ASGSB 2003 Annual Meeting Abstracts


GENE EXPRESSION OF THE RD29/GFP BIOSENSOR AND SEVERAL NATIVE GENES IN TRANSGENIC ARABIDOPSIS THALIANA SUBJECTED TO ABIOTIC STRESS.  B.P. Hubbard1, A-L. Paul2, R.J. Ferl2 1University of Ottawa, ON, Canada, and 2Department of Horticultural Sciences, University of Florida, Gainseville.

   Transgenic Arabidopsis thaliana containing the Response to Desiccation 29/Green Fluorescent Protein (RD29/GFP) transgene were used in experiments that evaluated the differential expression of several native genes associated with desiccation, cold, and hypoxic stresses. In addition, expression of the RD29/GFP biosensor was used to visually monitor the desiccation response. Pre-flight experiments characterized the gene expression of RD29, Low Temperature Induced 30 (LTI30/Xero2), Alcohol dehydrogenase (Adh), and Pyruvate decarboxylase (Pdc) in response to controlled stress inductions on the plants. RD29/GFP Arabidopsis plants were exposed to either cold temperatures (4oC), hypoxia simulated by flooding, or atmospheric desiccation. Hypoxia and desiccation experiments were recapitulated in the Plant Growth Facility (PGF) during a simulated spaceflight mission (LASSE) launched in the Orbiter Environmental Simulator (OES). These experiments sought to explore the possibility of synergistically altered expression of RD29, Xero2, and Late Embryogenesis Abundant (LEA) caused by the environmental conditions of the PGF. Plant Growth Chamber A (PGC-A) experienced the ambient conditions of the OES which were designed to mimic those of a space orbiter cabin, while the conditions in PGC-B were adjusted to pre-set limits for CO2 and scrubbed for Volatile Organic Compounds (VOCs). In both experiments, gene characterization was performed using fluorescent imaging and RT-PCR. The results of the ground experiments indicate that after 44 hours of exposure, RD29 and Xero2 are induced in plants subjected to desiccation. The results of the flight experiment demonstrate that cabin conditions may contribute to changes in RD29, Xero2, and LEA expression, relative to controls. These results lead to the hypothesis that elevated levels of CO2 and other VOCs may influence gene expression in spaceflight experiments.

(Supported by NASA’s 2003 Spaceflight and Life Sciences Training Program and the Canadian Space Agency)


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