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

Arabidopsis thaliana ecotype Columbia was transformed with a maize sucrose phosphate synthase (SPS) cDNA under the control of the promoter for the small subunit of ribulose-1 ,5-bisphosphate carboxylase from tobacco (rbcS). The effects of SPS over-expression were compared in plants of the T 2 and T 3 generations grown either in air or with CO 2 enrichment (700 μl l -1 ) for either 4 or 10 weeks. Maximal extractable foliar SPS activities were three times those of the untransformed controls in the highest rbcS-SPS expressing line. In untransformed Arabidopsis leaves SPS activity was not subject to light/dark regulation, but was modified by incubation with either the inhibitor, orthophosphate, or the activator, mannose. Photosynthesis (A max ) values were similar in all lines grown in air. After 10 weeks of CO 2 enrichment a decrease in A max in the untransformed controls, but not in the high SPS expressors, was observed. There was a strong correlation between the sucrose-to- starch ratio of the leaves and their SPS activity in both growth conditions. The total foliar carbohydrate contents of 4-week-old plants was similar in all lines whether plants were grown in air or with CO 2 enrichment. After 10 weeks growth the leaves of the high rbcS-SPS expressors accumulated much less total carbohydrate than untransformed control leaves in both growth conditions. It was concluded that SPS over-expression causes increased foliar sucrose/starch ratios in Arabidopsis leaves and favours decreased foliar carbohydrate contents when plants are grown for long periods with CO 2 enrichment.

[1]  T. Sharkey,et al.  Sucrose-phosphate synthase activity and yield analysis of tomato plants transformed with maize sucrose-phosphate synthase , 1997, Planta.

[2]  F. H. Andrade.  Photoassimilate distribution in plants and crops: Source-sink relationships , 1997 .

[3]  R. Furbank,et al.  Adenosine 5′-triphosphate-mediated activation of sucrose-phosphate synthase in bundle sheath cells of C4 plants , 1997, Planta.

[4]  K. Koch.  CARBOHYDRATE-MODULATED GENE EXPRESSION IN PLANTS. , 1996, Annual review of plant physiology and plant molecular biology.

[5]  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.

[6]  S. Huber,et al.  Characterization of the substrate specificity of sucrose-phosphate synthase protein kinase. , 1995, Archives of biochemistry and biophysics.

[7]  B. Kimball,et al.  Increased Accumulation of Carbohydrates and Decreased Photosynthetic Gene Transcript Levels in Wheat Grown at an Elevated CO2 Concentration in the Field , 1995, Plant physiology.

[8]  D. Wilkins,et al.  Regulation of the expression of photosynthetic nuclear genes by CO2 is mimicked by regulation by carbohydrates: a mechanism for the acclimation of photosynthesis to high CO2? , 1994 .

[9]  M. Stitt,et al.  Sucrose‐phosphate synthase phosphatase, a type 2A protein phosphatase, changes its sensitivity towards inhibition by inorganic phosphate in spinach leaves , 1993, FEBS letters.

[10]  M. Stitt,et al.  Regulation of the Expression of Rbcs and Other Photosynthetic Genes by Carbohydrates - a Mechanism for the Sink Regulation of Photosynthesis , 1993 .

[11]  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.

[12]  S. Huber,et al.  Identification of factors regulating the phosphorylation status of sucrose-phosphate synthase in vivo. , 1992, Plant physiology.

[13]  S. Huber,et al.  Role of sucrose-phosphate synthase in sucrose metabolism in leaves. , 1992, Plant physiology.

[14]  J. Stougaard,et al.  Lotus japonicus, an autogamous, diploid legume species for classical and molecular genetics , 1992 .

[15]  J. Huber,et al.  Site-specific serine phosphorylation of spinach leaf sucrose-phosphate synthase. , 1992, Biochemical Journal.

[16]  M. Stitt,et al.  Sucrose-6-Phosphate Levels in Spinach Leaves and Their Effects on Sucrose-Phosphate Synthase , 1992 .

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

[18]  B. Cambou,et al.  Sucrose phosphate synthase, a key enzyme for sucrose biosynthesis in plants: protein purification from corn leaves and immunological detection. , 1991, Plant physiology.

[19]  M. Stitt,et al.  Sucrose‐phosphate synthase is dephosphorylated by protein phosphatase 2A in spinach leaves , 1990, FEBS letters.

[20]  M. Stitt,et al.  Photosynthetic carbon partitioning: its regulation and possibilities for manipulation , 1989 .

[21]  M. Stitt,et al.  Control Analysis of Photosynthetic Sucrose Synthesis - Assignment of Elasticity Coefficients and Flux-Control Coefficients to the Cytosolic Fructose 1,6-Bisphosphatase and Sucrose Phosphate Synthase , 1989 .

[22]  D. M. Pharr,et al.  Variation among Species in Light Activation of Sucrose-Phosphate Synthase , 1989 .

[23]  T. Sharkey,et al.  Acclimation of Photosynthesis to Elevated CO(2) in Five C(3) Species. , 1989, Plant physiology.

[24]  M. Stitt,et al.  Limitation of Photosynthesis by Carbon Metabolism : I. Evidence for Excess Electron Transport Capacity in Leaves Carrying Out Photosynthesis in Saturating Light and CO(2). , 1986, Plant physiology.

[25]  R. Sicher,et al.  Possible control of maize leaf sucrose-phosphate synthase activity by light modulation. , 1985, Plant physiology.

[26]  T. Sharkey,et al.  O(2)-insensitive photosynthesis in c(3) plants : its occurrence and a possible explanation. , 1985, Plant physiology.

[27]  S. Huber,et al.  Regulation of Spinach Leaf Sucrose Phosphate Synthase by Glucose-6-Phosphate, Inorganic Phosphate, and pH. , 1983, Plant physiology.

[28]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[29]  L. Vernon.  Spectrophotometric Determination of Chlorophylls and Pheophytins in Plant Extracts , 1960 .

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

[31]  M. Stitt,et al.  Regulation of metabolism in transgenic plants , 1995 .

[32]  M. Stitt,et al.  Partial purification of two forms of spinach leaf sucrose-phosphate synthase which differ in their kinetic properties , 1990 .

[33]  S. Huber,et al.  Light modulation of maize leaf sucrose phosphate synthase , 1987 .

[34]  C. Foyer,et al.  Regulation of the Benson-Calvin cycle , 1985 .

[35]  G. Salerno,et al.  A procedure for the assay of sucrose synthetase and sucrose phosphate synthetase in plant homogenates. , 1979, Analytical biochemistry.

[36]  D. Arnon.  COPPER ENZYMES IN ISOLATED CHLOROPLASTS. POLYPHENOLOXIDASE IN BETA VULGARIS. , 1949, Plant physiology.