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This research examines the experiences and motivation of high school learners of French who participated in a short student exchange program. For most students, positive family attitudes and experiences in early high school supported motivation, despite a challenging transition when the subject became elective. Anticipation of their exchange allowed students to imagine themselves becoming successful speakers of French, increasing motivation. In France, immersive engagement with host families established connections and enhanced self-confidence. The study suggests that the exchange program was a transformational experience, linking academic ambitions and a desire to travel, and boosting motivation before, during and after the program.

The rose is the queen of flowers and is widely used as a garden plant and for the cut flower market. Roses are also used for the production of essential oil for the cosmetic and perfume industries. A lot of botanical roses are scented and use their volatiles to attract pollinators. Fragrances in garden roses are very diverse and scent has always been an important character in the selection process. Breeders have recently tried to introduce new fragrances, for instance reminiscent of fruit or spice odors. But despite their efforts, some roses on the market are not very fragrant, especially the ones selected for the cut flower market. The cause of this lack of scent is not known. In modern roses or Hybrid Tea roses, scent is mainly produced by petals, although stamens can also contribute to the emission of volatiles. Scent compounds are concentrated in rose petal epidermis, probably in small lipid droplets. In spite of numerous chemical studies, the biosynthetic pathways of many rose scent compounds are unknown. We are studying several genes involved in the biosynthesis of scent in rose. For example, we recently characterized the enzymes responsible for the so-called “tea scent” emitted by Chinese roses. Apart from “tea scent”, terpenoids, especially monoterpenes, are also major constituents of rose flowers, mostly responsible for the “typical rose scent”. Generally, terpenoid biosynthesis in plants is achieved by various terpene synthases. However, with a combination of transcriptomic and genetic approaches, our research group recently discovered a terpene synthase-independent pathway. A key enzyme of this pathway is RhNUDX1, belonging to the Nudix protein family. It has geranyl diphosphate diphosphohydrolase activity in vitro. A positive correlation was found between the expression levels of RhNUDX1 gene and the production of the monoterpene geraniol, indicating its essential role in scent production in roses.

Epub ahead of print; International audience; Roses have high cultural and economic importance as ornamental plants and in the perfume industry. We report the rose whole-genome sequencing and assembly and resequencing of major genotypes that contributed to rose domestication. We generated a homozygous genotype from a heterozygous diploid modern rose progenitor, Rosa chinensis ‘Old Blush’. Using single-molecule real-time sequencing and a meta-assembly approach, we obtained one of the most comprehensive plant genomes to date. Diversity analyses highlighted the mosaic origin of ‘La France’, one of the first hybrids combining the growth vigor of European species and the recurrent blooming of Chinese species. Genomic segments of Chinese ancestry identified new candidate genes for recurrent blooming. Reconstructing regulatory and secondary metabolism pathways allowed us to propose a model of interconnected regulation of scent and flower color. This genome provides a foundation for understanding the mechanisms governing rose traits and should accelerate improvement in roses, Rosaceae and ornamentals.

International audience; Cultivated roses have a very ancient history. Artificial crossing led to what is today perceived as modern rose cultivars. Impressively, these modern rose cultivars were established from less than 10 species, which have contributed to the origin of the about 35,000 existing rose cultivars. Roses exhibit an extraordinary diversity of traits, both of economic and scientific importance. Several recent studies have been marked as important milestones on the journey towards deeply understanding the molecular and genetic mechanisms that govern these traits, yet we still lack information on the genome sequences of rose species and cultivars, especially those that heavily participated to rose domestication and breeding programs.

International audience; Roses hold high symbolic value and great cultural importance in different societies throughout human history. They are widely used as garden ornamental plants, as cut flowers, and for the production of essential oils for the perfume and cosmetic industries. Domestication of roses has a long and complex history, and the rose species have been hybridized across vast geographic areas such as Europe, Asia, and the Middle East. The domestication processes selected several flower characters affecting floral quality, such as recurrent flowering, double flowers, petal colours, and fragrance. The molecular and genetic events that determine some of these flower characters cannot be studied using model species such as Arabidopsis thaliana, or at least only in a limited manner. In this review, we comment on the recent development of genetic, genomic, and transcriptomic tools for roses, and then focus on recent advances that have helped unravel the molecular mechanisms underlying several rose floral traits.

International audience; Phyllody is a flower abnormality in which leaf-like structures replace flower organs in all whorls. Here, we investigated the origin and the molecular mechanism of phyllody phenotype in Rosa chinensis cv. Viridiflora, an ancient naturally occurring Chinese mutant cultivar. Reciprocal grafting experiments and microscopy analyses, demonstrated that the phyllody phenotype in Viridiflora is not associated with phytoplasmas infection. Transcriptome comparisons by the mean of RNA-Seq identified 672 up regulated and 666 down-regulated genes in Viridiflora compared to its closely related genotype R. chinensis cv. Old Blush. A fraction of these genes are putative homologs of genes known to be involved in flower initiation and development. We show that in flower whorl 2 of Viridiflora, a down-regulation of the floral organ identity genes RcPISTILLATA (RcPI), RcAPETALA3 (RcAP3) and RcSEPALLATA3 (RcSEP3), together with an up -regulation of the putative homolog of the gene SUPPRESSOR of OVEREXPRESSION of CONSTANS1 (RcSOC1) are likely at the origin of the loss of petal identity and leaf -like structures formation. In whorl 3 of Viridiflora, ectopic expression of RcAPETALA2 (RcAP2) along with the down regulation of RcPI, RcAP3, and RcSEP3 is associated with loss of stamens identity and leaf -like structures formation. In whorl 4, the ectopic expression of RcAP2 associated with a down -regulation of RcSEP3 and of the C-class gene RcAGAMOUS correlate with loss of pistil identity. The latter also suggested the antagonist effect between the A and C class genes in the rose. Together, these data suggest that modified expression of the ABCE flower organ identity genes is associated with the phyllody phenotype in the rose Viridiflora and that these genes are important for normal flower organs development.

The scent of roses (Rosa x hybrida) is composed of hundreds of volatile molecules. Monoterpenes represent up to 70% percent of the scent content in some cultivars, such as the Papa Meilland rose. Monoterpene biosynthesis in plants relies on plastid-localized terpene synthases. Combining transcriptomic and genetic approaches, we show that the Nudix hydrolase RhNUDX1, localized in the cytoplasm, is part of a pathway for the biosynthesis of free monoterpene alcohols that contribute to fragrance in roses. The RhNUDX1 protein shows geranyl diphosphate diphosphohydrolase activity in vitro and supports geraniol biosynthesis in planta.

Stop to smell the roses Some roses smell beautiful, yet others only look beautiful. Magnard et al. leveraged this distinction to study the biosynthesis of geraniol, a monoterpene alcohol in rose scent (see the Perspective by Tholl and Gershenzon). Enzymes known for geraniol synthesis in other plants, such as basil, did not seem to provide that function for roses. Instead, a diphosphohydrolase, which functions in the cytoplasm of cells in rose petals, generates the geraniol emitted by fragrant roses. Identification of the enzyme and its gene enables marker-assisted breeding to put the perfume back into beauty. Science , this issue p. 81 ; see also p. 28

Machining of modern materials requires high performance tools. More than 60% of metal cutting tools used are coated to limit abrasive wear. As the harder material known to man, diamond and consequently Chemical Vapour Deposited (CVD) diamond coatings allow to increase performances of tungsten carbide tools, i.e. tool life, machined surface quality, and to decrease costs. However, CVD diamond coated tools quality is very dependent on the surface preparation as much as the fabrication process parameters. This paper aims to discuss the influence of pretreatments before deposition, and thermal stresses induced by the cooling operation. Diamond deposition process is described emphasizing the role of every step and its function. Some numerical simulations of the residual stresses at the interface are presented, enlightening that tool geometry is an important factor while using a coating, and that tools must be designed for the diamond coating.

Diploid hybrid speciation in plants is often accompanied by rapid ecological divergence between incipient neospecies and their parental taxa. One plausible means by which novel adaptation in hybrid lineages may arise is transgressive segregation, that is, the generation of extreme phenotypes that exceed those of the parental lines. Early generation (BC2) hybrids between two wild, annual sunflowers, Helianthus annuus and Helianthus petiolaris, were used to study directional selection on transgressive characters associated with the origin of Helianthus paradoxus, a diploid hybrid species adapted to extremely saline marshes. The BC2 plants descended from a single F1 hybrid backcrossed toward H. petiolaris. The strength of selection on candidate adaptive traits in the interspecific BC2 was measured in natural H. paradoxus salt marsh habitat. Positive directional selection was detected for leaf succulence and Ca uptake, two traits that are known to be important in salt stress response in plants. Strong negative directional selection operated on uptake of Na and correlated elements. A significant decrease in trait correlations over time was observed in the BC2 population for Na and Ca content, suggesting an adaptive role for increased Ca uptake coupled with increased net exclusion of Na from leaves. Patterns of directional selection in BC2 hybrids were concordant with character expression in the natural hybrid species, H. paradoxus, transplanted into the wild. Moreover, the necessary variation for generating the H. paradoxus phenotype existed only in the BC2 population, but not in samples of the two parental species, H. annuus and H. petiolaris. These results are consistent with the hypothesis that transgressive segregation of elemental uptake and leaf succulence contributed to the origin of salt adaptation in the diploid hybrid species H. paradoxus.

Hybridization is frequent in many organismal groups, but its role in adaptation is poorly understood. In sunflowers, species found in the most extreme habitats are ancient hybrids, and new gene combinations generated by hybridization are speculated to have contributed to ecological divergence. This possibility was tested through phenotypic and genomic comparisons of ancient and synthetic hybrids. Most trait differences in ancient hybrids could be recreated by complementary gene action in synthetic hybrids and were favored by selection. The same combinations of parental chromosomal segments required to generate extreme phenotypes in synthetic hybrids also occurred in ancient hybrids. Thus, hybridization facilitated ecological divergence in sunflowers.

The primary requirement for a new diploid species to arise via hybridization is ecological divergence from its parental species. Ecological divergence protects the nascent hybrid species from competition with its progenitor species and may contribute to reproductive isolation. However, the means by which hybridization might facilitate the necessary adaptive transitions are poorly understood. Here, we report the results of a glasshouse experiment in which 42 morphological and ecophysiological traits were measured in three hybrid sunflower species (Helianthus anomalus, Helianthus deserticola, and Helianthus paradoxus) and their parental species (Helianthus annuus and Helianthus petiolaris). A surprisingly high proportion of traits were extreme relative to the parental species (24%, 20%, and 39% of traits in H. anomalus, H. deserticola, and H. paradoxus, respectively). Most of the extreme traits have previously been reported in the literature as adaptations to dune (H. anomalus), high‐desert (H. deserticola)...

Single- or low-copy nuclear sequences are now widely employed for phylogenetic reconstruction. In a new paper, Ferguson and Sang apply this approach to allotetraploid species of peonies Paeonia and document the first case of natural homoploid hybrid speciation between tetraploid taxa. This surprising finding could shed light on the relationship between the two main pathways of hybrid speciation: allopolyploidization and homoploid hybrid speciation. In addition, this work illustrates both the promise and uncertainty associated with the reconstruction of reticulate phylogenies using molecular tools.

Analytical capillary zone electrophoresis (CZE) conditions including concentration, pH value and nature (complexing or non-complexing) of the running buffer with or without the addition of methanol, capillary temperature and applied voltage, were studied in order to optimize the separation and resolution of a mixture of 13 C-glycosylflavones and one flavone O-glucoside. Factors primarily responsible for differences in electrophoretic mobility of flavone C-glycosides are identical to those defined from the separation of flavonoid O-glycosides, i.e. number and position of the free hydroxy groups on the flavone skeleton, and number and type of attached sugar groups. Nevertheless, an increase in the pH value from 9 to 10 of the borate running buffer affects the elution order: such an increase induces greater relative electrophoretic mobilities of C-glycoside derivatives with a free hydroxy group at C-4′ compared with those of luteolin C-glycoside derivatives. This change in the migration order could be explained both by a decrease of the net charge linked to an increase and stability of the borate–luteolin complexation and by an increase in molecular size. Moreover the 6-C-glycosylflavones present electrophoretic mobilities lower than their homologous 8-C-glucosyl isomers. Finally, the study of C-glucosylflavones from 18 different samples of Passiflora incarnata by CZE shows a great variability in the qualitative composition. Copyright © 2000 John Wiley & Sons, Ltd.

The ACT STATIS method, a multi-table comparison, was applied to 62 Rosa species to be clustered into four sections (Carolinae, Cinnamomeae, Pimpinellifoliae and Synstylae); the data sets were dealing with morphology (15 criteria), anthocyanin pattern (10 compounds), flavonol heteroside pattern (26 compounds) and superoxide dismutase isozyme (SOD) polymorphism (11 bands). This method appeared very powerful to recognize the rose sections and to set up a marker hierarchy which places at the first level the flavonol hetero­ side pattern, then the morphological data, the SOD isozyme data and finally the anthocyanin pattern. The correlation studies between the markers underlined the relatively common view by means of flavonol patterns and the morphological features

Sixty-seven species belonging to four sections of the genus Rosa were analysed by means of flavonoids and isozyme polymorphism (esterase, leucine amino peptidase and superoxyde dismutase). A clear delineation of most of Pimpinellifoliae and Synstylae was observed. A more subtle dichotomy was observed for the Cinnamomeae, which showed two groups: the first very close to the hypothetical ancestor of wild roses, the second much more advanced. The Carolinae section was associated with the first group of Cinnamomeae.

Rosa‘Complicata’, a widely cultivated rose recently investigated by ‘fingerprinting’ techniques, is shown to have a surprisingly uncomplicated history. The origin of this rose is explored and its connection with the wild Rosa complicata Grenier (1864), which was described from the French Jura, is discussed. A colour illustration and description are provided.

In order to study the polymorphism of the enzyme systems of rose cultivars, experimental conditions were determined to simultaneously extract three systems: esterase (EST), leucine aminopeptidase (LAP) and superoxide dismutase (SOD) which gave up to 9, 7 and 9 bands, respectively. The influence of environmental conditions on the polymorphism level was taken into account. Finally, the computation of the Jaccard distances from the distribution of the isozyme bands led to the improvement of the identification process within an Ancient Rose cultivar collection.

Summary The chemical markers such as phenolic compounds, have been extensively used in botanical chemosystematic studies; these last mainly concerned the high taxonomic levels: order, family, genus. In consequence of new more sensitive and automatic analytical procedures, it is possible to approach the metabolic (phenolic) profile of individual genotypes: so the Micromolecular Biology is born, concerned with the organisation and functioning of plant populations. Three examples will give support to this proposal: Dactylis glomerata, Rosa x hybrida, Lotus corniculatus.

The floral flavonoid metabolism of ancient rose varieties of key importance in the rose selection process was investigated by means of High Performance Liquid Chromatography. The phenolic variation organised by means of chemometrics revealed biochemical communities clustered around the founder species of modern roses: R. chinensis, R. gallica and R. moschata .

Background For centuries roses have been selected based on a number of traits. Little information exists on the genetic and molecular basis that contributes to these traits, mainly because information on expressed genes for this economically important ornamental plant is scarce. Results Here, we used a combination of Illumina and 454 sequencing technologies to generate information on Rosa sp. transcripts using RNA from various tissues and in response to biotic and abiotic stresses. A total of 80714 transcript clusters were identified and 76611 peptides have been predicted among which 20997 have been clustered into 13900 protein families. BLASTp hits in closely related Rosaceae species revealed that about half of the predicted peptides in the strawberry and peach genomes have orthologs in Rosa dataset. Digital expression was obtained using RNA samples from organs at different development stages and under different stress conditions. qPCR validated the digital expression data for a selection of 23 genes with high or low expression levels. Comparative gene expression analyses between the different tissues and organs allowed the identification of clusters that are highly enriched in given tissues or under particular conditions, demonstrating the usefulness of the digital gene expression analysis. A web interface ROSAseq was created that allows data interrogation by BLAST, subsequent analysis of DNA clusters and access to thorough transcript annotation including best BLAST matches on Fragaria vesca, Prunus persica and Arabidopsis. The rose peptides dataset was used to create the ROSAcyc resource pathway database that allows access to the putative genes and enzymatic pathways. Conclusions The study provides useful information on Rosa expressed genes, with thorough annotation and an overview of expression patterns for transcripts with good accuracy.

International audience; Cultivated for centuries, the varieties of rose have been selected based on a number of flower traits. Understanding the genetic and molecular basis that contributes to these traits will impact on future improvements for this economically important ornamental plant. In this study, we used scanning electron microscopy and sections of meristems and flowers to establish a precise morphological calendar from early rose flower development stages to senescing flowers. Global gene expression was investigated from floral meristem initiation up to flower senescence in three rose genotypes exhibiting contrasted floral traits including continuous versus once flowering and simple versus double flower architecture, using a newly developed Affymetrix microarray (Rosa1_Affyarray) tool containing sequences representing 4765 unigenes expressed during flower development. Data analyses permitted the identification of genes associated with floral transition, floral organs initiation up to flower senescence. Quantitative real time PCR analyses validated the mRNA accumulation changes observed in microarray hybridizations for a selection of 24 genes expressed at either high or low levels. Our data describe the early flower development stages in Rosa sp, the production of a rose microarray and demonstrate its usefulness and reliability to study gene expression during extensive development phases, from the vegetative meristem to the senescent flower.

International audience; In order to improve the oxidation resistance of graphite at high temperatures, graphite surfaces are modified by two silicidation processes involving reactive infiltration of molten silicon or, alternatively, of gaseous silicon monoxide. The resistance to oxidation of silicided graphite is studied by cyclic oxidation tests performed under a dry air flux at temperatures in the range 1550-1600 degrees C. During oxidation three successive regimes are evidenced: (i) initial growth of a passive silica layer on the continuous SiC superficial layer responsible for the remarkable oxidation resistance at 1550 degrees C; (ii) then, slow mass consumption in the intermediate composite SiC C region; (iii) and finally, rapid local consumption of the underlying non-infiltrated porous graphite. The temporal stability of the silicided layer in air is analyzed and the reactions affecting this stability are identified. The analysis interprets the experimental findings in a satisfactory manner, especially the dramatical variation with temperature of silicided graphite lifetime observed in this temperature range. (C) 2011 Elsevier Ltd. All rights reserved.

Background Roses have been cultivated for centuries and a number of varieties have been selected based on flower traits such as petal form, color, and number. Wild-type roses have five petals (simple flowers), whereas high numbers of petals (double flowers) are typical attributes of most of the cultivated roses. Here, we investigated the molecular mechanisms that could have been selected to control petal number in roses. Methodology/Principal Findings We have analyzed the expression of several candidate genes known to be involved in floral organ identity determination in roses from similar genetic backgrounds but exhibiting contrasting petal numbers per flower. We show that the rose ortholog of AGAMOUS (RhAG) is differentially expressed in double flowers as compared to simple flowers. In situ hybridization experiments confirm the differential expression of RhAG and demonstrate that in the double-flower roses, the expression domain of RhAG is restricted toward the center of the flower. Conversely, in simple-flower roses, RhAG expression domain is wider. We further show that the border of RhAG expression domain is labile, which allows the selection of rose flowers with increased petal number. Double-flower roses were selected independently in the two major regions for domestication, China and the peri-Mediterranean areas. Comparison of RhAG expression in the wild-type ancestors of cultivated roses and their descendants both in the European and Chinese lineages corroborates the correlation between the degree of restriction of RhAG expression domain and the number of petals. Our data suggests that a restriction of RhAG expression domain is the basis for selection of double flowers in both the Chinese and peri-Mediterranean centers of domestication. Conclusions/Significance We demonstrate that a shift in RhAG expression domain boundary occurred in rose hybrids, causing double-flower phenotype. This molecular event was selected independently during rose domestication in Europe/Middle East and in China.

Much of our knowledge of speciation genetics stems from quantitative trait locus (QTL) studies. However, interpretations of the size and distribution of QTL underlying species differences are complicated by differences in the way QTL magnitudes are estimated. Also, many studies fail to exploit information about QTL directions or to compare inter- and intraspecific QTL variation. Here, we comprehensively analyze an extensive QTL data set for an interspecific backcross between two wild annual sunflowers, Helianthus annuus and H. petiolaris, interpret different estimates of QTL magnitudes, identify trait groups that have diverged through selection, and compare inter- and intraspecific QTL magnitudes. Our results indicate that even minor QTL (in terms of backcross variance) may be surprisingly large compared to levels of standing variation in the parental species or phenotypic differences between them. Morphological traits, particularly flower morphology, were more strongly or consistently selected than life history or physiological traits. Also, intraspecific QTL were generally smaller than interspecific ones, consistent with the prediction that larger QTL are more likely to spread to fixation across a subdivided population. Our results inform the genetics of species differences in Helianthus and suggest an approach for the simultaneous mapping of inter- and intraspecific QTL.

Fifteen Rosa cultivated races were described by means of phenotypic frequencies (11 tables). Two groups of correlated contingency tables were identified by ACT-STATIS (Analyse Conjointe de Tableaux - Structuration de Tableaux à Trois Indices de la Statistique) interstructure analysis. Three data sets appeared to be independent from the others. Typologies of races were obtained after ACT-STATIS compromise analyses for the two groups of correlated tables, and after Principal Component Analyses for the independent data sets. Each typology was original and variously influenced by genealogical structure, mutation or artificial selection pressures. A weighted synthesis was attempted in order to build a taxonomy of races taking into account these diversity factors. The good agreement between the resulting classification and the assumptions about the history of Rosa domestication advocated for a wider utilization of ACT-STATIS and RV coefficient when the relationships between individuals or populations have to be studied on the basis of their similarities.

Les sujets présentés donnent un aperçu des traitements particuliers qui ont été réalisés sur certains des profils alpins suisses de sismique réflection. Les exemples sont tirés du profil Est et des lignes de Zermatt et du Val d'Anniviers du profil Ouest. Ces sujets ont été choisis en fonction de problèmes spécifiques que pose la sismique dans les Alpes. Ils concernent les corrections statiques résiduelles, l'influence des pendages sur les vitesses apparentes (traitement ''dip move out"), le traitement en pseudo-3 dimensions ainsi que l'utilisation des stacks par distance de tir. Les résultats obtenus montrent que dans les régions à tectonique complexe, comme les Alpes, des traitements particuliers s' imposent pour améliorer la continuité des réflecteurs. De plus, il est souvent impossible de synthétiser sur une seule section sismique toutes les informations extraites des différentes phases du traitement. Il est donc nécessaire de baser l'interprétation sur plusieurs documents sismiques. ln an attempt to extract the maximum information from the Swiss Alpine seismic reflection profiles FNP/PNR 20 (National Research Program 20) East and West, we have tested a number of special processing procedures on the data, including automatic source-receiver-dependent static corrections, dip move out (DMO) corrections, pseudo-three dimensional stacking and offset-dependent stacking. Reliable static corrections are particularly important for data collected in regions of extreme topography, such as the Alps. We have calculated Standard and residual statics that correct for topography and complexities associated with changing geology along the various ray paths. Residual static corrections were computed for several source-receiver configurations. To properly image both shallow and steeply dipping events and to improve the overall quality of the stacked data prior to migration, dip move out corrections were applied to the data. We have taken advantage of the crooked character of one of the recording lines to produce short seismic sections that are perpendicular to the main trend of the profile. Using the apparent dips obtained from these "cross-lines" stacks, an improved in-line stack was automatically computed and absolute dips estimared. Finally, in very complex terrains some imponant events only appear at certain source-receiver offsets. We have discovered a number of dipping reflections on offset-dependent stacks that are not obvious on stacks of the full data set. For reliable interpretations of seismic reflection data from areas of complex geology, our results demonstrate that it is often useful to work with a suite of seismic sections that have been treated by different processes.