PROCÉDÉ DE MODIFICATION DU RAPPORT ATP/ADP DANS DES CELLULES

publication date: 2007-10-25; filing date: 2007-03-20(FR) L'invention concerne un procédé de modification du rapport ATP/ADP dans une cellule, un tissu, un organe, un micro-organisme ou une plante par modification de l'activité d'une protéine à hème dans la cellule. L'invention porte également sur l'application de ce procédé

PROCEDE POUR AMELIORER LA TENEUR GENERALE EN HUILE DANS DES PLANTES OLEAGINEUSES

publication date: 2007-05-10; filing date: 2006-11-06DE) Die Erfindung betrifft Verfahren zur Erhöhung des Gesamtölgehaltes und/oder des Gehalts an Glycerol-3-Phosphat in transgenen Ölpflanzen, die mindestens 20 Gew-% Ölsäure bezogen auf den Gesamtfettsäuregehalt enthalten, bevorzugt in pflanzlichen Samen, durch Expression von Glycerol-3-phosphatdehydrogenasen (G3PDH) aus Hefen, bevorzugt aus Saccharomyces cerevisiae. Vorteilhaft wird das im Verfahren gewonnene Öl und/oder die freien Fettsäure Polymeren, Nahrungsmitteln, Futtermitteln, Kosmetika, Pharmazeutika oder Produkten mit industriellen Anwendungen zugesetzt

Cloning and functional characterisation of an enzyme involved in the elongation of D6-polyunsaturated fatty acids from the moss Physcomitrella patens

The moss Physcomitrella patens contains high proportions of polyunsaturated very-long-chain fatty acids with up to 20 carbon atoms. Starting from preformed C18 polyunsaturated fatty acids, their biosynthesis involves a sequence of Delta6-desaturation, Delta6-elongation and Delta5-desaturation. In this report we describe for the first time the characterisation of a cDNA (PSE1) of plant origin with homology to the ELO-genes from Saccharomyces cerevisiae, encoding a component of the Delta6-elongase. Functional expression of PSE1 in S. cerevisiae led to the elongation of exogenously supplied Delta6-polyunsaturated fatty acids. By feeding experiments with different trienoic fatty acids of natural and synthetic origin, both substrate specificity and substrate selectivity of the enzyme were investigated. The activity of Pse1, when expressed in yeast, was not sensitive to the antibiotic cerulenin, which is an effective inhibitor of fatty acid synthesis and elongation. Furthermore, the PSE1 gene was disrupted in the moss by homologous recombination. This led to a complete loss of all C20 polyunsaturated fatty acids providing additional evidence for the function of the cDNA as coding for a component of the Delta6-elongase. The elimination of the elongase was not accompanied by a visible alteration in the phenotype, indicating that C20-PUFAs are not essential for viability of the moss under phytotron conditions

Increasing seed oil content in oil-seed rape (Brassica napus L.) by over-expression of a yeast glycerol-3-phosphate dehydrogenase under the control of a seed-specific promoter.

Previous attempts to manipulate oil synthesis in plants have mainly concentrated on the genes involved in the biosynthesis and use of fatty acids, neglecting the possible role of glycerol-3-phosphate supply on the rate of triacylglycerol synthesis. In this study, a yeast gene coding for cytosolic glycerol-3-phosphate dehydrogenase (gpd1) was expressed in transgenic oil-seed rape under the control of the seed-specific napin promoter. It was found that a twofold increase in glycerol-3-phosphate dehydrogenase activity led to a three- to fourfold increase in the level of glycerol-3-phosphate in developing seeds, resulting in a 40% increase in the final lipid content of the seed, with the protein content remaining substantially unchanged. This was accompanied by a decrease in the glycolytic intermediate dihydroxyacetone phosphate, the direct precursor of glycerol-3-phosphate dehydrogenase. The levels of sucrose and various metabolites in the pathway from sucrose to fatty acids remained unaltered. The results show that glycerol-3-phosphate supply co-limits oil accumulation in developing seeds. This has important implications for strategies that aim to increase the overall level of oil in commercial oil-seed crops for use as a renewable alternative to petrol