Expression of a Maize Sucrose Phosphate Synthase in Tomato Alters Leaf Carbohydrate Partitioning

Worrell, Ann C.; Bruneau, Jean-Michel; Summerfelt, Kristin R.; Boersig, Mike; Voelker, Toni A.

doi:10.2307/3869300

Cited by 40 publications

(67 citation statements)

References 8 publications

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“…These variations might be due to differences in culture conditions. Yet, a decrease in starch content, paralleled by an increase in sucrose, has also been observed in transgenic tomato plants expressing higher levels of SPS (Worrell et al, 1991), indicating the importance of SPS activity in C partitioning. This finding is relevant to our system, as an increase in SPS activation state was found only for mycorrhiza formation, not for increased CO # .…”

Section: Carbohydrate Metabolism In Shootsmentioning

confidence: 99%

Mycorrhiza formation and elevated CO₂ both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

et al. 2000

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The effects of mycorrhiza formation in combination with elevated CO # concentrations on carbon metabolism of Norway spruce (Picea abies) seedlings and aspen (Populus tremulaiPopulus tremuloides) plantlets were analysed. Plants were inoculated for 6 wk with the ectomycorrhizal fungi Amanita muscaria and Paxillus involutus (aspen only) in an axenic Petri-dish culture at 350 and 700 µl l −" CO # partial pressure. After mycorrhiza formation, a stimulation of net assimilation rate was accompanied by decreased activities of sucrose synthase, an increased activation state of sucrose-phosphate synthase, decreased fructose-2,6-bisphosphate and starch, and slightly elevated glucose-6-phosphate contents in source leaves of both host species, independent of CO # concentration. Exposure to elevated CO # generally resulted in higher net assimilation rates, increased starch as well as decreased fructose-2,6-bisphosphate (aspen only) content in source leaves of both mycorrhizal and nonmycorrhizal plants. Our data indicate only slightly improved carbon utilization by mycorrhizal plants at elevated CO # . They demonstrate however, that both factors which modulate the sink-source properties of plants increase the capacity for sucrose synthesis in source leaves mainly by allosteric enzyme regulation.

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Section: Carbohydrate Metabolism In Shootsmentioning

confidence: 99%

Mycorrhiza formation and elevated CO₂ both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

et al. 2000

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“…In C 3 -plants, PEPC acts to replenish TCA cycle intermediates which serve as source material for the synthesis of amino acids (Stitt 1999). On the other hand, C distribution to sucrose increases with rising SPS levels (Worrel et al 1991, Signora et al 1998, Murchie et al 1999. Galtier et al (1993) demonstrated a positive relationship between SPS activity and the sucrose/starch ratio by changing the level of SPS in tomato transformed with a maize SPS gene, resulting in increased starch degradation in the chloroplasts.…”

Section: Introductionmentioning

confidence: 99%

Developmental regulation of photosynthate distribution in leaves of rice

Shinano

Nakajima²,

Wasaki

et al. 2006

Photosynt.

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AbstractmRNA expression patterns of genes for metabolic key-enzymes (sucrose phosphate synthase [SPS], phosphoenolpyruvate carboxylase [PEPC], pyruvate kinase, ribulose 1,5-bisphosphate carboxylase/oxygenase, glutamine synthetase 1, and glutamine synthetase 2) were investigated in leaves of rice plants grown at two nitrogen (N) concentrations. The relative gene expression patterns were similar in all leaves except for 9 th leaf, in which mRNA levels were generally depressed.Though an increased N concentrations prolonged the expression period of each mRNA, it did not affect the relative expression intensity of any mRNA in a given leaf. SPS V max , SPS limiting activity, PEPC activity, and carbon flow were examined using 14 CO 2 . The ratio between PEPC activity and SPS V max was higher in leaves developed at the vegetative growth stage (vegetative leaves: 5 th and 7 th 1 leaf) than in leaves developed after the ear primordia formation stage (reproductive leaves: 9 th and flag leaf). PEPC activity and SPS V max decreased with declining leaf N concentration. The 14 C photosynthate distribution to the amino acids fraction was higher in vegetative than in reproductive leaves when compared for the same leaf N status. Thus, at high PEPC activity to SPS activity ratio, more 14 C photosynthate was distributed to the amino acid pool, whereas at higher SPS activity, more 14 C was channeled into the carbohydrate fraction. Thus, leaf ontogeny was an important factor controlling photosynthate distribution to the Nor C-pool, respectively, regardless of leaf N status.

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“…This fact may provide an explanation for the perturbations in carbon metabolism observed in these plants (Worrell et al, 1991). For example, increased activities of SPS were shown to modify assimilate partitioning in the leaf (Worrell et al, 1991). We have studied the metabolic and physiological effects of the expression of the maize gene in the next generation of tomato plants (the TI generation, grown from seed).…”

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confidence: 99%

“…It has been shown that the generation of one type of subunit (molecular mass 135 kD) is sufficient to assemble the SPS holoenzyme in Escherichia coli (Worrell et al, 1991).…”

mentioning

confidence: 99%

“…The maize leaf SPS has been shown to be subject to light/dark regulation (Kalt-Torres and Huber, 1987), a process mediated by phosphorylation of the enzyme protein (Huber and Huber, 1991; Huber et al, 1991). It has been shown that the generation of one type of subunit (molecular mass 135 kD) is sufficient to assemble the SPS holoenzyme in Escherichia coli (Worrell et al, 1991).Transgenic tomato (Lycopersicon esculentum) plants expressing both the native SPS and also the SPS gene from maize were produced by Worrell et al (1991). The active enzyme was expressed from cloned cDNA under the control of the promoter for the gene encoding the small subunit of ribulose-1,5-bisphosphate carboxylase from tobacco (Nicotiana tabacum) (Worrell et al, 1991).…”

mentioning

confidence: 99%

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Effects of Elevated Sucrose-Phosphate Synthase Activity on Photosynthesis, Assimilate Partitioning, and Growth in Tomato (Lycopersicon esculentum var UC82B)

Galtier¹,

Foyer²,

Huber³

et al. 1993

Plant Physiol.

162

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The expression of a sucrose-phosphate synthase (SPS) gene from maize (Zea mays, a monocotyledon) in tomato (Lycopersicon esculenfum, a dicotyledon) resulted i n marked increases in extractable SPS activity in the light and the dark. Diurna1 modulation of the native tomato SPS activity was found. However, when the maize enzyme was present the tomato leaf cells were unable to regulate its activation state. No detrimental effects were observed and total dry matter production was unchanged. However, carbon allocation within the plants was modified such that in shoots it increased, whereas in roots it decreased. There was, therefore, a change in the shootroot dry weight ratio favoring the shoot. This was positively correlated with increased SPS activity in leaves. SPS was a major determinant of the amount of starch i n leaves as well as sucrose. There was a strong positive correlation between the ratio of sucrose to starch and SPS activity in leaves. Therefore, SPS activity is a major determinant of the partitioning of photosynthetically fixed carbon in the leaf and in the whole plant. The photosynthetic rate in air was not significantly increased as a result of elevated leaf SPS activity. However, the light-and C02-saturated rate of photosynthesis was increased by about 20% in leaves expressing high SPS. In addition, the temporary enhancement of the photosynthetic rate following brief exposures to low light was increased in the high SPS plants relative to controls. We conclude that the leve1 of SPS in the leaves plays a pivotal role in carbon partitioning. Furthermore, high SPS levels have the potential to boost photosynthetic rates under favorable conditions. ~ ~~~~~~~~ SPS catalyzes the penultimate step of sucrose biosynthesis in leaves (Pontis, 1977). This rate-limiting, allosteric enzyme forms a major control point subject to regulation by metabolites and by covalent modification involving protein phosphorylation (Harbron et al., 1981; Huber, 1983;Stitt et al., 1987;Huber et al., 1989;Stitt and Quick, 1989). The activity of this enzyme can be a limiting factor for de novo SUC synthesis and also photosynthesis (Pontis, 1977; Huber, 1983;Stitt et al., 1987). The amount of extractable SPS activity is known to vary in response to light/dark transitions (Huber et al., 1987) and to the metabolic status of the leaf tissue in terms of substrate concentrations (Harbron et al., 1981; Huber, 1983; Kalt-Torres and Huber, 1987;Kerr and Huber, 1987;Stitt et al., 1987).* Corresponding author; fax 33-30-83-30-96. Multiple forms of SPS have been observed in leaves of plants such as maize (Kalt-Torres et al., 1987). The multiplicity of enzyme forms appears to arise from posttranslational modifications (Huber et al., 1989; Huber and Huber, 1991) to the enzyme protein because the cDNA isolated from maize appears to have only one predominant species of transcript (Worrell et al., 1991). The maize leaf SPS has been shown to be subject to light/dark regulation (Kalt-Torres and Huber, 1987), a process mediated by phosphorylation ...

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Expression of a Maize Sucrose Phosphate Synthase in Tomato Alters Leaf Carbohydrate Partitioning

Cited by 40 publications

References 8 publications

Mycorrhiza formation and elevated CO₂ both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

Mycorrhiza formation and elevated CO₂ both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

Developmental regulation of photosynthate distribution in leaves of rice

Effects of Elevated Sucrose-Phosphate Synthase Activity on Photosynthesis, Assimilate Partitioning, and Growth in Tomato (Lycopersicon esculentum var UC82B)

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Expression of a Maize Sucrose Phosphate Synthase in Tomato Alters Leaf Carbohydrate Partitioning

Cited by 40 publications

References 8 publications

Mycorrhiza formation and elevated CO2 both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

Mycorrhiza formation and elevated CO2 both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

Developmental regulation of photosynthate distribution in leaves of rice

Effects of Elevated Sucrose-Phosphate Synthase Activity on Photosynthesis, Assimilate Partitioning, and Growth in Tomato (Lycopersicon esculentum var UC82B)

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Mycorrhiza formation and elevated CO₂ both increase the capacity for sucrose synthesis in source leaves of spruce and aspen

Mycorrhiza formation and elevated CO₂ both increase the capacity for sucrose synthesis in source leaves of spruce and aspen