Gravity Related Genes in Arabidopsis - A (Genara-A) - 08.20.14
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Gravity Related Genes in Arabidopsis - A (Genara-A) seeks to provide an understanding of microgravity induced altered molecular activities which will help to find plant systems that compensate the negative impact on plant growth in space.
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Plants get stressed out in space. This investigation of how microgravity alters molecular activities in plants helps identify those plants which can compensate for the negative effect of space on growth. Membrane proteins were extracted from seedlings grown in space, on a 1-G reference centrifuge, and on the ground. Among 1,484 proteins identified and quantified, 80 were significantly more abundant in the seedlings grown in microgravity in space. Proteins associated with metabolism and movement of growth hormones were depleted by microgravity, while those associated with stress responses, defense, and metabolism were more abundant. This indicates that plants perceive microgravity as a stressful environment.
EADS Astrium, Friedrichshafen, , Germany
Sponsoring Space Agency
European Space Agency (ESA)
ISS Expedition Duration
March 2010 - March 2011
Previous ISS Missions
Genara-A is scheduled for its first operations on ISS Increment 23/24.
- Gravity Related Genes in Arabidopsis - A (Genara-A) will address the existence of gravity regulated genes, which affect the mechanism of gravisensing and the redistribution of plant growth hormones.
- For this purpose the growth of Arabidopsis shall be followed by optical observation of 1g reference samples and samples grown under microgravity.
- Genara-A will provide an understanding of microgravity induced altered molecular activities which will help to find plant systems that compensate the negative impact on plant growth in space, an aspect of special importance for the application of plant based systems in life support systems or as food source for long-duration space flights beyond low Earth orbit.
The existence of gravity regulated genes, whose expression depends (at least) upon the mechanism of gravisensing and the redistribution of hormones, shall be addressed properly in this experiment. In transgenic Arabidopsis plants, several biomonitors will report the distribution of IAA (plant hormone auxin [Indole-3-Acetic Acid]) and ABA (plant hormone [Abscisic Acid]) at the tissue level in microgravity or in the 1-g centrifuge.
Arabidopsis thalianaseedlings are launched dry state inside cultivation chambers (CCs). An impregnated filter paper below the seeds contains required nutrients for germination and growth, so that germination can be started by hydration with distilled water. A total of ninety-six CCs are flown.
For processing, the samples are provided with artificial air with a composition of oxygen, nitrogen, carbon dioxide and water according to the investigator specifications at a temperature of 22 degrees Celsius. The growth of the Arabidopsis is observed and recorded by the European Modular Cultivation System (EMCS) provided video observation and recording subsystems.
Following processing the CCs are removed from the ECs and either frozen at a temperature of -80 degrees Celsius in MELFI, and returned to ground in this condition in a suitable cold storage or filled with GUS-Assay and incubated in a incubator at a temperature of 37 degrees Celsius for 12 hours, first, and only afterwards frozen at -80 degrees C in MELFI. Currently GUS treatment is planned for 16 CCs.
12-day-old seedlings were grown either in space, in the European Modular Cultivation System (EMCS) under microgravity or on a 1g reference centrifuge, or on the ground. Proteins associated with membranes were selectively extracted from microsomes and identified and quantified through LC-MS-MS using a label-free method, i.e. a method in mass spectrometry that aims to determine the relative amount of proteins in biological samples. Among the 1484 proteins identified and quantified in the 3 conditions mentioned above, 80 membrane-associated proteins were significantly more abundant in seedlings grown under microgravity in space than under 1g and 69 were less abundant. Clustering of these proteins according to their predicted function indicates that proteins associated with auxin metabolism and trafficking were depleted in the microsomal fraction in microgravity space conditions, whereas proteins associated with stress responses, defence and metabolism were more abundant in microgravity than under 1g indicating that microgravity is perceived by plants as a stressful environment. These results clearly indicate that a global membrane proteomics approach can give a snapshot of the cell status and its signaling activity at a given time in response to microgravity and highlight the major processes affected.
Manzano AI, Matia I, Gonzalez-Camacho F, Carnero-Diaz E, van Loon JJ, van Loon JJ, Dijkstra CE, Dijkstra CE, Larkin O, Anthony P, Davey MR, Marco R, Medina F. Germination of Arabidopsis Seed in Space and in Simulated Microgravity: Alterations in Root Cell Growth and Proliferation. Microgravity Science and Technology. 2009; 21(4): 293-297.
Carnero-Diaz E, Grat S, Eche B, Boucheron-Dubuisson E, Medina F, Pereda-Loth V, Rossignol M, Pichereaux C, Briere C, Graziana A, Mazars C. Global membrane-proteome changes induced by microgravity: preliminary results from the GENARA-A experiment performed on ISS. Satellite Workshop to the Plant Biology Congress, Freiburg, Germany; 2012 August 1-3
Mazars C, Briere C, Grat S, Pichereaux C, Rossignol M, Pereda-Loth V, Eche B, Boucheron-Dubuisson E, Le Disquet I, Medina F, Graziana A, Carnero-Diaz E. Microgravity induces changes in microsome-associated proteins of Arabidopsis seedlings grown on board the international space station. PLOS ONE. 2014 March 11; 9(3): e91814. DOI: 10.1371/journal.pone.0091814. PMID: 24618597.
Ground Based Results Publications
Valbuena MA, Manzano AI, van Loon JJ, van Loon JJ, Saez-Vasquez J, Carnero-Diaz E, Herranz R, Medina F. Auxin transport and ribosome biogenesis mutant/reporter lines to study plant cell growth and proliferation under altered gravity. The Joint Life Science Symposium, Aberdeen, United Kingdom; 2012 June 18-22 2 pp.
Herranz R, Medina F. Role of gene and pathways redundancy in plant and animal unique transcriptomic states under altered gravity. 2012 Life in Space for Life on Earth Symposium, Aberdeen, United Kingdom; 2012 June 18-22
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