tailieunhanh - báo cáo khoa học: "Over-expressing the C3 photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO2 fumigation (FACE)"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Over-expressing the C3 photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO2 fumigation (FACE) | Rosenthal et al. BMC Plant Biology 2011 11 123 http 1471-2229 11 123 BMC Plant Biology RESEARCH ARTICLE Open Access Over-expressing the C3 photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO2 fumigation FACE David M Rosenthal1 Anna M Locke2 Mahdi Khozaei3 Christine A Raines4 Stephen P Long5 and Donald R Ort6 Abstract Background Biochemical models predict that photosynthesis in C3 plants is most frequently limited by the slower of two processes the maximum capacity of the enzyme Rubisco to carboxylate RuBP Vc max or the regeneration of RuBP via electron transport J . At current atmospheric CO2 levels Rubisco is not saturated consequently elevating CO2 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 CO2 is predicted to exceed 550 ppm by 2050. The C3 cycle enzyme sedoheptulose-1 7 bisphosphatase SBPase EC 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 CO2 585 ppm under fully open air fumigation. Growth under elevated CO2 stimulated instantaneous A and the diurnal photosynthetic integral A more in transformants than WT. There was evidence of photosynthetic acclimation to elevated CO2 via downregulation of Vc max in both WT and transformants. Nevertheless greater carbon assimilation and electron transport rates J and Jmax for transformants led to greater yield increases than WT at elevated CO2 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