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Abstract Detail


Environmental Physiology

Weraduwage, Sarathi [1], Micallef, Malgre C. [2], Grodzinski, Bernard [2], Micallef, Barry J. [2].

Growth and development under elevated CO2 for Arabidopsis thaliana having altered expression of mitochondrial pyruvate dehydrogenase kinase.

Mitochondrial pyruvate dehydrogenase (mtPDH) catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA; acetyl-CoA is a central metabolite in both catabolic and anabolic processes. Activity of mtPDH is affected by its phosphorylation state through mitochondrial pyruvate dehydrogenase kinase (mtPDHK) and phosphatase. Transgenic Arabidopsis having either constitutive or seed-specific antisense repression of mtPDHK show increased seed oil content and increased seed weight. However, only the siliques of seed-specific lines show enhanced dark CO2 release, and constitutive lines have a smaller leaf rosette. We tested the following hypothesis: plants having seed-specific antisense repression of mtPDHK will show enhanced growth rates and productivity under elevated CO2 compared to controls due to greater reproductive sink strength. Lines having either constitutive or seed-specific expression of an antisense construct for mtPDHK were grown under either ambient or high (700ppm) CO2, and plant development was monitored over time. Under ambient CO2 for both constitutive and seed-specific lines, there were a reduced number of primary (1o) inflorescences and a corresponding increase in secondary and tertiary inflorescences; the height of the first 1o inflorescence also increased. Time to initiation for the first 1o inflorescence decreased for constitutive and seed-specific lines under either ambient or high CO2. Silique number increased at both ambient and elevated CO2 for seed-specific lines, but only at ambient CO2 for constitutive lines. Changes in circadian growth patterns for the inflorescence were also evident. The role of interactions between C metabolism and circadian sink activity in the control of plant development will be discussed.


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1 - University of Guelph, Plant Agriculture, Crop Science Bldg, Guelph, Ontario, N1G 2W1, Canada
2 - University of Guelph, Plant Agriculture

Keywords:
Effect of elevated CO2 on plant metabolism
C metabolism and circadian sink activity
Mitochondrial pyruvate dehydrogenase complex
Pyruvate dehydrogenase kinase
Antisense respression of mtPDHK
Arabidopsis thaliana with altered respiratory capacities.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P01040
Abstract ID:2152


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