Changes in Photosynthetic Activity and Export of Carbon by Overexpressing a Maize Sucrose-Phosphate Synthase Gene under Elevated C02 in Transgenic Rice

Abstract To investigate whether increased sucrose-phosphate synthase (SPS) activity alters photosynthetic activity and/or the export of carbon from leaves under elevated C02 partial pressure ([C02]), we raised two lines of transgenic rice (H54-9 and H69-7), each overexpressing a maize SPS gene, and wild-type rice under ambient [C02] (35 Pa) and elevated [0O2] (100 Pa). Under ambient [C02], no significant difference was observed between the transgenic and wild-type plants in the levels of sucrose or starch in leaves or the photosynthetic activity; but the carbon export rate was higher in H69-7 than in the wild-type. Under elevated [C02], photosynthetic activity increased in all plants, but the accumulation of starch was significantly repressed in H54-9, whose SPS activity was about 12.5 times higher than that of the wild-type. The carbon export rate was higher in both transgenic lines than the wild-type. We considered that increased SPS activity in rice plants would promote the export of carbon from leaves and, as a result, starch accumulation in the leaves would be suppressed and/or photosynthetic activity would be promoted under elevated [CO2].

[1]  G. Bowes,et al.  Up-regulation of sucrose phosphate synthase in rice grown under elevated CO2 and temperature , 1999, Photosynthesis Research.

[2]  S. Wong.  Elevated atmospheric partial pressure of CO2 and plant growth , 1990, Photosynthesis Research.

[3]  A. Makino,et al.  Differences between wheat and rice in the enzymic properties of ribulose-1,5-bisphosphate carboxylase/oxygenase and the relationship to photosynthetic gas exchange , 1988, Planta.

[4]  S. Wong,et al.  Elevated atmospheric partial pressure of CO2 and plant growth , 1979, Oecologia.

[5]  N. Aoki,et al.  Effects of Elevated CO2 Concentration on Photosynthetic Carbon Metabolism in Flag-Leaf Blades of Rice before and after Heading , 2003 .

[6]  N. Aoki,et al.  Characterization of a Maize Sucrose–phosphate Synthase Protein and Its Effect on Carbon Partitioning in Transgenic Rice Plants , 1999 .

[7]  C. Foyer,et al.  Overexpression of sucrose-phosphate synthase in tomato plants grown with CO2 enrichment leads to decreased foliar carbohydrate accumulation relative to untransformed controls , 1999 .

[8]  J. Seemann,et al.  Sucrose cycling, Rubisco expression, and prediction of photosynthetic acclimation to elevated atmospheric CO2 , 1998, Plant, Cell & Environment.

[9]  C. Foyer,et al.  Over-expression of sucrose phosphate synthase in Arabidopsis thaliana results in increased foliar sucrose/starch ratios and favours decreased foliar carbohydrate accumulation in plants after prolonged growth with CO2 enrichment , 1998 .

[10]  A. Makino,et al.  The Effect of Elevated Partial Pressures of CO2 on the Relationship between Photosynthetic Capacity and N Content in Rice Leaves , 1997, Plant physiology.

[11]  M. D. Hatch,et al.  The Role of Sucrose-Phosphate Synthase in the Control of Photosynthate Partitioning in Zea mays Leaves , 1997 .

[12]  Steven C. Huber,et al.  ROLE AND REGULATION OF SUCROSE-PHOSPHATE SYNTHASE IN HIGHER PLANTS. , 1996, Annual review of plant physiology and plant molecular biology.

[13]  P. Quick,et al.  Effects of light and atmospheric carbon dioxide enrichment on photosynthesis and carbon partitioning in the leaves of tomato (Lycopersicon esculentum L.) plants over-expressing sucrose phosphate synthase , 1995 .

[14]  J. Conroy,et al.  Diurnal Regulation of Leaf Blade Elongation in Rice by CO2 (Is it Related to Sucrose-Phosphate Synthase Activity?) , 1995, Plant physiology.

[15]  J. Watson,et al.  Characterization of a cDNA Encoding Ribosomal Protein S16 in Rice , 1995, Plant physiology.

[16]  R. Gifford,et al.  Photosynthetic Acclimation in Pea and Soybean to High Atmospheric CO2 Partial Pressure , 1994, Plant physiology.

[17]  C. Foyer,et al.  Effects of Elevated Sucrose-Phosphate Synthase Activity on Photosynthesis, Assimilate Partitioning, and Growth in Tomato (Lycopersicon esculentum var UC82B) , 1993, Plant physiology.

[18]  M. Boersig,et al.  Expression of a maize sucrose phosphate synthase in tomato alters leaf carbohydrate partitioning. , 1991, The Plant cell.

[19]  J. Sheen,et al.  Metabolic repression of transcription in higher plants. , 1990, The Plant cell.

[20]  A. Gosselin,et al.  Acclimation of Two Tomato Species to High Atmospheric CO(2): I. Sugar and Starch Concentrations. , 1989, Plant physiology.

[21]  M. Peet,et al.  Acclimation to High CO(2) in Monoecious Cucumbers : II. Carbon Exchange Rates, Enzyme Activities, and Starch and Nutrient Concentrations. , 1986, Plant physiology.

[22]  E. DeLucia,et al.  Reversibility of Photosynthetic Inhibition in Cotton after Long-Term Exposure to Elevated CO(2) Concentrations. , 1985, Plant physiology.