Kaplan, Fatma , Zhao, Wei , Popp, Michael , Richards, Jeffrey , Wheeler, Raymond M. , Guy, Charles L. , Levine, Lanfang H. .
Gene Expression and Metabolite Profiling of Arabidopsis at Elevated and Super-elevated CO2 Reveal a Diminished Ability of Plants to Adjust to Super-elevated CO2 Levels.
Atmospheric CO2 concentration has direct impact on plant function and productivity. While a wealth of literature demonstrates a beneficial effect of enriching CO2 to 2-3 X current ambient on plant productivity and water use efficiency (WUE), little is known about the consequences of elevated CO2 beyond this range (e.g. > 10 X current ambient). Previous studies of several crop species in controlled environments revealed that super-elevated CO2 reduces productivity and WUE, suggesting a non-linear response to increasing CO2. In order to probe the underlying mechanism for the different effect on plants between moderately elevated and super-elevated CO2, an integrative investigation of gene and metabolite expression was conducted using Arabidopsis grown under three CO2 levels (400 as control, 1200 and 4000 ppm) and near saturating light level to 1.09 and 1.14 leaf stage. Similar to what has been reported for soybean, potato and wheat, vegetative growth was reduced and transpiration (especially at night) was increased in Arabidopsis grown at 4000 ppm CO2 compared to 1200 ppm. Genes were differentially regulated by 1200 and 4000 ppm CO2, and influenced by developmental stage. For example, the expression of genes associated with ATP synthase, NADH dehydrogenase and photosynthesis was down-regulated by 1200 ppm at 1.09, but up-regulated at 1.14, while 4000 ppm CO2 had little effect on these genes at either developmental stage. Furthermore, elevated CO2 resulted in the apparent reduction of the steady-state levels of the photorespiratory products glycine, serine and glyceric acid. The implication of these findings in plant function and productivity will be discussed.
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1 - University of Florida, Department of Biochemistry and Molecular Biology,
2 - University of California, Department of Human Genetics and Biostatistics
3 - University of Florida, Interdisciplinary Center for Biotechnology Research
4 - Dynamac Corporation at Kennedy Space Center, Space Life Sciences Laboratories
5 - Kennedy Space Center, NASA, Biological Sciences Office
6 - University of Florida, Department of Environmental Horticulture
7 - Dynamac Corporation at Kennedy Space Center, Space Life Sciences Laboratories, Kennedy Parkway and 5th Street, Mail Code: DYN-3, Kennedy Space Center, Florida, 32899, USA
Water Use Efficiency.
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM