An integrated bioinformatics analysis reveals divergent evolutionary pattern of oil biosynthesis in high- and low-oil plants

Seed oils provide a renewable source of food, biofuel and industrial raw materials that is important for humans. Although many genes and pathways for acyl-lipid metabolism have been identified, little is known about whether there is a specific mechanism for high-oil content in high-oil plants. Based on the distinct differences in seed oil content between four high-oil dicots (20~50%) and three low-oil grasses (<3%), comparative genome, transcriptome and differential expression analyses were used to investigate this mechanism. Among 4,051 dicot-specific soybean genes identified from 252,443 genes in the seven species, 54 genes were shown to directly participate in acyl-lipid metabolism, and 93 genes were found to be associated with acyl-lipid metabolism. Among the 93 dicot-specific genes, 42 and 27 genes, including CBM20-like SBDs and GPT2, participate in carbohydrate degradation and transport, respectively. 40 genes highly up-regulated during seed oil rapid accumulation period are mainly involved in initial fatty acid synthesis, triacylglyceride assembly and oil-body formation, for example, ACCase, PP, DGAT1, PDAT1, OLEs and STEROs, which were also found to be differentially expressed between high- and low-oil soybean accessions. Phylogenetic analysis revealed distinct differences of oleosin in patterns of gene duplication and loss between high-oil dicots and low-oil grasses. In addition, seed-specific GmGRF5, ABI5 and GmTZF4 were predicted to be candidate regulators in seed oil accumulation. This study facilitates future research on lipid biosynthesis and potential genetic improvement of seed oil content

Identification and characterization of DGA2, an acyltransferase of the DGAT1 acyl-CoA:diacylglycerol acyltransferase family in the oleaginous yeast Yarrowia lipolytica. New insights into the storage lipid metabolism of oleaginous yeasts

Triacylglycerols (TAG) and steryl esters (SE) are the principal storage lipids in all eukaryotic cells. In yeasts, these storage lipids accumulate within special organelles known as lipid bodies (LB). In the lipid accumulation-oriented metabolism of the oleaginous yeast Yarrowia lipolytica, storage lipids are mostly found in the form of TAG, and only small amounts of SE accumulate. We report here the identification of a new DAG acyltransferase gene, DGA2, homologous to the ARE genes of Saccharomyces cerevisiae. This gene encodes a member of the type 1 acyl-CoA:diacylglycerol acyltransferase family (DGAT1), which has not previously been identified in yeasts, but is commonly found in mammals and plants. Unlike the Are proteins in S. cerevisiae, Dga2p makes a major contribution to TAG synthesis via an acyl-CoA-dependent mechanism and is not involved in SE synthesis. This enzyme appears to affect the size and morphology of LB, suggesting a direct role of storage lipid proteins in LB formation. We report that the Are1p of Y. lipolytica was essential for sterol esterification, as deletion of the encoding gene (ARE1) completely abolished SE synthesis. Unlike its homologs in yeasts, YlARE1 has no DAG acyltransferase activity. We also reconsider the role and function of all four acyltransferase enzymes involved in the final step of neutral lipid synthesis in this oleaginous yeast

Diversité des agricultures – le cas des filières céréales, oléagineux et légumineuses à graines

L’objectif de cet article est de décrire, sans être exhaustif, la diversité des agricultures en mobilisant des exemples au niveau du système technique et des pratiques culturales, pour la France métropolitaine et pour trois filières : les céréales, les oléagineux et les légumineuses à graines. L’analyse de la diversité des agricultures montre que des voies de diversification des systèmes techniques et des pratiques culturales existent, mais que celles-ci sont fortement dépendantes de la diversité des voies de valorisation dans les filières. Au sein de ces dispositifs de valorisation, hormis quelques dispositifs spécifiques, les recommandations sur les pratiques sont suffisamment vastes pour permettre une diversité de systèmes de culture et de production, dès lors que les critères technologiques d’accès à la filière sont atteints. Il convient alors de s’interroger sur le poids de ces critères technologiques sur les choix techniques des agriculteurs. Il apparait également nécessaire de questionner la valeur donnée à la diversité par les différents acteurs des filières, de l’agriculteur au consommateur, en évaluant notamment la performance économique des systèmes agricoles les plus diversifiés ainsi que les leviers pour augmenter les performances d’une agriculture diversifiée. Il s’agit d’élargir le socle de connaissances sur lequel les acteurs pourront concevoir eux-mêmes de nouvelles formes de diversité et d’ouvrir le débat avec les acteurs des filières sur la préservation des formes de diversité des agricultures comme potentiel de résilience

A comparison of natural and induced diversity in plant oils

Currently, there is a growing demand to replace the compounds in a given product that are of a petroleum origin with renewable resources. One of these compounds, called fatty acid (FA), is the main component of vegetable oils. FA composition is not only responsible for the physicochemical properties of plant oils, but it also determines their uses. For example, since time immemorial, products containing lipids have been used for lighting and heating purposes. They are also excellent lubricants and possess drying properties important molecules for painting, and wood preservation. In terms of nutrition, they have a high-energy content, are part of our daily health requirements, and are used for animal feed. We present here some lipids of interest, the plants that produce them naturally with high yield, the enzymes responsible for their synthesis when known, and their possible uses, as well as resources and ways that could allow the lipids of interest to be produced in quantity in different hosts

Premier thème : Effet de la température et de différents sels sur la stabilité de la phosphoglycerate kinase du muscle de cheval. Deuxième thème : Photorégulation du cycle de Benson-Calvin au niveau des phosphatases : étude de deux formes activées de la fructose-1,6-bisphosphatase de Spinacia oleracea. Régulation de la phosphoenolpyruvatecarboxylase (PEPC) de Crassula argentea et de Zea mays. Troisième thème : Modification de protéines d'intérêt agro-alimentaire par des protéines kinases et des protéines phosphatases

* INRA Paris-Grignon (FRA) Diffusion du document : INRA Paris-Grignon (FRA) Diplôme : Dr. d'Universit

Premier thème : Effet de la température et de différents sels sur la stabilité de la phosphoglycerate kinase du muscle de cheval. Deuxième thème : Photorégulation du cycle de Benson-Calvin au niveau des phosphatases : étude de deux formes activées de la fructose-1,6-bisphosphatase de Spinacia oleracea. Régulation de la phosphoenolpyruvatecarboxylase (PEPC) de Crassula argentea et de Zea mays. Troisième thème : Modification de protéines d'intérêt agro-alimentaire par des protéines kinases et des protéines phosphatases

* INRA Paris-Grignon (FRA) Diffusion du document : INRA Paris-Grignon (FRA) Diplôme : Dr. d'Universit

Le calcium et le fructose-1- 6-biphosphate activent la fructose-1- 6-biphosphatase

National audienc

Etude des proprietes cinetiques et structurales de la fructose-1- 6-biphosphatase de chloroplaste d'epinard activee par le calcium et le fructose-16-biphosphate

National audienc

Fructose-1,6-biphosphate and calcium activate spinach (Spinacia oleracea) chloroplast fructose-1-6-biphosphatase

International audienc