Distinct triterpene synthases in the laticifers of Euphorbia lathyris

Abstract Euphorbia lathyris was proposed about fifty years ago as a potential agroenergetic crop. The tremendous amounts of triterpenes present in its latex has driven investigations for transforming this particular biological fluid into an industrial hydrocarbon source. The huge accumulation of terpenes in the latex of many plant species represent a challenging question regarding cellular homeostasis. In fact, the enzymes, the mechanisms and the controllers that tune the amount of products accumulated in specialized compartments (to fulfill ecological roles) or deposited at important sites (as essential factors) are not known. Here, we have isolated oxidosqualene cyclases highly expressed in the latex of Euphorbia lathyris. This triterpene biosynthetic machinery is made of distinct paralogous enzymes responsible for the massive accumulation of steroidal and non-steroidal tetracyclic triterpenes. More than eighty years after the isolation of butyrospermol from shea butter (Heilbronn IM, Moffet GL, and Spring FS J. Chem. Soc. 1934, 1583), a butyrospermol synthase is characterized in this work using yeast and in folia heterologous expression assays

High-throughput sequencing of black pepper root transcriptome

Abstract\ud \ud Background\ud Black pepper (Piper nigrum L.) is one of the most popular spices in the world. It is used in cooking and the preservation of food and even has medicinal properties. Losses in production from disease are a major limitation in the culture of this crop. The major diseases are root rot and foot rot, which are results of root infection by Fusarium solani and Phytophtora capsici, respectively. Understanding the molecular interaction between the pathogens and the host’s root region is important for obtaining resistant cultivars by biotechnological breeding. Genetic and molecular data for this species, though, are limited. In this paper, RNA-Seq technology has been employed, for the first time, to describe the root transcriptome of black pepper.\ud \ud \ud Results\ud The root transcriptome of black pepper was sequenced by the NGS SOLiD platform and assembled using the multiple-k method. Blast2Go and orthoMCL methods were used to annotate 10338 unigenes. The 4472 predicted proteins showed about 52% homology with the Arabidopsis proteome. Two root proteomes identified 615 proteins, which seem to define the plant’s root pattern. Simple-sequence repeats were identified that may be useful in studies of genetic diversity and may have applications in biotechnology and ecology.\ud \ud \ud Conclusions\ud This dataset of 10338 unigenes is crucially important for the biotechnological breeding of black pepper and the ecogenomics of the Magnoliids, a major group of basal angiosperms.FAPESPAUFPAFINEPCAPE

High-throughput sequencing of black pepper root transcriptome

Background: Black pepper (Piper nigrum L.) is one of the most popular spices in the world. It is used in cooking and the preservation of food and even has medicinal properties. Losses in production from disease are a major limitation in the culture of this crop. The major diseases are root rot and foot rot, which are results of root infection by Fusarium solani and Phytophtora capsici, respectively. Understanding the molecular interaction between the pathogens and the host's root region is important for obtaining resistant cultivars by biotechnological breeding. Genetic and molecular data for this species, though, are limited. In this paper, RNA-Seq technology has been employed, for the first time, to describe the root transcriptome of black pepper. Results: The root transcriptome of black pepper was sequenced by the NGS SOLiD platform and assembled using the multiple-k method. Blast2Go and orthoMCL methods were used to annotate 10338 unigenes. The 4472 predicted proteins showed about 52% homology with the Arabidopsis proteome. Two root proteomes identified 615 proteins, which seem to define the plant's root pattern. Simple-sequence repeats were identified that may be useful in studies of genetic diversity and may have applications in biotechnology and ecology. Conclusions: This dataset of 10338 unigenes is crucially important for the biotechnological breeding of black pepper and the ecogenomics of the Magnoliids, a major group of basal angiosperms.Rede Paraense de Genomica e Proteomica (Governo do Estado do Para/SEDECT/FAPESPA)Rede Paraense de Genomica e Proteomica (Governo do Estado do Para/SEDECT/FAPESPA)PROPESP/UFPAPROPESP/UFPAFADESPFADESPFINEPFINEPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CAPES (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior

Ultra-Deep Sequencing Reveals the microRNA Expression Pattern of the Human Stomach

Background: While microRNAs (miRNAs) play important roles in tissue differentiation and in maintaining basal physiology, little is known about the miRNA expression levels in stomach tissue. Alterations in the miRNA profile can lead to cell deregulation, which can induce neoplasia. Methodology/Principal Findings: A small RNA library of stomach tissue was sequenced using high-throughput SOLiD sequencing technology. We obtained 261,274 quality reads with perfect matches to the human miRnome, and 42% of known miRNAs were identified. Digital Gene Expression profiling (DGE) was performed based on read abundance and showed that fifteen miRNAs were highly expressed in gastric tissue. Subsequently, the expression of these miRNAs was validated in 10 healthy individuals by RT-PCR showed a significant correlation of 83.97% (P<0.05). Six miRNAs showed a low variable pattern of expression (miR-29b, miR-29c, miR-19b, miR-31, miR-148a, miR-451) and could be considered part of the expression pattern of the healthy gastric tissue. Conclusions/Significance: This study aimed to validate normal miRNA profiles of human gastric tissue to establish a reference profile for healthy individuals. Determining the regulatory processes acting in the stomach will be important in the fight against gastric cancer, which is the second-leading cause of cancer mortality worldwide.Governo do Para/SEDECT/FAPESPAPROPESP/UFPAFADESPCAPES (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior

Metabolism and Biological Activities of 4-Methyl-Sterols

4,4-Dimethylsterols and 4-methylsterols are sterol biosynthetic intermediates (C4-SBIs) acting as precursors of cholesterol, ergosterol, and phytosterols. Their accumulation caused by genetic lesions or biochemical inhibition causes severe cellular and developmental phenotypes in all organisms. Functional evidence supports their role as meiosis activators or as signaling molecules in mammals or plants. Oxygenated C4-SBIs like 4-carboxysterols act in major biological processes like auxin signaling in plants and immune system development in mammals. It is the purpose of this article to point out important milestones and significant advances in the understanding of the biogenesis and biological activities of C4-SBIs

Biosynthèse des stérols (Biochimie et analyse moléculaire des stérol-4a-méthyl-oxydases de plantes)

Les stérols, vitaux aux eucaryotes supérieurs, ne sont fonctionnels qu'après élimination des méthyles en position C4. La déméthylation en C4 des précurseurs stéroliques est effectuée par un complexe multienzymatique au sein duquel les stérol-4a-méthyl-oxydases (SMO) réalisent la première étape de ce processus. Chez les plantes, deux familles de gènes candidats, SMO1 et SMO2, faisant partie de la famille des oxygénases membranaires à fer non-hémique, ont été isolées in silico. L'expression hétérologue des gènes candidats d'Arabidopsis thaliana dans un mutant de Saccharomyces cerevisiae déficient en SMO, montre que seuls les gènes de la famille SMO2 permettent de rétablir la synthèse d'ergostérol dans celui-ci et sa croissance en absence d'ergostérol dans la milieu. La réduction d'expression des gènes SMO1, chez Nicotiana benthamiana, via la technique de virus-induced gene silencing (VIGS), provoque une accumulation spécifique de 4,4-diméthyl-cyclopropyl-stérols, alors que celle de SMO2 induit une augmentation spécifique de 4a-méthyl-D7-stérols. Les données obtenues ont permis d'identifier et de caractériser fonctionnellement, pour la première fois, deux familles de SMO végétales distinctes, régulant respectivement le taux des précurseurs 4,4-diméthyl- et 4a-méthyl-stérols. Les plantes se distinguent donc nettement des animaux et des levures, qui ne possèdent qu'une seule enzyme catalysant l'oxydation successive des deux méthyles en position 4 des précurseurs 4,4-diméthyl-stérols.Sterols are ubiquitous and essential membrane components of eukaryotic cells. In plants, the conversion of cycloartenol to functional phytosterols requires the removal of two methyl-groups at C4 position by an enzymatic complex including a sterol-4a-methyl-oxidase (SMO). We have identified in silico candidate genes for two distinct families of SMO in Arabidopsis thaliana which belong to the small family of membrane-bound non-heme iron oxygenases involved in lipid oxidation. Heterologous expression of plants AtSMO1 in a yeast mutant lacking SMO activity can restore neither SMO activity nor endogenous ergosterol biosynthesis in contrast to AtSMO2 which can functionally complement this mutant strain. In order to decrease the level of plant SMO expression in Nicotiana benthamiana, we have used a virus-induced gene silencing (VIGS) approach. The silencing of SMO1 genes generates a substantial and specific accumulation of 4,4-dimethyl-cyclopropyl-sterols whereas in SMO2 silenced plants there is an accumulation of 4a-methyl-D7-sterols. These distinct biochemical phenotypes demonstrate that in photosynthetic eukaryotes, contrary to animals and fungi, SMO1 and SMO2 families are respectively controlling the levels of 4,4-dimethyl- and 4a-methylsterol precursors.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF