Short-term effects of nitrate, nitrite and ammonium assimilation on photosynthesis, carbon partitioning and protein phosphorylation in maize

Foyer, Christine H.; Noctor, Graham; Lelandais, Maud; Lescure, JC; Valadier, Marie‐Hélène; Jp, Boutin; Horton, Peter

doi:10.1007/bf01089037

Cited by 80 publications

(58 citation statements)

References 36 publications

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“…therein) have shown that an increased demand for carbon in the synthesis of glutamate imposed by the addition of NO3+ or NH4+ is met by an equivalent increase in the steady-state conversion of pyruvate to acetyl-COA and C 0 2 and of PEP to oxaloacetate. Results with higher plant systems also indicate that light results in an enhanced conversion of PEP to oxaloacetate, and that this activation could be mediated by a phosphorylation of PEPcase (see Champigny and Foyer, 1992;Foyer et al, 1994). Superficially, the simultaneous activation of PEPcase and inhibition of PDC by light is a contradiction that should not have happened in the course of evolution.…”

Section: Llmltatlons O N Noa-reduction the Carbon Supplymentioning

confidence: 99%

Efficiency of Nitrogen Utilization in C3 and C4 Cereals

Oaks¹

1994

Plant Physiol.

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Addition of nitrogen leads to increased dry matter accumulation in vegetative plant parts and to increased final yields in cereal crops (Hageman and Lambert, 1988). The efficiency with which nitrogen is used varies with plant species and with environmental conditions. For example, plants that possess a C4 pattem of photosynthesis have, in addition to a superior method for trapping COz from the atmosphere, a greater nitrogen use efficiency (g dry matter gain per mg nitrogen utilized) than do C3 plants (Brown, 1978). Although there are many differences in the metabolism of C3 and C4 plants, the major difference between these two pattems of photosynthesis is the contribution of photorespiration to both carbon and nitrogen metabolism. When photorespiration is reduced in C3 plants either by increasing ambient levels of COz or reducing levels of 02, both the yield (vegetative dry matter) and nitrogen use efficiency are enhanced (Evans, 1989). As indicated in Table I, this effect is apparent in wheat, a C3 cereal, but not in maize, a C4 cereal (Hocking and Meyer, 1991).Factors that could be altered by reducing the contribution of photorespiration are the carbon supply necessary to drive the net increase in carbohydrate and protein and the availability of reductant and ATP. In this article I demonstrate that high levels of NO3-seen in barley and wheat relative to maize and sorghum (Martin et al., 1983) are related to a carbon deficiency caused by the inhibition of the mitochondrial PDC by monovalent cations, in particular by the NH4+ produced by photorespiration in C3 plants (Schuller and Randall, 1989; Gemel and Randall, 1992). NH4+ production is lower in C4 than in C3 cereals (Martin et al., 1983). In addition, since NH4+ production is localized in bundle sheath cells in C4 plants, whereas NO3-assimilation is found in mesophyll cells (Edwards, 1986; Becker et al., 1993), its impact on the carbon flow required for NO3-assimilation should be negligible in C4 plants.

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Section: Llmltatlons O N Noa-reduction the Carbon Supplymentioning

confidence: 99%

Efficiency of Nitrogen Utilization in C3 and C4 Cereals

Oaks¹

1994

Plant Physiol.

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“…Along these lines, it has been suggested recently that Gln and Glu are positive a n d negative regulatory effectors of C, PEPCkinase, respectively (Manh et al, 1993), a n d that a n increase in endogenous Gln could lead to the reciproca1 modulation of SPS and PEPC activity by changes in phosphorylation state (Foyer et al, 1994). Vanlerberghe et al (1990) reported that Gln and Glu play a key role in regulating PEPC activity in a green alga, but this may simply be due to an allosteric effect on the enzyme (Schuller et al, 1990a).…”

Section: Dlscusslonmentioning

confidence: 99%

In Vivo Regulation of Wheat-Leaf Phosphoenolpyruvate Carboxylase by Reversible Phosphorylation

Duff¹,

Chollet²

1995

Plant Physiol.

116

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“…There has been considerable speculation that certain amino acids, most notably Gin, may act as second messengers in modulating C 3 and C 4 leaf PEPC phosphorylation by PEPC-PK in N-deficient seedlings (Manh et al, 1993;Foyer et al, 1994;Champigny, 1995). Given the fact that PEPC gene expression also is greatly influenced by N status and the level of Gin in these leaves (Sugiharto et al, 1992;Manh et al, 1993), it is not certain whether the changes in PEPC activity observed in the former studies resulted from changes in its phosphorylation state and / or PEPC-PK activity.…”

Section: Gin Is Involved In the Light Activation Of Tobacco-leaf Pepcmentioning

confidence: 99%

Phosphoenolpyruvate Carboxylase Kinase in Tobacco Leaves Is Activated by Light in a Similar but Not Identical Way as in Maize

Zhang

Chollet

1996

Plant Physiology

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We have previously reported the partial purification of a Ca2+- independent phosphoenolpyruvate carboxylase (PEPC) protein-serine/threonine kinase (PEPC-PK) from illuminated leaves of N-sufficient tobacco (Nicotiana tabacum L.) plants (Y.-H. Wang, R. Chollet [1993] FEBS Lett 328: 215–218). We now report that this C3 PEPC-kinase is reversibly light activated in vivo in a time-dependent manner. As the kinase becomes light activated, the activity and L-malate sensitivity of its target protein increases and decreases, respectively. The light activation of tobacco PEPC-PK is prevented by pretreatment of detached leaves with various photosynthesis and cytosolic protein-synthesis inhibitors. Similarly, specific inhibitors of glutamine synthetase block the light activation of tobacco leaf PEPC-kinase under both photorespiratory and nonphotorespiratory conditions. This striking effect is partially and specifically reversed by exogenous glutamine, whereas it has no apparent effect on the light activation of the maize (Zea mays L.) leaf kinase. Using an in situ “activity-gel” phosphorylation assay, we have identified two major Ca2+-independent PEPC-kinase catalytic polypeptides in illuminated tobacco leaves that have the same molecular masses (approximately 30 and 37 kD) as found in illuminated maize leaves. Collectively, these results indicate that the phosphorylation of PEPC in N-sufficient leaves of tobacco (C3) and maize (C4) is regulated through similar but not identical light-signal transduction pathways.

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Short-term effects of nitrate, nitrite and ammonium assimilation on photosynthesis, carbon partitioning and protein phosphorylation in maize

Cited by 80 publications

References 36 publications

Efficiency of Nitrogen Utilization in C3 and C4 Cereals

Efficiency of Nitrogen Utilization in C3 and C4 Cereals

In Vivo Regulation of Wheat-Leaf Phosphoenolpyruvate Carboxylase by Reversible Phosphorylation

Phosphoenolpyruvate Carboxylase Kinase in Tobacco Leaves Is Activated by Light in a Similar but Not Identical Way as in Maize

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