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Over-expressing the C <inf>3 </inf> photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO <inf>2 </inf> fumigation (FACE)

Rosenthal, DM and Locke, AM and Khozaei, M and Raines, CA and Long, SP and Ort, DR (2011) 'Over-expressing the C <inf>3 </inf> photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO <inf>2 </inf> fumigation (FACE).' BMC Plant Biology, 11. ISSN 1471-2229

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Abstract

Background: Biochemical models predict that photosynthesis in C 3 plants is most frequently limited by the slower of two processes, the maximum capacity of the enzyme Rubisco to carboxylate RuBP (V c,max ), or the regeneration of RuBP via electron transport (J). At current atmospheric [CO 2 ] levels Rubisco is not saturated; consequently, elevating [CO 2 ] increases the velocity of carboxylation and inhibits the competing oxygenation reaction which is also catalyzed by Rubisco. In the future, leaf photosynthesis (A) should be increasingly limited by RuBP regeneration, as [CO 2 ] is predicted to exceed 550 ppm by 2050. The C 3 cycle enzyme sedoheptulose-1,7 bisphosphatase (SBPase, EC 3.1.3.17) has been shown to exert strong metabolic control over RuBP regeneration at light saturation.Results: We tested the hypothesis that tobacco transformed to overexpressing SBPase will exhibit greater stimulation of A than wild type (WT) tobacco when grown under field conditions at elevated [CO 2 ] (585 ppm) under fully open air fumigation. Growth under elevated [CO 2 ] stimulated instantaneous A and the diurnal photosynthetic integral (A') more in transformants than WT. There was evidence of photosynthetic acclimation to elevated [CO 2 ] via downregulation of V c,max in both WT and transformants. Nevertheless, greater carbon assimilation and electron transport rates (J and J max ) for transformants led to greater yield increases than WT at elevated [CO 2 ] compared to ambient grown plants.Conclusion: These results provide proof of concept that increasing content and activity of a single photosynthesis enzyme can enhance carbon assimilation and yield of C 3 crops grown at [CO 2 ] expected by the middle of the 21st century. © 2011 Rosenthal et al; licensee BioMed Central Ltd.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Biological Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 13 Mar 2013 20:58
Last Modified: 10 Apr 2019 10:15
URI: http://repository.essex.ac.uk/id/eprint/5839

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