Cloning, Antisense RNA Inhibition, and the Coordinated Expression of UDP-Glucose Pyrophosphorylase with Starch Biosynthetic Genes in Potato Tubers

Spychalla, James P.; Scheffler, Brian E.; Sowokinos, Joseph R.; Bevan, Michael W.

doi:10.1016/s0176-1617(11)82121-8

Cited by 62 publications

(54 citation statements)

References 31 publications

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“…The enzymic activity\protein content of UGPase increases with phosphate deficiency stress via regulation at the gene expression level [6]. In addition, expression of the gene for UGPase might be susceptible to regulation by high sucrose concentration and low temperature, as found for a UGPase gene from potato tubers [7,8], but the exact nature of the signal and its physiological significance are uncertain. Apart from that, no other significant regulatory mechanisms, either at the gene or the enzymic level, have been reported.…”

Section: Introductionmentioning

confidence: 71%

“…In contrast, Spychalla et al [7] failed to engineer potato plants with an inhibition of enzyme activity greater than 30 % ; however, this level of inhibition was sufficient to decrease sugar content in stored tubers. In other studies, storage of tubers from transgenic potato plants with a 50 % decreased UGPase activity resulted in decreased sucrose levels [9], which is consistent with the important role of UGPase in sugar synthesis.…”

Section: Introductionmentioning

confidence: 99%

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Sucrose and light regulation of a cold-inducible UDP-glucose pyrophosphorylase gene via a hexokinase-independent and abscisic acid-insensitive pathway in Arabidopsis

Ciereszko

Johansson

Kleczkowski

2001

Biochemical Journal

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UDP-glucose pyrophosphorylase (UGPase) is a key enzyme producing UDP-glucose, which is involved in an array of metabolic pathways concerned with, among other functions, the synthesis of sucrose and cellulose. An Arabidopsis thaliana UGPase-encoding gene, Ugp, was profoundly up-regulated by feeding sucrose to the excised leaves and by an exposure of plants to low temperature (5°C). The UGPase activity and its protein content also increased under conditions of sucrose feeding and exposure to cold. The sucrose effect on Ugp was apparently specific and was mimicked by exposure of dark-adapted leaves to light. Drought and O2 deficiency had some down-regulating effects on expression of Ugp. The sugar-signalling pathway for Ugp regulation was independent of hexokinase, as was found by using transgenic plants with increased and decreased expression of the corresponding gene. Subjecting mutants deficient in abscisic acid (ABA) to cold stress conditions had no effect on Ugp expression profiles. Okadaic acid was a powerful inhibitor of Ugp expression, whereas it up-regulated the gene encoding sucrose synthase (Sus1), indicating distinct transduction pathways in transmitting the sugar signal for the two genes in A. thaliana. We suggest that Ugp gene expression is mediated via a hexokinase-independent and ABA-insensitive pathway that involves an okadaic acid-responsive protein phosphatase. The data point towards Ugp as a possible regulatory entity that is closely involved in the homoeostatic readjustment of plant responses to environmental signals.

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Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Sucrose and light regulation of a cold-inducible UDP-glucose pyrophosphorylase gene via a hexokinase-independent and abscisic acid-insensitive pathway in Arabidopsis

Ciereszko

Johansson

Kleczkowski

2001

Biochemical Journal

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“…In addition, this pathway may be ubiquitous in plants unrelated to RFO and it may offer a pathway for UDP-Gal metabolism alternative to the UT pathway. The novel enzyme may play a role in Glc-1-P/UDP-Glc metabolism in general, and it is tempting to see in this alternative pathway an explanation for the lack of striking phenotypes in transgenic antisense UGPase plants (Zrenner et al, 1993;Spychalla et al, 1994). Furthermore, the homologous enzyme from pea seed was characterized in detail for specificity with respect to the sugar moiety of the sugar-phosphate substrate, and it shows activity also toward the pentoses, Ara and Xyl, suggesting possible involvement in pentose salvaging and cell wall metabolism (Kotake et al, 2004).…”

mentioning

confidence: 99%

Cloning and Expression Analysis of a UDP-Galactose/Glucose Pyrophosphorylase from Melon Fruit Provides Evidence for the Major Metabolic Pathway of Galactose Metabolism in Raffinose Oligosaccharide Metabolizing Plants

et al. 2006

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The Cucurbitaceae translocate a significant portion of their photosynthate as raffinose and stachyose, which are galactosyl derivatives of sucrose. These are initially hydrolyzed by a-galactosidase to yield free galactose (Gal) and, accordingly, Gal metabolism is an important pathway in Cucurbitaceae sink tissue. We report here on a novel plant-specific enzyme responsible for the nucleotide activation of phosphorylated Gal and the subsequent entry of Gal into sink metabolism. The enzyme was antibody purified, sequenced, and the gene cloned and functionally expressed in Escherichia coli. The heterologous protein showed the characteristics of a dual substrate UDP-hexose pyrophosphorylase (PPase) with activity toward both Gal-1-P and glucose (Glc)-1-P in the uridinylation direction and their respective UDP-sugars in the reverse direction. The two other enzymes involved in Glc-P and Gal-P uridinylation are UDP-Glc PPase and uridyltransferase, and these were also cloned, heterologously expressed, and characterized. The gene expression and enzyme activities of all three enzymes in melon (Cucumis melo) fruit were measured. The UDP-Glc PPase was expressed in melon fruit to a similar extent as the novel enzyme, but the expressed protein was specific for Glc-1-P in the UDP-Glc synthesis direction and did not catalyze the nucleotide activation of Gal-1-P. The uridyltransferase gene was only weakly expressed in melon fruit, and activity was not observed in crude extracts. The results indicate that this novel enzyme carries out both the synthesis of UDP-Gal from Gal-1-P as well as the subsequent synthesis of Glc-1-P from the epimerase product, UDP-Glc, and thus plays a key role in melon fruit sink metabolism.

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“…Control coefficients were calculated over a range of UGPase activities from 35 to 75 IU/g fresh weight. Control coefficient values ranging from 0.48 to 0.58 calculated by Spychalla et al (1994) suggested that UGPase would exert significant control on the flux of carbons toward Suc during postharvest conditions. Two nucleotide sequences of potato tuber UGPasecDNAs have been published (Katsube et al, 1990;Spychalla et al, 1994).…”

mentioning

confidence: 99%

“…Their restriction maps are shown in Figure 2. The UGPase-cDNA clone isolated by Spychalla et al (1994), designated UP2, contained 1701 bp and an ORF of 1431 bp coding for a polypeptide of 477 amino acids. The length of the ORF and the position of the polyadenylation signal corresponded exactly to that of the potato tuber UGPase cDNA clone, U4a, which was isolated by Katsube et al (1990).…”

mentioning

confidence: 99%

Pyrophosphorylases in Potato (V. Allelic Polymorphism of UDP-Glucose Pyrophosphorylase in Potato Cultivars and Its Association with Tuber Resistance to Sweetening in the Cold)

1997

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Cloning, Antisense RNA Inhibition, and the Coordinated Expression of UDP-Glucose Pyrophosphorylase with Starch Biosynthetic Genes in Potato Tubers

Cited by 62 publications

References 31 publications

Sucrose and light regulation of a cold-inducible UDP-glucose pyrophosphorylase gene via a hexokinase-independent and abscisic acid-insensitive pathway in Arabidopsis

Sucrose and light regulation of a cold-inducible UDP-glucose pyrophosphorylase gene via a hexokinase-independent and abscisic acid-insensitive pathway in Arabidopsis

Cloning and Expression Analysis of a UDP-Galactose/Glucose Pyrophosphorylase from Melon Fruit Provides Evidence for the Major Metabolic Pathway of Galactose Metabolism in Raffinose Oligosaccharide Metabolizing Plants

Pyrophosphorylases in Potato (V. Allelic Polymorphism of UDP-Glucose Pyrophosphorylase in Potato Cultivars and Its Association with Tuber Resistance to Sweetening in the Cold)

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