Poster: Oxidative Stress
Abs #
129: The function and sub-cellular localization of APX3 in Arabidopsis thaliana
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Presenter: |
Narendra, Savitha , snarendr@ttacs.ttu.edu | Authors | Narendra, Savitha (A) Wang, Jing (A) Yan, Juqiang (A) Mano, Shoji (B) Nishimura, Mikio (B) Zhang, Hong (A) | | Affiliations: |
(A): Texas Tech University, Lubbock, TX
(B): National Institute for Basic Biology, Okazaki, Japan
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The physiological condition associated with increased production of reactive oxygen species (ROS, e.g.: O2-, H2O2, .OH) is called oxidative stress. Enzymatic actions of superoxide dismutase, catalase and ascorbate peroxidase (APX) remove ROS in plant cells. APXs are H202-scavenging enzymes that protect plant cells from the toxic effects of H202. However, it is not necessarily advantageous for the plant to remove all H202 as soon as it is produced because it plays an important role in cell wall cross-linking, plant defense and cell signaling. We previously found that a 14-3-3-interacting ascorbate peroxidase, APX3, is likely to be peroxisomal membrane-bound. To test this hypothesis, we used GFP-APX3 and APX3-GFP fusion proteins to determine where APX3 was localized. Data from studying GFP-APX3 overexpression plants indicate that APX3 is indeed localized to peroxisomes, which was confirmed by using GFP-PTS1 transgenic plants as a positive control (PTS1 is the peroxisomal targeting signal 1). As a negative control, the free GFP expressed in plant cells is normally found in cytoplasm, indicating that GFP does not interfere with the correct localization of APX3 when it is fused to APX3. To study the in vivo function of APX3, we are currently analyzing APX3 knockout plants and anti-APX3 transgenic plants. Preliminary data indicate that an increased transcript level of the PR-1 gene is found in both antisense plants and GFP-APX3 overexpression plants. Furthermore, the APX3-GFP transgenic plants were significantly more tolerant to heat stress as compared to the wild type control plants. Most recent data from on going studies will be reported at the meeting.
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