| Metabolism of organic acids, nitrogen and amino acids in chlorotic leaves of 'Honeycrisp' apple (Malus domestica Borkh) with excessive accumulation of carbohydrates. | |
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MedLine Citation:
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PMID: 20490541 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Metabolite profiles and activities of key enzymes in the metabolism of organic acids, nitrogen and amino acids were compared between chlorotic leaves and normal leaves of 'Honeycrisp' apple to understand how accumulation of non-structural carbohydrates affects the metabolism of organic acids, nitrogen and amino acids. Excessive accumulation of non-structural carbohydrates and much lower CO(2) assimilation were found in chlorotic leaves than in normal leaves, confirming feedback inhibition of photosynthesis in chlorotic leaves. Dark respiration and activities of several key enzymes in glycolysis and tricarboxylic acid (TCA) cycle, ATP-phosphofructokinase, pyruvate kinase, citrate synthase, aconitase and isocitrate dehydrogenase were significantly higher in chlorotic leaves than in normal leaves. However, concentrations of most organic acids including phosphoenolpyruvate (PEP), pyruvate, oxaloacetate, 2-oxoglutarate, malate and fumarate, and activities of key enzymes involved in the anapleurotic pathway including PEP carboxylase, NAD-malate dehydrogenase and NAD-malic enzyme were significantly lower in chlorotic leaves than in normal leaves. Concentrations of soluble proteins and most free amino acids were significantly lower in chlorotic leaves than in normal leaves. Activities of key enzymes in nitrogen assimilation and amino acid synthesis, including nitrate reductase, glutamine synthetase, ferredoxin and NADH-dependent glutamate synthase, and glutamate pyruvate transaminase were significantly lower in chlorotic leaves than in normal leaves. It was concluded that, in response to excessive accumulation of non-structural carbohydrates, glycolysis and TCA cycle were up-regulated to "consume" the excess carbon available, whereas the anapleurotic pathway, nitrogen assimilation and amino acid synthesis were down-regulated to reduce the overall rate of amino acid and protein synthesis. |
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Authors:
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Huicong Wang; Fangfang Ma; Lailiang Cheng |
Publication Detail:
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Type: Journal Article Date: 2010-05-20 |
Journal Detail:
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Title: Planta Volume: 232 ISSN: 1432-2048 ISO Abbreviation: Planta Publication Date: 2010 Jul |
Date Detail:
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Created Date: 2010-06-16 Completed Date: 2010-09-09 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 1250576 Medline TA: Planta Country: Germany |
Other Details:
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Languages: eng Pagination: 511-22 Citation Subset: IM |
Affiliation:
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Department of Horticulture, Cornell University, Ithaca, NY 14853, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acids
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metabolism* Amino Acids / metabolism* Carbohydrate Metabolism / physiology Carbon Dioxide / metabolism Malus / enzymology, metabolism* Nitrogen / metabolism* Plant Diseases* Plant Leaves / enzymology, metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Acids; 0/Amino Acids; 124-38-9/Carbon Dioxide; 7727-37-9/Nitrogen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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