CENTENNIAL HONORS COLLEGE
Western Illinois University
Undergraduate Research Day 2015
Poster Presentation
The Effect of Elevated Levels of Ozone on the Accumulation of Lipids in a Mutant of
Arabidopsis thaliana That Is Defective In a Major Chloroplast Receptor
Gina Meier
Faculty Mentor: Meshack Afitlhile
Biology
Ground level ozone can have harmful effects on vegetation because it forms reactive oxygen species
(ROS) in the cell cytoplasm. The endogenous containment system of polyunsaturated fatty acids (PUFAs)
and ozone-induced proteins provide a buffering system to counteract ROS. However, if plants are unable
to effectively scavenge ROS, a gene that encodes ACC oxidase is stimulated, which leads to ethyleneinduced programmed cell death and necrotic tissue. Under these conditions, PUFAs break down to
produce malondialdehyde (MDA). Since MDA is formed in the stroma, this suggests that chloroplast
lipids enriched in PUFAs are a source of MDA. Our preliminary results show increased levels of MDA
and necrotic tissues after Arabidopsis thaliana has been exposed to ozone for 3h and left in ozone-free
environment for 21 hours. We hypothesize that elevated levels of ROS will stimulate chloroplast-tonuclear signaling, which may result in repression of genes that encode lipid synthesizing enzymes and
fatty acid desaturases.