Chapter New Opportunities in Metabolomics and Biochemical Phenotyping for Plant Systems Biology

Pollution contro

New Opportunities in Metabolomics and Biochemical Phenotyping for Plant Systems Biology

Pollution contro

Phenotypic and fine genetic characterization of the D locus controlling fruit acidity in peach

<p>Abstract</p> <p>Background</p> <p>Acidity is an essential component of the organoleptic quality of fleshy fruits. However, in these fruits, the physiological and molecular mechanisms that control fruit acidity remain unclear. In peach the <it>D </it>locus controls fruit acidity; low-acidity is determined by the dominant allele. Using a peach progeny of 208 F₂trees, the <it>D </it>locus was mapped to the proximal end of linkage group 5 and co-localized with major QTLs involved in the control of fruit pH, titratable acidity and organic acid concentration and small QTLs for sugar concentration. To investigate the molecular basis of fruit acidity in peach we initiated the map-based cloning of the <it>D </it>locus.</p> <p>Results</p> <p>In order to generate a high-resolution linkage map in the vicinity of the <it>D </it>locus, 1,024 AFLP primer combinations were screened using DNA of bulked acid and low-acid segregants. We also screened a segregating population of 1,718 individuals for chromosomal recombination events linked to the <it>D </it>locus and identified 308 individuals with recombination events close to <it>D</it>. Using these recombinant individuals we delimited the <it>D </it>locus to a genetic interval of 0.4 cM. We also constructed a peach BAC library of 52,000 clones with a mean insert size of 90 kb. The screening of the BAC library with markers tightly linked to <it>D </it>locus indicated that 1 cM corresponds to 250 kb at the vicinity of the <it>D </it>locus.</p> <p>Conclusion</p> <p>In the present work we presented the first high-resolution genetic map of <it>D </it>locus in peach. We also constructed a peach BAC library of approximately 15�� genome equivalent. This fine genetic and physical characterization of the <it>D </it>locus is the first step towards the isolation of the gene(s) underlying fruit acidity in peach.</p

Correlation Network Analysis reveals a sequential reorganization of metabolic and transcriptional states during germination and gene-metabolite relationships in developing seedlings of Arabidopsis

<p>Abstract</p> <p>Background</p> <p>Holistic profiling and systems biology studies of nutrient availability are providing more and more insight into the mechanisms by which gene expression responds to diverse nutrients and metabolites. Less is known about the mechanisms by which gene expression is affected by endogenous metabolites, which can change dramatically during development. Multivariate statistics and correlation network analysis approaches were applied to non-targeted profiling data to investigate transcriptional and metabolic states and to identify metabolites potentially influencing gene expression during the heterotrophic to autotrophic transition of seedling establishment.</p> <p>Results</p> <p>Microarray-based transcript profiles were obtained from extracts of Arabidopsis seeds or seedlings harvested from imbibition to eight days-old. ¹H-NMR metabolite profiles were obtained for corresponding samples. Analysis of transcript data revealed high differential gene expression through seedling emergence followed by a period of less change. Differential gene expression increased gradually to day 8, and showed two days, 5 and 7, with a very high proportion of up-regulated genes, including transcription factor/signaling genes. Network cartography using spring embedding revealed two primary clusters of highly correlated metabolites, which appear to reflect temporally distinct metabolic states. Principle Component Analyses of both sets of profiling data produced a chronological spread of time points, which would be expected of a developmental series. The network cartography of the transcript data produced two distinct clusters comprising days 0 to 2 and days 3 to 8, whereas the corresponding analysis of metabolite data revealed a shift of day 2 into the day 3 to 8 group. A metabolite and transcript pair-wise correlation analysis encompassing all time points gave a set of 237 highly significant correlations. Of 129 genes correlated to sucrose, 44 of them were known to be sucrose responsive including a number of transcription factors.</p> <p>Conclusions</p> <p>Microarray analysis during germination and establishment revealed major transitions in transcriptional activity at time points potentially associated with developmental transitions. Network cartography using spring-embedding indicate that a shift in the state of nutritionally important metabolites precedes a major shift in the transcriptional state going from germination to seedling emergence. Pair-wise linear correlations of transcript and metabolite levels identified many genes known to be influenced by metabolites, and provided other targets to investigate metabolite regulation of gene expression during seedling establishment.</p

MeRy-B: a web knowledgebase for the storage, visualization, analysis and annotation of plant NMR metabolomic profiles

<p>Abstract</p> <p>Background</p> <p>Improvements in the techniques for metabolomics analyses and growing interest in metabolomic approaches are resulting in the generation of increasing numbers of metabolomic profiles. Platforms are required for profile management, as a function of experimental design, and for metabolite identification, to facilitate the mining of the corresponding data. Various databases have been created, including organism-specific knowledgebases and analytical technique-specific spectral databases. However, there is currently no platform meeting the requirements for both profile management and metabolite identification for nuclear magnetic resonance (NMR) experiments.</p> <p>Description</p> <p>MeRy-B, the first platform for plant ¹H-NMR metabolomic profiles, is designed (<it>i</it>) to provide a knowledgebase of curated plant profiles and metabolites obtained by NMR, together with the corresponding experimental and analytical metadata, (<it>ii</it>) for queries and visualization of the data, (<it>iii</it>) to discriminate between profiles with spectrum visualization tools and statistical analysis, (<it>iv</it>) to facilitate compound identification. It contains lists of plant metabolites and unknown compounds, with information about experimental conditions, the factors studied and metabolite concentrations for several plant species, compiled from more than one thousand annotated NMR profiles for various organs or tissues.</p> <p>Conclusion</p> <p>MeRy-B manages all the data generated by NMR-based plant metabolomics experiments, from description of the biological source to identification of the metabolites and determinations of their concentrations. It is the first database allowing the display and overlay of NMR metabolomic profiles selected through queries on data or metadata. MeRy-B is available from <url>http://www.cbib.u-bordeaux2.fr/MERYB/index.php</url>.</p

1H-NMR metabolomics: Profiling method for a rapid and efficient screening of transgenic plants

Metabolomics-based approaches are methods of choice for studying changes in fruit composition induced by  environmental or genetic modulation of biochemical pathways in the fruit. Owing to enzyme redundancy and  high plasticity of the metabolic network, transgenic alteration of the activity of the enzymes from the central metabolism very often results in only slight modifications of the fruit composition. In order to avoid costly and  time-consuming plant analysis, we used a fast and sensitive 1H-NMR-based metabolomic profiling technique  allowing discovery of slight metabolite variations in a large number of samples. Here, we describe the  screening of transgenic tomato plants in which two genes from the central metabolism, phosphoenolpyruvate  carboxylase (EC.3.4.1.1) and malate synthase (EC 2.3.3.9) were silenced by antisens and RNAi strategy.  1H-NMR metabolomic profiles of methanol-d4 D2O buffer extracts of tomato fruit flesh were acquired and  subjected to unsupervised multivariate statistical analysis. 1H-NMR spectra were binned into variable-size  spectral domains, making it possible to get an overall analysis of a large number of resonances, even in the  case of uncontrolled variation of the chemical shift. Principal component analysis was used to separate groups  of samples and to relate known and unknown metabolites to transgenic events. The screening of 100 samples,  from extraction to data mining, took 36 h. Thus, this procedure allows the rapid selection of metabolic  phenotypes of interest among about 30 transgenic lines.Key words: Metabolome, GMO, tomato, fruit, 1H-NMR profiling, screening

An inter-laboratory comparison demonstrates that [1H]-NMR metabolite fingerprinting is a robust technique for collaborative plant metabolomic data collection

In any metabolomics experiment, robustness and reproducibility of data collection is of vital importance. These become more important in collaborative studies where data is to be collected on multiple instruments. With minimisation of variance in sample preparation and instrument performance it is possible to elucidate even subtle differences in metabolite fingerprints due to genotype or biological treatment. In this paper we report on an inter laboratory comparison of plant derived samples by [1H]-NMR spectroscopy across five different sites and within those sites utilising instruments with different probes and magnetic field strengths of 9.4 T (400 MHz), 11.7 T (500 MHz) and 14.1 T (600 MHz). Whilst the focus of the study is on consistent data collection across laboratories, aspects of sample stability and the requirement for sample rotation within the NMR magnet are also discussed. Comparability of the datasets from participating laboratories was exceptionally good and the data were amenable to comparative analysis by multivariate statistics. Field strength differences can be adjusted for in the data pre-processing and multivariate analysis demonstrating that [1H]-NMR fingerprinting is the ideal technique for large scale plant metabolomics data collection requiring the participation of multiple laboratories

La reconstitution de l'offre dans les opérations de renouvellement urbain de 2000 à 2004

Contexte :Cette démarche fait suite à une première analyse conduite en 2002 - 2003, par le Certu et quatre cete, ayant abouti à l’élaboration d'un ouvrage intitulé : « Renouvellement urbain - Enseignements de 15 opérations de démolition/reconstruction " . Ce document, destiné aux acteurs du renouvellement urbain et en particulier aux DDE, a souligné la difficulté de reconstituer une offre sociale à l'échelle des agglomérations . Il a également pointé la nécessité d'une meilleure utilisation des PLH pour décliner des politiques de re-développement de l'offre plus équilibrées au sein des Communautés d'Agglomération. C'est pourquoi la DGUHC a souhaité qu'une nouvelle investigation soit réalisée autour de cette double question. Résumé : Au travers des analyses de sites concernant dix agglomérations, l'objectif poursuivi est :- d'analyser la définition, le contenu et la mise en œuvre des politiques de reconstitution de l'offre dans les opérations de renouvellement urbain, à l'échelle de l'agglomération. n - d'apprécier l'articulation entre la reconstitution de l'offre des opérations de renouvellement urbain et les politiques locales de l'habitat. - de favoriser la connaissance des pratiques au regard de la problématique formulée, en premier lieu dans le réseau de l'Équipement, mais aussi auprès des collectivités ou auprès d'autres acteurs du renouvellement urbain. L'étude a été conduite dans un contexte très évolutif en matière de réglementations, de financements et de stratégies institutionnelles avec, d'une part, la création de l'Agence Nationale de la Rénovation Urbaine et, d'autre part, la délégation de compétence aux collectivités locales en matière d'attribution d'aides à la pierre, ouverte par la loi du 13 août 2004 relative aux libertés et responsabilités locales . Elle n'a donc pas vocation à édicter des éléments de doctrine, elle rend compte d'intentions locales, dresse un certain nombre de constats, et tente d'en tirer de premiers enseignements dans le cadre de processus opérationnels, souvent à des stades très amon