects of gravity on cellular signaling mechanisms of phototropism and to investigate cell growth and proliferation responses to light stimulation in microgravity conditions. The investigation will determine, (1) Is the red light effect on blue-light-based phototropism a direct or indirect effect?; (2) What are the alterations in red-light-based phototropism of plants defective in essential components of auxin transport or lacking essential factors of cell growth and proliferation?; (3) What are the effects of a red light photostimulation on cell growth and proliferation under conditions of gravitational stress? Seedling Growth 2 requires three EMCS runs to be performed to collect image data and frozen samples.
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OpNom Seedling Growth-X
NASA Ames Research Center, Moffett Field, CA, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
March 2014 - September 2014
Previous ISS Missions
TROPI-2; TROPI2; GENARA-A; Seedling Growth-1
- This project aims to determine the combined effects of gravity and light on cellular signaling mechanisms of phototropism and to know the cellular response to light stimulation in microgravity conditions, regarding cell growth and proliferation. Improved knowledge of these basic mechanistic processes is vital to use plants in bioregenerative life support system, in explortion initiative to the Moon and Mars.
- First, we will determine the effects and influence of gravity on light responses, to better understand cellular signaling mechanisms of phototropism. Second, we will investigate the relationship betweenlight and gravity by measuring the shoots in fractional gravity. Third, we will determine the cellular response to light stimulation under environmental conditions of microgravity or fractional gravity in space. Fourth, we will focused on root cell growth and proliferation, two basic and essential cell processes which are fundamental for the plant developmental program.
- This project is an international collaborative effort among scientists in Spain, France, and the USA. From a scientific perspective, the project intends to establish a relationship between two biological processes already investigated in microgravity, namely light stimulation and cell proliferation, including the role played by the key plant hormone auxin.
This experiment builds on previous spaceflight experiments for both Principal Investigators (Dr. John Z. Kiss and Dr. F. Javier Medina) using the model plant Arabidopsis thaliana to study the combined effects of light and gravity on plant growth, development and proliferation.
The experiment is a collaboration between a NASA PI (Kiss) and an ESA PI (Medina) and is co-sponsored by NASA and ESA.
In previous experiments by the PIs in the EMCS on the ISS, data were obtained on the phytochrome photoreceptors responsible for the phototropic response of seedlings grown in microgravity. Growth, development, and phototropic curvature of plants in response to varying qualities of light were analyzed, as well as global gene expression changes using DNA microarrays.
In the ROOT experiment (Medina, ISS) and in the experiments GENARA and ROOT CELL PROLIFERATION (approached until now in ground-based facilities), results indicated that cell growth and proliferation in root meristems were altered by changing the effective gravity, including the expression of relevant cell cycle genes. Furthermore, the distribution of auxin was altered, resulting in modifications of the pattern of primary and secondary root growth.
Since previous research has already shown the perception phase of phototropism, this experiment focuses on the signal transduction phase and on the crosstalk between the red and blue light signaling pathways, by means of the use of different mutants in the transduction pathways. The contribution of light stimuli to the regulation of cell growth and proliferation will be evaluated by using morphometry and immunolocalization methods on the indicated mutants and using red-light treatments to auxin mutants, to ribosome biogenesis mutants as well as to transformed lines containing the GFP reporter gene coupled with auxin-responsive elements and with regulators of cell cycle and ribosome biogenesis. On these materials, microscopical and RT-PCR postflight analyses will be performed.
Since down mass is limited in the spaceflight opportunities, a part of these experiments will be accomplished with telescience and, during experimental runs, images of seedlings will be downlinked to Earth.
Significant to the success of this proposal is that the PI teams are already experienced with the European Modular Cultivation System (EMCS). The US group was the first group to successfully use this research facility on the ISS in a project termed as outlined in our recent publications (Kiss et al. 2011; Millar et al. 2010). The European groups have used the EMCS in the GENARA experiment. In addition, the PIs have done extensive ground-based testing at NASA facilities and have performed tests in Europe on the engineering and flight models.
In terms of long-term research goals, the flowering plant Arabidopsis is an excellent model for spaceflight experiments because of its small size and simple growth requirements. A number of US and international agencies have supported Arabidopsis research efforts, including the establishment major genome programs. Indeed, Arabidopsis has already proven to be a valuable experimental model during several spaceflight experiments by our group and others. Again, since the EMCS has a variable speed centrifuge, this project is also relevant to the emphasis to understand how plant growth and development occurs at fractional g-levels, such as those found on the Moon and Mars.
The major goals of this project are to determine how gravity and light responses influence each other in plants and to better understand the cellular signaling mechanisms involved in plant tropisms. This proposed project builds on previous spaceflight experiments on the ISS with the EMCS using the model plant Arabidopsis. This new experiment is designed to confirm and extend previous data from the recent ISS experiment of a novel red-light-based positive phototropic response in plant shoots. The hypothesis is that positive red-light-sensing, which was known in older plant lineages, is masked by normal 1-g conditions in more recently evolved lineages. The experiment also investigates fundamental interactions among red and blue light signaling pathways and the gravity sensing mechanisms. The ISS is the only laboratory facility where it is possible to reliably and simultaneously vary light and gravity stimuli for the proposed experiments. A significant advantage of this proposed project is the use of existing flight hardware that has been flown successfully and allowed for growth of Arabidopsis seedlings in the EMCS. This project is also relevant to the recent emphasis at NASA to study plant growth and development at fractional g-levels such as those found on the moon and Mars. Improved knowledge of the basic mechanistic processes that will be the focus of this project is vital to develop ways to use plants in extraterrestrial bioregenerative life support systems.
The proposed research is relevant to understanding plant requirements in space. Arabidopsis is an excellent model plant for spaceflight experiments because of its small size and simple growth requirements. A number of US and international agencies have supported Arabidopsis research efforts, including the establishment of major genome programs. Indeed, Arabidopsis has already proven to be a valuable experimental model during several spaceflight experiments by the PIs and others, and is one of the model systems targeted for research by NASA. Since the EMCS has a variable speed centrifuge, this project is also relevant to the emphasis at NASA to understand how plant growth and development occurs at fractional gravity levels, such as those found on the Moon and Mars. This project deals with light and gravity sensing, which are both key parameters for the growth and development of plants. Thus, understanding these factors will help to develop strategies to optimize light sensing, and, in turn, to better modify plant species by using biotechnological approaches to improve crop plants. In addition, from this type of research, improvements in agricultural biotechnology can be realized and can contribute to goals of increased production, lessened environmental impact, and sustainability of agricultural production. Therefore, in the long-term, the research also is relevant to improving the characteristics of crop plants to benefit human agriculture on Earth.
- Deliver ECs/EUE/Seed Cassettes to ISS.
- For launch, ECs should be oriented such that launch loads are directed perpendicular to the base plate.
- At TBD times, images will be automatically down linked.
- Functional EMCS is required to conduct experiment runs.
- Frozen storage of Seed Cassettes, ambient stowage of ECs return to Earth.
- Once frozen, samples must not be exposed to ambient air temperature for longer than 3 minutes at any time.
- 1. Crew install ECs into EMCS Facility for run #1.
- 2. Experiment initiated by crew and by ground command from NUSOC, Norway.
- 3. At conclusion of run # 1, crew remove ECs from EMCS.
- 4. Crew remove Seed Cassettes, place Seed Cassettes in EMCS Cold Storage Bags, and freeze in MELFI.
- 5. Crew install ECs in EMCS and repeat the experiment as run #2 with new ECs.
- 6. At the end of run #2, crew remove the ECs from the EMCS, remove Seed Cassettes, place Seed Cassettes in EMCS Cold Storage Bags, and freeze in MELFI.
- 7. Crew install 8 ECS in EMCS and conduct the experiment as run #3.
- 8. At conclusion of run # 3, crew remove 8 ECs from EMCS.
- 9. Crew remove Seed Cassettes, place Seed Cassettes in EMCS Cold Storage Bags, and freeze in MELFI.
- 10.Crew place ECs in ambient stowage until return to Earth.
- 11. For return to Earth, place all frozen Seed Cassettes in GLACIER
Ground Based Results Publications
Kiss JZ, Kiss JZ, Kumar P, Millar KD, Millar KD, Edelmann RE, Correll MJ. Operations of a spaceflight experiment to investigate plant tropisms. Advances in Space Research. 2009; 44(8): 879-886.
Matia I, Gonzalez-Camacho F, Herranz R, Kiss JZ, Kiss JZ, Gasset G, van Loon JJ, van Loon JJ, Marco R, Medina F. Plant Cell Proliferation and Growth Are Altered by Microgravity Conditions in Spaceflight. Journal of Plant Physiology. 2010; 167(3): 184-193. DOI: 10.1016/j.jplph.2009.08.012. PMID: 19864040.
Millar KD, Millar KD, Kumar P, Correll MJ, Mullen JL, Hangarter RP, Edelmann RE, Kiss JZ, Kiss JZ. A novel phototropic response to red light is revealed in microgravity. New Phytologist. 2010; 186(3): 648-656. DOI: 10.1111/j.1469-8137.2010.03211.x.
Kiss JZ, Kiss JZ, Millar KD, Millar KD, Edelmann RE. Phototropism of Arabidopsis thaliana in microgravity and fractional gravity on the International Space Station. Planta. 2012; 236(2): 635-645. DOI: 10.1007/s00425-012-1633-y. PMID: 22481136.
Kiss JZ, Kiss JZ, Millar KD, Millar KD, Kumar P, Edelmann RE, Correll MJ. Improvements in the re-flight of spaceflight experiments on plant tropisms. Advances in Space Research. 2011; 47(3): 545-552. DOI: 10.1016/j.asr.2010.09.024.
Space Biosciences Division
Department of Botany/John Kiss
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