Metabolic Adaptations of Plant Respiration to Nutritional Phosphate Deprivation

Theodorou, Maria E.; Plaxton, William C.

doi:10.1104/pp.101.2.339

Cited by 335 publications

(222 citation statements)

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“…The activities of the PEPc reaction can lead to the synthesis of malate via MDH (Duff et al, 1989;Plaxton, 1996) and although malate is a known inhibitor of PEPc activity (Schuller & Werner, 1993), there was no consistent relationship between malate concentration and the inhibition of in vitro PEPc activity. Instead, our in vitro PEPc activity varied with the P levels, as proposed by previous studies (Duff et al, 1989;Theodorou & Plaxton, 1993;Juszczuk & Rychter, 2002).…”

Section: Discussionsupporting

confidence: 58%

Routes of pyruvate synthesis in phosphorus‐deficient lupin roots and nodules

et al. 2005

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Summary• Here, nodulated lupins ( Lupinus angustifolius (cv Wonga)) were hydroponically grown at low phosphate (LP) or adequate phosphate (HP).• Routes of pyruvate synthesis were assessed in phosphorus (P)-starved roots and nodules, because P-starvation can enhance metabolism of phospho enol pyruvate (PEP) via the nonadenylate-requiring PEP carboxylase (PEPc) route. Since nodules and roots may not experience the same degree of P stress, it was postulated that decreases in metabolic inorganic phosphorus (P i ) of either organ, should favour more pyruvate being synthesized from PEPc-derived malate.• Compared with HP roots, the LP roots had a 50% decline in P i concentrations and 55% higher ADP : ATP ratios. However, LP nodules maintained constant P i levels and unchanged ADP : ATP ratios, relative to HP nodules. The LP roots had greater PEP metabolism via PEPc and synthesized more pyruvate from PEPc-derived malate. In nodules, P supply did not influence PEPc activities or levels of malate-derived pyruvate.• These results indicate that nodules were more efficient than roots in maintaining optimal metabolic P i and adenylate levels during LP supply. This caused an increase in PEPc-derived pyruvate synthesis in LP roots, but not in LP nodules.

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Section: Discussionsupporting

confidence: 58%

Routes of pyruvate synthesis in phosphorus‐deficient lupin roots and nodules

et al. 2005

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“…Concomitant with an increase in PPDK activity, low-oxygen stress induced an increase in PEPC and total MDH activities in roots and etiolated rice seedlings (Figure 6b). A PEPC mediated CO 2 -fixation is known to be part of the metabolic response of plants during phosphorous deficiency, which also affects the energy-metabolism (Theodorou and Plaxton, 1993). Cytosolic PPDK has also been proposed to be involved in amino acid interconversions in seeds (Aoyagi and Bassham, 1984) and the recycling of coenzymes, which could be linked to the accumulation of proline in rice roots during low-oxygen stress (Bertani and Reggiani, 1991).…”

Section: Discussionmentioning

confidence: 99%

Low‐oxygen stress and water deficit induce cytosolic pyruvate orthophosphate dikinase (PPDK) expression in roots of rice, a C₃ plant

et al. 1998

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SummaryPyruvate orthophosphate dikinase (PPDK) is known for its role in C 4 photosynthesis but has no established function in C 3 plants. Abscisic acid, PEG and submergence were found to markedly induce a protein of about 97 kDa, identified by microsequencing as PPDK, in rice roots (C 3 ). The rice genome was found to contain two ppdk loci, osppdka and osppdkb. We isolated osppdka cDNA, which encodes a cytosolic rice PPDK isoform of 96.6 kDa, that corresponded to the ABA-induced protein from roots. Western blot analysis showed a PPDK induction in roots of rice seedlings during gradual drying, cold, high salt and mannitol treatment, indicating a water deficit response. PPDK was also induced in the roots and sheath of submerged rice seedlings, and in etiolated rice seedlings exposed to an oxygen-free N 2 atmosphere, which indicated a low-oxygen stress response. None of the stress treatments induced PPDK protein accumulation in the lamina of green rice seedlings. Ppdk transcripts were found to accumulate in roots of submerged seedlings, concomitant with the induction of alcohol dehydrogenase 1. Lowoxygen stress triggered an increase in PPDK activity in roots and etiolated rice seedlings, accompanied by increases in phosphoenolpyruvate carboxylase and malate dehydrogenase activities. The results indicate that cytosolic PPDK is involved in a metabolic response to water deficit and low-oxygen stress in rice, an anoxia-tolerant species.

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“…The alternative pathway has been proposed to operate as a bypass of the ADP-and Pi-controlled cytochrome pathway during phosphorus limitation (Theodorou & Plaxton 1993;Parsons et al 1999). Phosphorus deprivation is known to induce phosphorus-and adenylate-independent enzymes in the cytosol, bypassing major control points of glycolysis and allowing carbon metabolism to continue (Duff et al 1989;Plaxton 1996;Plaxton & Carswell 1999).…”

Section: Metabolic Regulation Of Respiration 211mentioning

confidence: 99%

“…Phosphorus limitation also induces metabolic adaptations in plants that can bypass the adenylate-and phosphate-dependent reactions of glycolysis and respiration (Duff et al 1989;Rychter & Mikulska 1990;Theodorou et al 1991;Hoefnagel, van Iren & Libbenga 1993;Theodorou & Plaxton 1993;Plaxton & Carswell 1999), including the cytochrome pathway. The alternative pathway can act as such a bypass of phosphate control on electron transport (Theodorou & Plaxton 1993). Moreover, restriction of the cytochrome pathway by phosphate deficiency could result in over-reduction of the ubiquinone (UQ)-pool if the alternative oxidase is not active, generating harmful reactive oxygen species (Wagner & Moore 1997;.…”

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confidence: 99%

Metabolic regulation of leaf respiration and alternative pathway activity in response to phosphate supply

et al. 2001

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In this study the question whether the alternative respiratory pathway acts as an electron bypass for the cytochrome pathway under conditions of growth on limited phosphorus in leaves of bean (Phaseolus vulgaris L.), tobacco (Nicotiana tabacum L.) and Gliricidia sepium Walp was investigated. The oxygen isotope fractionation technique was used to assess the in vivo activities of the cytochrome and alternative respiratory pathways in the absence of added inhibitors. The response of respiration to low phosphorus supply varied among species. Growth at low phosphorus reduced cytochrome pathway activity in bean and tobacco. Alternative pathway activity increased only in bean leaves in response to low phosphorus and not in tobacco. In the case of G. sepium, cytochrome pathway activity remained unchanged whereas the alternative pathway activity increased with low nutritional phosphorus. At low phosphorus, alternative oxidase protein levels increased in the leaves of bean and G. sepium but not in tobacco, suggesting a dependence of alternative pathway activity on protein level. Alternative pathway activity was also not correlated with soluble carbohydrate concentration in bean or tobacco at any phosphorus level. These results show that the alternative pathway does not always act as an electron bypass in response to the downstream restriction of the cytochrome pathway imposed by low phosphorus supply. These results suggest that factors in addition to cellular carbohydrate level and adenylate control can act to regulate alternative pathway activity.

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Metabolic Adaptations of Plant Respiration to Nutritional Phosphate Deprivation

Cited by 335 publications

References 19 publications

Routes of pyruvate synthesis in phosphorus‐deficient lupin roots and nodules

Routes of pyruvate synthesis in phosphorus‐deficient lupin roots and nodules

Low‐oxygen stress and water deficit induce cytosolic pyruvate orthophosphate dikinase (PPDK) expression in roots of rice, a C₃ plant

Metabolic regulation of leaf respiration and alternative pathway activity in response to phosphate supply

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Metabolic Adaptations of Plant Respiration to Nutritional Phosphate Deprivation

Cited by 335 publications

References 19 publications

Routes of pyruvate synthesis in phosphorus‐deficient lupin roots and nodules

Routes of pyruvate synthesis in phosphorus‐deficient lupin roots and nodules

Low‐oxygen stress and water deficit induce cytosolic pyruvate orthophosphate dikinase (PPDK) expression in roots of rice, a C3 plant

Metabolic regulation of leaf respiration and alternative pathway activity in response to phosphate supply

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Low‐oxygen stress and water deficit induce cytosolic pyruvate orthophosphate dikinase (PPDK) expression in roots of rice, a C₃ plant