Regulation of the formation and utilization of photosynthate in leaves

Cséke, Csaba; Buchanan, Bob B.

doi:10.1016/0304-4173(86)90004-2

Cited by 124 publications

(67 citation statements)

References 124 publications

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“…ADPGlc-PPiase activity is exclusively localized in the plastids (Table IA) as is the case in green tissues (22 NADP-dependent GAPDH has been used as a marker enzyme for plastids (28) as is usually done for chloroplastcontaining tissues (3). Its activity on a protein basis is higher in etioplasts than in the crude extracts because of the effect of organelle purification (Table 1A).…”

Section: Synthesis Of Adpglcmentioning

confidence: 99%

Transport Processes and Corresponding Changes in Metabolite Levels in Relation to Starch Synthesis in Barley (Hordeum vulgare L.) Etioplasts

Bätz

Scheibe²,

Neuhaus³

1992

Plant Physiol.

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Section: Synthesis Of Adpglcmentioning

confidence: 99%

Transport Processes and Corresponding Changes in Metabolite Levels in Relation to Starch Synthesis in Barley (Hordeum vulgare L.) Etioplasts

Bätz

Scheibe²,

Neuhaus³

1992

Plant Physiol.

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“…The ferredoxin gene product is a low molecular weight iron-sulphur protein that functions as electron carrier in a variety of redox reactions (Lea and Miflin, 1974;Ramirez et a/., 1966;Schmidt and Trebst, 1969). Furthermore, ferredoxin is part of the ferredoxinl thioredoxin system which regulates plastidic carbon metabolism (Cseke and Buchanan, 1986). Kaufman et a/.…”

Section: Introductionmentioning

confidence: 99%

Light-regulated expression of the Arabidopsis thaliana ferredoxin A gene involves both transcriptional and post-transcriptional processes

Vorst¹,

Dam²,

Weisbeek³

et al. 1993

Plant J

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SummaryFerredoxin is part of the photosynthetic apparatus of the chloroplast and is encoded in the nucleus. In Arabidopsis thaliana expression of the ferredoxin A gene is influenced by both the presence of chloroplasts and light. Tobacco plants transformed with a ferredoxin promoter-GUS fusion gene showed a tissue-specific and light-dependent expression pattern. The effect of light on the expression of the fusion gene in transgenic seedlings was only two-to fourfold, which is less pronounced than the 20-fold effect in Arabidopsis itself. Run-on transcription assays with nuclei isolated from Arabidopsis revealed a twofold modulation of transcriptional activity of the ferredoxin A gene under the influence of light. These results suggest the involvement of post-transcriptional processes in lightregulated gene expression.A ferredoxin promoter deletion series ranging from -1205 to -143 was studied. All but the smallest deletion construct (at position -143 relative to the translation start site) showed comparable expression levels in mature leaves, suggesting the presence of a positive regulating element between -269 and -143. The same pattern of tissue specificity was found in all promoter deletions studied. Expression of the fusion genes is high in all chloroplast-containing cells: mesophyll, chlorenchyma, paravascular tissue, epidermal and stomata1 guard cells and trichomes. Transgenic seedlings treated with norflurazon, which blocks the development of green chloroplasts, showed a two-to fourfold reduction in GUS expression for all constructs. In Arabidopsis seedlings the effect of norflurazon on the expression of the ferredoxin A was eightfold. This again can be explained by the need for post-transcriptional processes of the regulated gene expression of Arabidopsis ferredoxin A.

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“…Although both feed-forward and feedback mechanisms are well characterized in vitro (1,2,4,8,9,16,17), the relative extent of the influence of each in vivo is unclear (4,8 …”

Section: Introductionmentioning

confidence: 99%

“…Measurements in intact leaves, however, would suggest that the degree of control in vivo exerted by this limitation on plastoquinol oxidation is relatively constant with respect to irradiance in air (4, 14), although not in the absence of CO2 (11). In addition, it has been demonstrated that the acidification of the thylakoid lumen also has direct effects on the quantum efficiency of PSII (9, 30).Although both feed-forward and feedback mechanisms are well characterized in vitro (1,2,4,8,9,16,17), the relative extent of the influence of each in vivo is unclear (4,8 …”

mentioning

confidence: 99%

Control of the Quantum Efficiencies of Photosystems I and II, Electron Flow, and Enzyme Activation following Dark-to-Light Transitions in Pea Leaves

Foyer

Lelandais²,

Harbinson³

1992

Plant Physiol.

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The quantum efficiencies of photosystems I and 11 (PSI and PSII), [NADP]/[NADPH] ratios, and the activities of chloroplastic fructose-1,6-bisphosphatase and NADP-malate dehydrogenase were measured in intact pea (Pisum sativum L.) leaves in air following the transition from darkness to 750 microeinsteins per square meter per second irradiance. PSII efficiency declined from a low value to a minimum within the first 10 to 15 seconds of irradiance, after which it increased progressively to the steady-state value. The resistance of electron flow between the photosystems was high at this time, but it was not the principal factor limiting electron flow. Oxidation of P700 was restricted by acceptor side processes for approximately the first 60 seconds of illumination. Once the acceptor side limitation was relieved, the oxidation state of P700 was used to estimate the quantum efficiency of electron transport by PSI. This was observed to increase progressively with time. The quantum efficiencies of both photosystems increased in parallel, consistent with a predominant role for noncyclic electron transport. Fructose-1,6-bisphosphatase activity increased in an approximately sigmoidal fashion with time of irradiance, paralleling the changes in the quantum efficiencies of the photosystems. In contrast, the activation of NADP-malate dehydrogenase did not show a lag period but increased with time, reaching a maximum value at about 50 seconds of illumination, after which it declined. The NADP pool was not extensively reduced during the first 10 seconds of illumination, but became so subsequently. It remained in the reduced state until about 60 seconds of illumination and then became relatively oxidized. The empirical relationship between NADPmalate dehydrogenase activity and the reduction state of the NADP pool supports the suggestion that NADP-malate dehydrogenase activity is a useful estimate of the reduction state of the stroma.Precise coordinate regulation of the electron transport processes and carbon assimilation is an essential feature of photosynthesis. Coordinate regulation in vivo acts to reconcile the conflicting requirements of these processes (4,8,9,16). The enzymes of the carbon reduction cycle require adequate levels of ATP and NADPH to drive carbon assimilation, whereas the electron transport system will only operate efficiently if NADP and ADP are plentiful; hence, the dilemma that must be resolved by precise coordinate control (4,8,9).Concepts of coordinate control of the electron transport processes and the carbon reduction cycle have frequently been derived from a knowledge of the discrete regulatory properties of each individual reaction sequence. Only recently has it been acknowledged that in vivo regulation is much more complex and refined than might be expected from in vitro measurements of individual components of the overall process (4, 8). Physiological events may be reproduced in reconstituted systems, but such systems frequently consist of rather unnatural combinations of components at unph...

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Regulation of the formation and utilization of photosynthate in leaves

Cited by 124 publications

References 124 publications

Transport Processes and Corresponding Changes in Metabolite Levels in Relation to Starch Synthesis in Barley (Hordeum vulgare L.) Etioplasts

Transport Processes and Corresponding Changes in Metabolite Levels in Relation to Starch Synthesis in Barley (Hordeum vulgare L.) Etioplasts

Light-regulated expression of the Arabidopsis thaliana ferredoxin A gene involves both transcriptional and post-transcriptional processes

Control of the Quantum Efficiencies of Photosystems I and II, Electron Flow, and Enzyme Activation following Dark-to-Light Transitions in Pea Leaves

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