ASGSB 2003 Annual Meeting Abstracts
THE EFFECTS OF A SIMULATED
FLIGHT ENVIRONMENT ON ADH/GFRP EXPRESSION IN ARABIDOPSIS THALIANA.
R.P. Ocampo1, A-L Paul2,
1Dept of Psychology, Haverford College,
Sciences Department, University of Florida.
Plants grown in space
have been shown to produce higher levels of alcohol dehydrogenase (ADH), a
protein closely associated with hypoxic stress. While low oxygen conditions
initiate this response on Earth, there is some uncertainty as to what factors
stimulate this response in space. High CO2,
elevated ethylene levels, and reduced air flowóconditions which are typically
found on board the space shuttle and International Space Stationómay
contribute. This experiment evaluated these parameters in an attempt to
understand how non-microgravity related factors impact Adh expression.
Arabidopsis plants containing the Adh/GFP transgene were used to compare
closed and open environmental conditions in the Plant Growth Facility (PGF).
Half of the plants in the PGF experienced elevated CO2 and
ethylene levels, while the remaining plants were controlled for gas
fluctuations. Both sets of plants were surveyed for differential gene
expression between treatments with Real Time PCR and compared to ground
controls. Plants were also observed with fluorescent imaging for qualitative
analysis of Adh/GFP transgene expression. Plants grown in the closed
environment, particularly those exposed to high ethylene concentrations,
expressed Adh at higher levels than those grown in an open environment. In
addition, two other genes associated with hypoxia, Pyruvate decarboxylase (Pdc)
and Arabidopsis non-symbiotic hemoglobin (Ahb) also showed significantly
higher expression in the closed environmental condition. These results
indicate that environmental factors related to spaceflight but unrelated to
microgravity contribute to the stress response in plants.
(Supported by NASA's 2003
Spaceflight and Life Sciences Training Program)
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