Gillespie, Kelly M , Chae, June M , Leakey, Andrew D B , Ainsworth, Elizabeth A .
Integration of metabolite with transcript and enzyme activity profiles of the antioxidant system in soybeans when grown at elevated levels carbon dioxide and ozone.
Practically all adverse environmental conditions can disrupt the homeostasis of plant cells, enhance the production of reactive oxygen species, and increase antioxidant metabolism. While rising tropospheric ozone concentrations ([O3]) will likely increase oxidative stress, how the combination of rising carbon dioxide concentrations ([CO2]) and [O3] will alter plant antioxidant metabolism is unknown. Currently opposing hypotheses exist as to whether elevated [CO2] will ameliorate or intensify the damaging physiological effects of elevated [O3]. This research is investigating these opposing hypotheses at the Soybean Free Air Concentration Enrichment (SoyFACE) facility, where soybean (Glycine max Merr.) is grown under fully open air conditions at [CO2] and [O3] predicted for 2050. Leaves were sampled across the 2005 and 2006 growing seasons and at different stages of development. The response of antioxidant transcripts, enzymes and metabolites to rising [CO2] and [O3] are being investigated. In 2005 and 2006, total antioxidant capacity, measured as Trolox equivalents, of soybean leaves increased over the growing season, regardless of growth [CO2] or [O3]. Elevated [CO2] reduced total phenolic content in soybeans, while elevated [O3] increased phenolic content. Total ascorbate concentration increased across the growing season regardless of treatment. However, elevated [O3] decreased the redox potential of the ascorbate pool. Further investigation will determine the how changes in transcript abundance and enzyme activity control the recycling of these antioxidant metabolites.
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1 - University of Illinois at Urbana Champaign, Institute for Genomic Biology, 1207 W Gregory Drive, Urbana, IL, 61801, USA
2 - University of Illinois at Urbana Champaign, Department of Molecular Cell Biology
3 - University of Illinois at Urbana Champaign, Institute for Genomic Biology
4 - University of Illinois at Urbana Champaign, USDA Photosynthesis Research Unit
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM