On the role of chloroplastic phosphoglucomutase in the regulation of starch turnover

Hattenbach, A.; Heineke, Dieter

doi:10.1007/s004250050513

Cited by 19 publications

(11 citation statements)

References 28 publications

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“…The plastidic PGM is essential for starch synthesis to store photosynthates in leaves during the day, and in the degradation of starch [44]. The cytosolic PGM is involved in sucrose catabolism to provide intermediates for glycolysis, citric acid cycle, fatty acid, amino acid, glyoxylic acid cycle etc metabolic pathways [45].…”

Section: Resultsmentioning

confidence: 99%

Horticultural Production of Ultra High Resveratrol Peanut

Osuji¹,

Johnson²,

Duffus³

et al. 2017

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Background: Resveratrol naturally occurring antioxidant in peanut (Legume:Arachis hypogaea) has phytochemical human health dietary effects associated with reduced inflammatory cancer risks. Its levels in peanut are ultra-low and variable (0 to 26 µg•g −1 ), which has made it difficult to market as a consistent high resveratrol produce. Objective: Understanding the regulation of resveratrol accumulation in peanut might lead to development of new techniques for optimizing and stabilizing its yield. Method: Peanuts were cultivated in horticultural field plots and treated with solutions of mineral salts (sulfate, potassium, phosphate, ammonium ion) that were optimized in stoichiometric (reactive) ratios. Peanut seed's RNAs were subjected to Northern blot analysis for profiling the RNAs synthesized by glutamate dehydrogenase (GDH), and mRNAs encoding resveratrol synthase. The seed's extracts were analyzed by GC-MS for determination of the resveratrol and fatty acid compositions. Result: Stoichiometric mixes of mineral ions induced the peanut GDH to synthesize some RNA that silenced the mRNAs encoding resveratrol synthase, phosphoglucomutase, isocitrate lyase, malate synthase, enolase, phosphoenolpyruvate carboxylase, malate dehydrogenase, and phosphoglycerate mutase in the control, KN-, and NPKS-treated but not in the NPPK-treated peanut. These resulted to decreased resveratrol content (6.0 µg•g −1

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Section: Resultsmentioning

confidence: 99%

Horticultural Production of Ultra High Resveratrol Peanut

Osuji¹,

Johnson²,

Duffus³

et al. 2017

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“…It is possible that due to the displacement of the Glc6P/Fru6P and Glc1P/Glc6P ratios from equilibrium by a factor of 2±3 in chloroplasts, phosphoglucomutase as well as phosphoglucose isomerase might become rate limiting for photosynthetic starch synthesis (Neuhaus and Stitt 1990). This, in turn, could restrict the carbon exchange between the Calvin cycle and starch turnover (Hattenbach and Heineke 1999).…”

Section: Discussionmentioning

confidence: 99%

Cold acclimation of Arabidopsis thaliana results in incomplete recovery of photosynthetic capacity, associated with an increased reduction of the chloroplast stroma

Savitch

Barker-Astrom

Ivanov

et al. 2001

Planta

115

102

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The effects of short-term cold stress and long-term cold acclimation on the light reactions of photosynthesis were examined in vivo to assess their contributions to photosynthetic acclimation to low temperature in Arabidopsis thaliana (L.) Heynh.. All photosynthetic measurements were made at the temperature of exposure: 23 degrees C for non-acclimated plants and 5 degrees C for cold-stressed and cold-acclimated plants. Three-day cold-stress treatments at 5 degrees C inhibited light-saturated rates of CO2 assimilation and O2 evolution by approximately 75%. The 3-day exposure to 5 degrees C also increased the proportion of reduced QA by 50%, decreased the yield of PSII electron transport by 65% and decreased PSI activity by 31%. In contrast, long-term cold acclimation resulted in a strong but incomplete recovery of light-saturated photosynthesis at 5 degrees C. The rates of light-saturated CO2 and O2 gas exchange and the in vivo yield of PSII activity under light-saturating conditions were only 35-40% lower, and the relative redox state of QA only 20% lower, at 5 degrees C after cold acclimation than in controls at 23 degrees C. PSI activity showed full recovery during long-term cold acclimation. Neither short-term cold stress nor long-term cold acclimation of Arabidopsis was associated with a limitation in ATP, and both treatments resulted in an increase in the ATP/NADPH ratio. This increase in ATP/NADPH was associated with an inhibition of PSI cyclic electron transport but there was no apparent change in the Mehler reaction activity in either cold-stressed or cold-acclimated leaves. Cold acclimation also resulted in an increase in the reduction state of the stroma, as indicated by an increased total activity and activation state of NADP-dependent malate dehydrogenase, and increased light-dependent activities of the major regulatory enzymes of the oxidative pentose-phosphate pathway. We suggest that the photosynthetic capacity during cold stress as well as cold acclimation is altered by limitations at the level of consumption of reducing power in carbon metabolism.

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“…However, the synthesis of starch must be considered as far more than a way of coping with an excess of photosynthate (Geiger et al 2000), and there are undoubtedly mechanisms other than just the ratio of PGA:Pi (Preiss 1980) that regulate starch synthesis, for example the role of phosphoglucomutase Hattenbach and Heineke 1999). Further studies are required to examine the regulation of starch synthesis in wheat leaves.…”

Section: Regulation Of Starch Synthesis In Wheatmentioning

confidence: 97%

Regulation of sucrose and starch synthesis in wheat ( Triticum aestivum L.) leaves: role of fructose 2,6-bisphosphate

Trevanion

2002

Planta

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Fructose 2,6-bisphosphate (F26BP) is a competitive inhibitor of the cytosolic fructose 1,6-bisphosphatase (cytFBPase, EC 3.1.3.11). In spinach (Spinacia oleracea L.) leaves it is a significant component of the complex regulatory network that co-ordinates rates of photosynthesis, sucrose synthesis and starch synthesis. However the role of F26BP has only been studied in plants that predominantly store starch in their leaves and its role in other species is not clear. This paper examines the significance of F26BP in the regulation of photosynthetic carbon metabolism in the intact leaves of wheat (Triticum aestivum L.), a plant that accumulates predominantly sucrose. The approach taken was to vary rates of photosynthesis and then correlate measurements of F26BP and a range of other metabolites with rates of carbohydrate synthesis obtained from (14)CO(2)-feeding experiments performed under physiological conditions. It was found that: (i) Amounts of 3-phosphoglycerate and fructose-6-phosphate are correlated with the amount of F26BP. (ii) F26BP is involved in inhibiting cytFBPase at low light and low CO(2), but other factors, for example triose-phosphate, must also be involved. (iii) Amounts of both F26BP and substrate are involved in co-ordinating rates of photosynthesis and sucrose synthesis, but the relative importance of these depends on the conditions. (iv) Amounts of F26BP do not correlate with the partitioning of fixed carbon between sucrose and starch. Together these data suggest that the amount of F26BP in wheat is regulated by mechanisms similar to those in spinach, and that the metabolite is one of the factors involved in co-ordinating sucrose synthesis and photosynthesis. However F26BP does not appear to be involved in regulating the partitioning of fixed carbon between sucrose and starch in wheat under the experimental conditions examined.

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On the role of chloroplastic phosphoglucomutase in the regulation of starch turnover

Cited by 19 publications

References 28 publications

Horticultural Production of Ultra High Resveratrol Peanut

Horticultural Production of Ultra High Resveratrol Peanut

Cold acclimation of Arabidopsis thaliana results in incomplete recovery of photosynthetic capacity, associated with an increased reduction of the chloroplast stroma

Regulation of sucrose and starch synthesis in wheat ( Triticum aestivum L.) leaves: role of fructose 2,6-bisphosphate

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