Overexpression of the triose phosphate translocator (TPT) complements the abnormal metabolism and development of plastidial glycolytic glyceraldehyde‐3‐phosphate dehydrogenase mutants |
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| Authors: | María Flores‐Tornero Armand D Anoman Sara Rosa‐Téllez Walid Toujani Andreas PM Weber Marion Eisenhut Samantha Kurz Saleh Alseekh Alisdair R Fernie Jesús Muñoz‐Bertomeu Roc Ros |
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| Affiliation: | 1. Departament de Biologia Vegetal, Facultat de Farmácia, Universitat de València, Burjassot, Spain;2. Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, 46100 Burjassot, Spain;3. Institut für Biochemie der Pflanzen, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich‐Heine Universit?t, D‐40225, Düsseldorf, Germany;4. Max Planck Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam‐Golm, Germany |
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| Abstract: | The presence of two glycolytic pathways working in parallel in plastids and cytosol has complicated the understanding of this essential process in plant cells, especially the integration of the plastidial pathway into the metabolism of heterotrophic and autotrophic organs. It is assumed that this integration is achieved by transport systems, which exchange glycolytic intermediates across plastidial membranes. However, it is unknown whether plastidial and cytosolic pools of 3‐phosphoglycerate (3‐PGA) can equilibrate in non‐photosynthetic tissues. To resolve this question, we employed Arabidopsis mutants of the plastidial glycolytic isoforms of glyceraldehyde‐3‐phosphate dehydrogenase (GAPCp) that express the triose phosphate translocator (TPT) under the control of the 35S (35S:TPT) or the native GAPCp1 (GAPCp1:TPT) promoters. TPT expression under the control of both promoters complemented the vegetative developmental defects and metabolic disorders of the GAPCp double mutants (gapcp1gapcp2). However, as the 35S is poorly expressed in the tapetum, full vegetative and reproductive complementation of gapcp1gapcp2 was achieved only by transforming this mutant with the GAPCp1:TPT construct. Our results indicate that the main function of GAPCp is to supply 3‐PGA for anabolic pathways in plastids of heterotrophic cells and suggest that the plastidial glycolysis may contribute to fatty acid biosynthesis in seeds. They also suggest a 3‐PGA deficiency in the plastids of gapcp1gapcp2, and that 3‐PGA pools between cytosol and plastid do not equilibrate in heterotrophic cells. |
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| Keywords: |
Arabidopsis thaliana
glyceraldehyde‐3‐phosphate dehydrogenase plastidial glycolysis At1g79530 (GAPCp1) At1g16300 (GAPCp2) At5g46110 (TPT) |
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