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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