Function of plastidial pyruvate kinases in seeds of Arabidopsis thaliana†
| Autor: | Sylvie Wuillème, Loïc Lepiniec, Bertrand Dubreucq, Sébastien Baud, Aurélie De Almeida, Cindy Vuagnat, Christine Rochat, Martine Miquel |
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| Rok vydání: | 2007 |
| Předmět: |
2. Zero hunger
0106 biological sciences chemistry.chemical_classification 0303 health sciences biology Mutant Fatty acid Cell Biology Plant Science biology.organism_classification 01 natural sciences 03 medical and health sciences chemistry.chemical_compound Metabolic pathway chemistry Biochemistry Arabidopsis Genetics Arabidopsis thaliana Plastid Pyruvate kinase Fatty acid synthesis 030304 developmental biology 010606 plant biology & botany |
| Zdroj: | The Plant Journal. 52:405-419 |
| ISSN: | 0960-7412 |
| DOI: | 10.1111/j.1365-313x.2007.03232.x |
| Popis: | Pyruvate kinase (PK) catalyses the irreversible synthesis of pyruvate and ATP, which are both used in multiple biochemical pathways. These compounds are essential for sustained fatty acid production in the plastids of maturing Arabidopsis embryos. Using a real-time quantitative reverse transcriptase (RT)-PCR approach, the three genes encoding putative plastidial PKs (PKps) in Arabidopsis, namely PKp1 (At3g22960), PKp2 (At5g52920) and PKp3 (At1g32440), were shown to be ubiquitously expressed. However, only PKp1 and PKp2 exhibited significant expression in maturing seeds. The activity of PKp1 and PKp2 promoters was consistent with this pattern, and the study of the PKp1:GFP and PKp2:GFP fusion proteins confirmed the plastidial localization of these enzymes. To further investigate the function of these two PKp isoforms in seeds comprehensive functional analyses were carried out, including the cytological, biochemical and molecular characterization of two pkp1 and two pkp2 alleles, together with a pkp1pkp2 double mutant. The results obtained outlined the importance of these PKps for fatty acid synthesis and embryo development. Mutant seeds were depleted of oil, their fatty acid content was drastically modified, embryo elongation was retarded and, finally, seed germination was also affected. Together, these results provide interesting insights concerning the carbon fluxes leading to oil synthesis in maturing Arabidopsis seeds. The regulation of this metabolic network by the WRINKLED1 transcription factor is discussed, and emphasizes the role of plastidial metabolism and the importance of its tight regulation. |
| Databáze: | OpenAIRE |
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