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Recherche d'enzymes impliquées dans la voie de biosynthèse de la carnitine chez Arabidopsis thaliana et étude préliminaire de mutants à teneur réduite en carnitine

Abstract : Carnitine, a crucial amino acid for the intacellular transfer of fatty acids in animals and microorganisms, is present in plants but its mode of implication in lipid metabolism and development remains to be determined. In order to investigate the biological function of carnitine in Arabidopsis, we initiated a bioinformatic search for enzymes that could be involved in its synthesis in order to obtain mutants with a reduced carnitine content. Serine hydroxymethyl transferases (SHMT), threonine aldolase (THA) and aldehyde dehydrogenase (ALDH) were identified as candidates. A search for mutants, either characterized or in available collections ans an amiRNA mutagenesis approach were carried out. In these mutants, the y-butyrobetaine as carnitine precursor, the carnitine, and carnitine esters were quantified. The THA enzymes do not appear to be involved in the carnitine synthesis and even if a weak mutant of SHMT1 has reduced contents of carnitine and y-butyrobetaine, the involvement of this protein remains to be demonstrated. A study of a knock-out mutant of the ALDH10A8 gene, of knock-down mutants of ALDH10A9 and a functional complementation of a C. albicans ALDH mutant, has confirmed the implication of ALDH10A8 and ALDH10A9 enzymes in the synthesis of y-butyrobetaine within the cartinine biosynthesis pathway. Mutants of the ALDH10 proteins, having significantly reduced carnitine and acyl-carnitine amounts, are now available as tools for studying the role of carnitine in Arabidopsis.
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https://tel.archives-ouvertes.fr/tel-01077965
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Submitted on : Monday, October 27, 2014 - 2:55:57 PM
Last modification on : Monday, April 19, 2021 - 8:52:32 AM
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Yingjuan Zhao. Recherche d'enzymes impliquées dans la voie de biosynthèse de la carnitine chez Arabidopsis thaliana et étude préliminaire de mutants à teneur réduite en carnitine. Biotechnologies. Université de Technologie de Compiègne, 2014. Français. ⟨NNT : 2014COMP2136⟩. ⟨tel-01077965⟩

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