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International audience; Underspecified nouns (Nss), those that can appear in a specificational construction (1) of the form 'Leur ambition a été d’innover' “Their ambition was to innovate”, are often also predicates governing arguments in an elementary sentence (2) of the form 'Ils ont eu l’ambition d’innover' “They had the ambition to innovate”, where Nss is the predicate accompanied by a support verb and its arguments N0 and N1. We studied nouns entering in both constructions (1) and (2) with the same meaning, and found three situations. With nouns such as 'ambition', (1) and (2) have almost the same meaning. With other entries, such as 'souvenir' “memory” and 'preuve' “proof”, the two constructions are not equivalent: the sentential predicative of (1) is absent from (2), whereas the N1 argument of (2) can appear as a prepositional complement of Nss in (1), and often (as with 'souvenir') specifies the theme of the content of the sentential predicative of (1). Finally, nouns such as 'embarras' “embarrassment” are not typical Nss because the sentential predicative of (1) has a causal role; it has not the same content as N1. Thus, in the 'mémoire'/'preuve' and 'embarras' types, (1) seems to involve several elementary sentences.; Les noms sous-spécifiés (Nss), qui peuvent apparaitre dans une construction spécificationnelle (1), de la forme "Leur ambition a été d’innover", sont par ailleurs souvent des prédicats régissant des arguments, dans une phrase élémentaire (2) de la forme "Ils ont eu l’ambition d’innover", où Nss est le prédicat accompagné d’un verbe support et de ses arguments N0 et N1. Nous avons étudié des noms entrant à la fois dans les deux constructions (1) et (2) avec le même sens, et trouvé trois cas de figure. Avec des noms tels que "ambition", (1) et (2) ont presque le même sens. Dans d’autres entrées, telles que "souvenir" et "preuve", les deux constructions ne sont pas équivalentes : l’attribut phrastique de (1) est absent de (2), tandis que l’argument N1 de (2) peut apparaitre comme complément de nom du Nss sujet dans (1), et spécifie souvent (c’est le cas pour "souvenir") le thème du propos contenu dans l’attribut phrastique de (1). Enfin, d’autres noms tels que "embarras" ne sont pas des Nss typiques car l’attribut phrastique de (1) y joue un rôle causal ; il n’a pas le même contenu que N1. Ainsi, dans les types "souvenir"/"preuve" et "embarras", (1) est à analyser comme une combinaison de plusieurs phrases élémentaires.

Avant de cerner l’identitème, objet de l’identité, revenons sur une notion conflictuelle au carrefour de nombreuses disciplines. La réflexion sur l’identité n’est pas nouvelle (pour un bref historique, voir Moore et Brohy, 2013) et cet avant-propos ne suffira pas à énumérer toutes les recherches associées. Il a donc fallu pratiquer des coupes sombres. Car l’identité rassemble des chercheurs plus ou moins connus de tous horizons : philosophie (L’Herne), psychologie (Hofstede, Vinsonneau), psychologie sociale (Mucchielli), sociologie (Bourdieu), sociolinguistique (Moore), ethnologie/anthropologie (Escola), anthropologie (Lévi-Strauss, Remotti, Todorov), médiologie/analyse des discours médiatiques (Schlesinger), histoire (Braudel), histoire anthropologique (Gruzinski), littérature (Maalouf), sémiotique (Calame) ou encore management interculturel (Livian) . Un même chercheur peut puiser dans plusieurs disciplines : ainsi, Boyer endosse les casquettes de chercheur en sociolinguistique, psychologie sociale, sémiotique et analyse des discours médiatiques, ou encore Morin celles de philosophe et de sociologue.

Eucalypts are the most planted trees worldwide, but most of them are frost sensitive. Overexpressing transcription factors for CRT-repeat binding factors (CBFs) in transgenic Eucalyptus confer cold resistance both in leaves and stems. While wood plays crucial roles in trees and is affected by environmental cues, its potential role in adaptation to cold stress has been neglected. Here, we addressed this question by investigating the changes occurring in wood in response to the overexpression of two CBFs, taking advantage of available transgenic Eucalyptus lines. We performed histological, biochemical, and transcriptomic analyses on xylem samples. CBF ectopic expression led to a reduction of both primary and secondary growth, and triggered changes in xylem architecture with smaller and more frequent vessels and fibers exhibiting reduced lumens. In addition, lignin content and syringyl/guaiacyl (S/G) ratio increased. Consistently, many genes of the phenylpropanoid and lignin branch pathway were upregulated. Most of the features of xylem remodeling induced by CBF overexpression are reminiscent of those observed after long exposure of Eucalyptus trees to chilling temperatures. Altogether, these results suggest that CBF plays a central role in the cross-talk between response to cold and wood formation and that the remodeling of wood is part of the adaptive strategies to face cold stress.

To concede firstly means “admitting/acknowledging” something based on a statement X from a source L1 other than the speaker L2 who concedes, the meaning of a proposition P included in X. But if L2 acknowledges P, he does not accept the conclusion expected by L1, because conceder (to concede) generally implies a mais (but). Concéder (to concede)… mais (but) then opens the way to a concessive sequence introducing a conclusion Q2, which is different from conclusion Q1 resulting from P (the one expected by L1). In a pragmatic, semantic approach we show how, whilst raising disagreement on a point with an interlocutor, to concede introduces a part agreement, then a second disagreement with the interlocutor. The logical relationship reflecting this second disagreement between Q2 and Q1 will differ depending on the corresponding type of concessive – logical, corrective or argumentative. Concéder (conceder) consiste en primer lugar en responsabilizarse, a partir de un enunciado X procedente de una fuente L1 distinta de la del locutor L2 que concede, del sentido de una aserción P incluída en X. Pero si L2 se responsabiliza de P, no asume la conclusión esperada por L1, ya que concéder (conceder) implica generalmente un mais (pero). Concéder (conceder)… mais (pero) abre entonces una secuencia concesiva introduciendo una conclusión Q2 diferente de una conclusión Q1 que se desprende de P (aquella esperada por L1). En un enfoque semántico-pragmático mostraremos cómo, al mismo tiempo que se abre un desacuerdo sobre un punto con el interlocutor, concéder (conceder) introduce un acuerdo parcial, y después un segundo desacuerdo con el interlocutor. La relación lógica que traduce este segundo desacuerdo entre Q2 y Q1 será distinto según el tipo concesivo correspondiente – lógico, rectificativo o argumentativo. Concéder revient en premier lieu à prendre en charge, à partir d’un énoncé X provenant d’une source L1 autre que le locuteur L2 qui concède, le sens d’une assertion P incluse dans X. Mais si L2 prend en charge P, il n’en assume pas la conclusion attendue par L1, car concéder implique généralement un mais. Concéder… mais ouvre alors une séquence concessive introduisant une conclusion Q2 différente d’une conclusion Q1 découlant de P (celle attendue par L1). Dans une approche sémantico-pragmatique nous montrons comment, tout en levant un désaccord sur un point avec l’interlocuteur, concéder introduit un accord partiel, puis un second désaccord avec l’interlocuteur. La relation logique traduisant ce second désaccord entre Q2 et Q1 va différer selon le type concessif correspondant – logique, rectificatif ou argumentatif.

Although eucalypts are the most planted hardwood trees worldwide, the majority of them are frost sensitive. The recent creation of frost-tolerant hybrids such as Eucalyptus gundal plants (E. gunnii × E. dalrympleana hybrids), now enables the development of industrial plantations in northern countries. Our objective was to evaluate the impact of cold on the wood structure and composition of these hybrids, and on the biosynthetic and regulatory processes controlling their secondary cell-wall (SCW) formation. We used an integrated approach combining histology, biochemical characterization and transcriptomic profiling as well as gene co-expression analyses to investigate xylem tissues from Eucalyptus hybrids exposed to cold conditions. Chilling temperatures triggered the deposition of thicker and more lignified xylem cell walls as well as regulation at the transcriptional level of SCW genes. Most genes involved in lignin biosynthesis, except those specifically dedicated to syringyl unit biosynthesis, were up-regulated. The construction of a co-expression network enabled the identification of both known and potential new SCW transcription factors, induced by cold stress. These regulators at the crossroads between cold signalling and SCW formation are promising candidates for functional studies since they may contribute to the tolerance of E. gunnii × E. dalrympleana hybrids to cold.

International audience; In this study meant to be a preliminary to a larger one on French exclamative sentences with à quel point (AQP), we will analyse the distributions of PPs à un point X (AUPX), which have an indefinite determiner inside them. In effect, these expressions are supposed to underlie an exclamative (or interrogative) AQP according to a presuppositional hypothesis on exclamative or interrogative wh-sentences (cf. Michaelis & Lambrecht). We will demonstrate that contrary to general distribution of quel, AQP possesses only an indirect exclamative use, excluding direct exclamative, direct and indirect interrogative uses, which contradicts the acceptability judgements given by linguists like J.-C. Milner. AUPX expressions linked to AQP receive, indeed, an interpretation of high degree because of 1) the lexical meaning of “limit/threshold” the noun point takes on in these expressions and of 2) the limitation imposed on the paradigm of modifieurs, which excludes a free variation, prerequisite for quel interrogatives. They can thus be considered a construction. The modifiers (adjective or relative), in complementary distribution to an exclamative intonation, describe the incredulity or unspeakability of the speaker, translating his/her subjective evaluation visa-vis of the high degree. This type of modifier is the one which functions as the main predicate in an indirect exclamative sentence. AQP is simply a subordinate variant of AUPX.; La construction à un point X en relation avec l'exclamative en à quel point Résumé. Dans cette étude préalable à une description plus générale des exclamatives en à quel point (AQP), nous examinons les distributions des SP à un point X (AUPX) comportant un déterminant indéfini. Ces derniers doivent sous-tendre AQP exclamatif (et interrogatif) selon une hypothèse présuppositionelle sur les phrases interrogatives et exclamatives mettant en jeu un élément Qu-(cf. Michaelis & Lambrecht). Nous démontrons que, contrairement à la distribution générale de quel, AQP ne possède que l'emploi exclamatif indirect, excluant l'exclamatif direct et les interrogatifs direct et indirect, ce qui va à l'encontre du jugement d'acceptabilité de linguistes comme J.-C. Milner. Les syntagmes AUPX reliés au syntagme AQP expriment exclusivement le haut degré, en raison 1) du sens lexical de « seuil/limite » que le nom point y revêt et 2) d'un paradigme de modifieurs qui exclut une variation libre, condition préalable de la question en quel. Ils peuvent être considérés comme une construction. Ces modifieurs (adjectif ou relatif), en distribution complémentaire avec une forte intonation exclamative, décrivent l'incrédulité ou l'indicibilité du locuteur, traduisant son appréciation subjective vis-à-vis du haut degré. Ils constituent souvent le prédicat principal d'une exclamative indirecte. AQP n'est alors qu'une variante syntaxique subordonnée d'AUPX. Abstract. à un point X construction in relation to à quel point exclamation.

Les ellipses du complement dans les expressions situationnelles relevent du paradoxe, traduisant un chevauchement entre langue et discours. Tout en recevant un « remplissage » situationnel souvent imprevisible, elles sont preconstruites d’apres les regles de la syntaxe et les proprietes lexicales des verbes correspondants et apparaissent meme dans des constructions sui generis qui relevent de la Grammaire des constructions.

The term cold hardiness or freezing tolerance is used to represent, in a general sense, the ability of plants to adapt to and withstand freezing temperatures. It is a complex, multigenic trait that is too often viewed as a single entity when in fact it is composed of many aspects, all of which can be to some extent viewed as genetically distinct. Advances in molecular biology and genomics have provided significant advances in understanding how plants respond to low temperature and acquire freezing tolerance. Among the most important discoveries has been the identification of the CBF/DREB transcription factor. This transcription factor, along with its regulators such as ICE transcription factors, play a major role in sensing low temperature, initiating the process of cold acclimation, and inducing the expression of a large set of cold-regulated genes. These latter genes are presumed to ameliorate injury to plant cells as a result of freeze-induced desiccation and the presence of extracellular ice. The pres...

Absent des etudes linguistiques sur les noms d’emotion, trac est presente par les dictionnaires comme synonyme de peur. Or, si le second peut etre substitue au premier, l’inverse n’est pas toujours possible (avoir (peur / *le trac) a la vue d’une souris). Nous fondant sur des caracteristiques linguistiques concernant l’argument experienceur et l’argument cause, nous montrons que trac est plus proche de l’apprehension : c’est une emotion anticipatoire que l’on ressent a l’idee d’un jugement qui va etre porte sur soi avant un evenement social ou devant une personne ayant une fonction sociale. Il apparait etre l’affaire du sujet : le trac de Luc ne peut s’interpreter que comme un genitif subjectif. L’absence d’objet (*le trac de quelqu’un, quelque chose) indique qu’il s’agit d’une emotion dont l’objet n’est pas identifiable.

Plants respond to low temperatures through an intricately coordinated transcription network which results in cold acclimation, a phenomenon by which plants increase their freezing tolerance. To analyse the global transcriptome of Eucalyptus gunnii cold-acclimated leaves, 2,662 ESTs were classified by FunCat and the corresponding transcripts quantified throughout a cold acclimation programme using macro-array technique. This combined analysis resulted in the description of the temporal patterns of gene expression with regard to their identity and corresponding functional categories. This paper proposes a predictive hierarchical classification of the main protective mechanisms likely to participate in the increased cold tolerance of E. gunnii. Given the time course and level of the LEA/dehydrin accumulation, the cryoprotection through proteins may explain most of the hardening. This cryoprotection would be completed by sugar synthesis (raffinose and maltose). As a permanent response, red-ox regulation and protection of membranes or macromolecules against peroxidation look mainly associated with metallothioneins. A limited part of cold response seems to be dedicated to dehydration avoidance through osmoprotectants or to frost avoidance through antifreeze proteins and deposition of cuticle wax.

Annotation of the Eucalyptus grandis genome showed a large amplification of the dehydration-responsive element binding 1/C-repeat binding factor (DREB1/CBF) group without recent DREB2 gene duplication compared with other plant species. The present annotation of the CBF and DREB2 genes from a draft of the Eucalyptus gunnii genome sequence reveals at least one additional CBF copy in the E. gunnii genome compared with E. grandis, suggesting that this group is still evolving, unlike the DREB2 group. This study aims to investigate the redundancy/neo- or sub-functionalization of the duplicates and the relative involvement of the two groups in abiotic stress responses in both E. grandis and E. gunnii (lower growth but higher cold resistance). A comprehensive transcriptional analysis using high-throughput quantitative real-time polymerase chain reaction (qRT-PCR) was performed on leaves, stems and roots from the two Eucalyptus species after cold, heat or drought treatment. A large CBF cluster accounted for most of the cold response in all the organs, whereas heat and drought responses mainly involved a small CBF cluster and the DREB2 genes. In addition, CBF putative target genes, known to be involved in plant tolerance and development, were found to be cold-regulated. The higher transcript amounts of both the CBF and target genes in the cold tolerant E. gunnii contrasted with the higher CBF induction rates in the fast growing E. grandis. Altogether, the present results, in agreement with previous data about Eucalyptus transgenic lines over-expressing CBF, suggest that these factors, which promote both stress protection and growth limitation, participate in the trade-off between growth and resistance in this woody species.

Summary Two C-repeat binding factor genes (EguCBF1a ⁄ b), isolated from E. gunnii and differentially cold-regulated, were constitutively overexpressed in a cold-sensitive Eucalyptus hybrid. In addition to the expected improvement on freezing tolerance, some resulting transgenic lines (EguCBF1a-OE and EguCBF1b-OE) exhibited a decrease in stomata density and an over-accumulation of anthocyanins also observed to a lesser extent in a cold-acclimated control plant. Given that the induction of five putative CBF target genes was observed in CBF-overexpressing lines as well as in the coldacclimated control line, these phenotypes might be related to cold acclimation. In comparison with the control plant, the most altered transgenic line (EguCBF1a-OE A1 line), exhibited reduced growth and better water retention capacity. This modified phenotype includes reduced leaf area and thickness associated with a decrease in cell size, as well as a higher oil gland density and a wax deposition on the cuticle. Surprisingly, the EguCBF1b-OE B9 line, with a level of transgene expression equivalent to the A1 line, showed a less marked phenotype, suggesting a difference in transactivation efficiency between EguCBF1A and B factors. The features of these transgenic lines provide the first signs of adaptive mechanisms controlled by CBF transcription factors in an evergreen broad-leaved tree. These data also open new prospects towards genetic improvement on Eucalyptus for freezing tolerance.

Le dictionnaire electronique Locutions en francais (LEF) de J. Dubois et F. Dubois-Charlier (2004) vise moins l’exhaustivite lexicale que la couverture des patrons (« schemes ») syntaxiques dans lesquels s’inserent les locutions. Si LEF pretend enregistrer l’ensemble des constructions typiques des locutions, est-ce que tout ce que l’on peut rassembler sous cette etiquette entre effectivement dans le cadre de LEF ? Partant du verbe dire dans des expressions formulaires a fonction situationnelle, nous nous proposons de voir, a partir d’exemples recenses dans differents corpus et dictionnaires, quelle couverture offre LEF. Parmi les expressions non recensees dans LEF, nous mettons a l’epreuve la pertinence du principe d’exhaustivite : soit les locutions non enregistrees peuvent s’inscrire dans un schema deja dessine dans LEF – et les patrons syntaxiques recenses auraient alors une capacite predictive –, soit les exemples non repertories ne s’inscrivent dans aucun patron. Dans ce dernier cas, nous montrons qu’il suffit, pour regulariser les exemples, de preciser le sous-type de phrase « focalisee » ou de rattacher la construction verbale sans objet exprime a une construction de dire recensee dans Les Verbes francais (LVF) de J. Dubois et F. Dubois Charlier (1997).

A cDNA library was constructed from leaves of a cold-acclimated Eucalyptus gunnii elite clone and 13,056 ESTs were sequenced. When the 5,457 unique sequences were compared with Arabidopsis, rice, and poplar datasets, more than 38% of no-hits were found and the best annotation was provided by the woody perennial poplar database. However, among the 62% of sequences that could be annotated, the vast majority (87.5%) was found to be common to the four compared plant species, which shows how highly conserved this gene pool is across the plant kingdom. When the distribution of the annotated sequences was studied according to the Gene Ontology classification, some typical features of the dehydrative stress transcriptome were observed. In particular, genes from sugar metabolism and, above all, those induced by stress or external stimuli were well represented (6% in total). In addition, the library was found to contain a substantial number of ESTs encoding putative transcription factors including CBF (CRT-Binding Factor). The enrichment of this library with stress-related genes was strongly suggested by the high redundancy (up to 300 ESTs) of several genes known to be involved in cell protection such as the PCP (Pollen Coat Protein), Lti6b (Low temperature induced) or metallothionein. It was further confirmed by demonstrating the cold induction of a set of representative genes through Real Time-PCR. All these characteristics make this Eucalyptus EST collection very suitable for investigating the molecular basis of cold tolerance in a woody perennial and for isolating important or new candidate frost tolerance genes.

Plant organisms contain a large number of genes belonging to numerous multigenic families whose evolution size reflects some functional constraints. Sequences from eight multigenic families, involved in biotic and abiotic responses, have been analyzed in Eucalyptus grandis and compared with Arabidopsis thaliana. Two transcription factor families APETALA 2 (AP2)/ethylene responsive factor and GRAS, two auxin transporter families PIN-FORMED and AUX/LAX, two oxidoreductase families (ascorbate peroxidases [APx] and Class III peroxidases [CIII Prx]), and two families of protective molecules late embryogenesis abundant (LEA) and DNAj were annotated in expert and exhaustive manner. Many recent tandem duplications leading to the emergence of species-specific gene clusters and the explosion of the gene numbers have been observed for the AP2, GRAS, LEA, PIN, and CIII Prx in E. grandis, while the APx, the AUX/LAX and DNAj are conserved between species. Although no direct evidence has yet demonstrated the roles of these recent duplicated genes observed in E. grandis, this could indicate their putative implications in the morphological and physiological characteristics of E. grandis, and be the key factor for the survival of this nondormant species. Global analysis of key families would be a good criterion to evaluate the capabilities of some organisms to adapt to environmental variations.

A clone very similar to the maize sucrose export defective (SXD1) gene encoding a tocopherol cyclase (TC) was isolated from a Eucalyptus cold-acclimation downregulated cDNA library and was designated EgSXD1 (Eucalyptus gunnii sucrose export defective 1). As expected, the synthesis of tocopherols (vitamin E) from 2,3-dimethyl-5-phytyl-1,4-benzoquinol by the recombinant protein demonstrated that the EgSXD1 gene product is a TC. Northern hybridizations with RNA isolated from cell suspension cultures clearly showed a fast EgSXD1 downregulation by cold. This strong repression also evidenced by real-time reverse transcription polymerase chain reaction analysis on plantlets was associated with both an increased cold tolerance and a slight but significant decrease in leaf tocopherol content. These results, contrary to the commonly reported tocopherol accumulation after drought or salt stress, raise the question of the role of this gene regulation in cold hardening, which is clearly different from a direct antioxidant protection.

In angiosperms, lignin is built from two main monomers, coniferyl and sinapyl alcohol, which are incorporated respectively as G and S units in the polymer. The last step of their synthesis has so far been considered to be performed by a family of dimeric cinnamyl alcohol dehydrogenases (CAD2). However, previous studies on Eucalyptus gunnii xylem showed the presence of an additional, structurally unrelated, monomeric CAD form named CAD1. This form reduces coniferaldehyde to coniferyl alcohol, but is inactive on sinapaldehyde. In this paper, we report the functional characterization of CAD1 in tobacco (Nicotiana tabacum L.). Transgenic tobacco plants with reduced CAD1 expression were obtained through an RNAi strategy. These plants displayed normal growth and development, and detailed biochemical studies were needed to reveal a role for CAD1. Lignin analyses showed that CAD1 down-regulation does not affect Klason lignin content, and has a moderate impact on G unit content of the non-condensed lignin fraction. However, comparative metabolic profiling of the methanol-soluble phenolic fraction from basal xylem revealed significant differences between CAD1 down-regulated and wild-type plants. Eight compounds were less abundant in CAD1 down-regulated lines, five of which were identified as dimers or trimers of monolignols, each containing at least one moiety derived from coniferyl alcohol. In addition, 3-trans-caffeoyl quinic acid accumulated in the transgenic plants. Together, our results support a significant contribution of CAD1 to the synthesis of coniferyl alcohol in planta, along with the previously characterized CAD2 enzymes.

A procedure for A. tumefaciens-mediated genetic transformation of a juvenile E. camaldulensis clone is presented. CAD antisense full-length cDNAs from Eucalyptus gunnii or Nicotiana tabacum was introduced under the control of the CaMV 35S DE promoter. From 44 individual transgenic shoots selected by PCR analysis, 32% exhibited a significant reduction of CAD activity, up to 83%. The use of the heterologous tobacco CAD cDNA construct was less efficient (up to 65% reduction). Transcript levels in 3 lines obtained using the homologous eucalyptus cDNA confirmed the under-expression of the CAD gene, and Southern blot data indicated a low transgene copy number ranging between 1 and 3. The most down-regulated plant contained a single transgene copy. Therefore, for the first time in eucalyptus, genetically modified plantlets exhibiting a strong inhibition of CAD activity associated with decreased transcription were recovered. Five transgenic lines, transferred to the greenhouse for 10 months, went through a wood chemical analysis that showed no differences in lignin quantity (through Fourier transform infrared spectroscopy), composition (through analytical pyrolysis) or pulp yield (through Kraft pulping) compared to control trees. Despite the down-regulation of the CAD gene in this Eucalyptus species of economic interest, the lack of significant changes in lignin profiles indicates that probably the trees were not sufficiently suppressed in CAD throughout development to exhibit obvious modifications in lignin and pulping. This raises the problem of the requirements for an efficient modulation of lignification in trees such as eucalyptus.

L'A. presente une etude sur les analogies entre une expression s'appliquant a l'espace et une expression designant un domaine non-spatial en se focalisant sur les locutions prepositives (en marge de, en dehors de). Au lieu de parler de transfert du concret vers l'abstrait, l'A. parle de transfert du spatial au non-spatial. Cela l'amene a s'interroger sur la pertinence de l'ordre spatial - non-spatial et cherche a elucider cette question en etudiant la relation semantique qu'entretiennent les expressions spatiales et les expressions non-spatiales. Il parle de traits inherents, de variations de sens dues au contexte, de proprietes extralinguistiques mais son objectif est de mettre en evidence des changements syntaxiques reguliers associes au passage a l'interpretation non-spatiale

Anumber of research groups have recently succeeded in down regulating cinnamyl alcohol dehydrogenase (CAD EC.1.1.1.195) activity through genetic engineering with the aim of modifying lignin profiles in plants. In view of the expected extension of this technology to economically important plants, we have tried to obtain additional information on the best antisense constructs for maximal CAD down regulation using tobacco ( Nicotiana tabacum cv. Samsun) as a model system. A comparison of different constructs showed that efficiency was greater with homologous cDNAs (partial or full-length sequence) vs heterologous cDNA. In addition, constitutive promoters were, in our hands, more efficient than tissue (xylem) specific promoters. Although a strong down regulation of CAD gene expression was obtained for different transformants at the in vitro stage, a drop in CAD activity reduction was observed for some of them during development in the greenhouse. These different aspects are discussed in the context of future applications.

Xylem from stems of genetically manipulated tobacco plants which had had cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) activity down-regulated to a greater or lesser degree (clones 37 and 49, respectively) by the insertion of antisense CAD cDNA had similar, or slightly higher, lignin contents than xylem from wild-type plants. Fourier-transform infrared (FT-IR) microspectroscopy indicated that down-regulation of CAD had resulted in the incorporation of moieties with conjugated carbonyl groups into lignin and that the overall extent of cross-linking, particularly of guaiacyl (4-hydroxy-3-methoxyphenyl) rings, in the lignin had altered. The FT-Raman spectra of manipulated xylem exhibited maxima consistent with the presence of elevated levels of aldehydic groups conjugated to a carbon-carbon double bond and a guaiacyl ring. These maxima were particularly intense in the spectra of xylem from clone 37, the xylem of which exhibits a uniform red coloration, and their absolute frequencies matched those of coniferaldehyde. Furthermore, xylem from clone 37 was found to have a higher content of carbonyl groups than that of clone 49 or the wild-type (clone 37: clone 49: wild-type; 2.4:1.6:1.0) as measured by a degradative chemical method. This is the first report of the combined use of FT-IR and FT-Raman spectroscopies to study lignin structure in situ. These analyses provide strong evidence for the incorporation of cinnamaldehyde groups into the lignin of transgenic plants with down-regulated CAD expression. In addition, these non-destructive analyses also suggest that the plants transformed with antisense CAD, in particular clone 37, may contain lignin that is less condensed (cross-linked) than that of the wild-type.

Stable transformation of Eucalyptus globulus after biolistic DNA delivery was investigated using zygotic embryos as target material. Conditions for plant regeneration were first investigated. Six-day-old cultured embryos, which had shown to be a good target for DNA transient expression, appeared to be suitable for regeneration. Whole plants were recovered through organogenesis after particle gun bombardment. Transformation experiments were performed with a linear T-DNA fragment harbouring GUS and NPTII genes, using the biological and physical conditions defined for optimum transient expression. After 2 months on a culture medium, neoformed GUS-positive calli were obtained from the 'T-DNA' bombarded embryos. GUS-expressing calli were also recovered after selection with kanamycin following bombardment. The integration of both GUS and NPTII genes into the Eucalyptus genome was confirmed by Southern blot analysis, demonstrating stable transformation of Eucalyptus globulus cells for the first time.

Nous distinguons trois fonctionnements de à la fin dans des suites de phrases coordonnées ou juxtaposées, P0 P1, où P1 comporte l’adverbial à la fin. Dans la première partie, nous opposons sur la base de propriétés (portée, type de phrase, position dans la phrase), un emploi temporel (à la fin1) un emploi aspectuel (à la fin2) et un emploi pragmatique (à la fin3) exprimant une attitude du locuteur qui intervient pour mettre fin à un état de fait. Dans la deuxième partie, nous montrons comment, malgré ces différences, les trois emplois servent la structuration du discours. À la fin1 introduit une énumération externe (en impliquant un balancement avec au début) ; à la fin2 introduit une énumération interne, la répétition du procès dans P0 ayant pour résultat un autre procès dans P1, ce que traduisent la paraphrase avec finir par et la possibilité d’introduire une relation de subordination consécutive entre P0 et P1 ; à la fin3 vise à agir sur l’allocutaire pour qu’il mette un terme à un dire ou un faire (finissons-en) exprimé ou non dans P0. We can distinguish three functions of à la fin in the second parts of coordinated and juxtaposed phrases, P0, P1 in which P1 contains the adverbial à la fin. We first compare three uses of the adverbial on the basis of qualities (scope, type of sentence, position in the sentence): a temporal use (à la fin1), an aspectual use (à la fin2) and a pragmatic use (à la fin3) expressing an attitude on the part of the speaker who intervenes to put an end to a state of affairs. We then show how, in spite of these differences, the three uses contribute to structuring the discourse. À la fin1 introduces an external enumeration (implying opposition to au début); à la fin2 introduces an internal enumeration, the repetition of the process in P0 that results in another process in P1 which can be translated by the paraphrase finir par and the possibility of introducing a relation of consecutive subordination between P0 and P1 ; à la fin3 aims to act on the addressee so that he ends the speech or action (finissons-en) expressed or not in P0.

CBF transcription factors play central roles in the control of freezing tolerance in plants. The isolation of two additional CBF genes, EguCBF1c and EguCBF1d, from E. gunnii, one of the cold-hardiest Eucalyptus species, is described. While the EguCBF1D protein sequence is very similar to the previously characterized EguCBF1A and EguCBF1B sequences, EguCBF1C is more distinctive, in particular in the AP2-DBD (AP2-DNA binding domain). The expression analysis of the four genes by RT-qPCR reveals that none of them is specific to one stress but they are all preferentially induced by cold, except for the EguCBF1c gene which is more responsive to salt. The calculation of the transcript copy number enables the quantification of constitutive CBF gene expression. This basal level, significant for the four genes, greatly influences the final EguCBF1 transcript level in the cold. A cold shock at 4 degrees C, as well as a progressive freezing which mimics a natural frost episode, trigger a fast and strong response of the EguCBF1 genes, while growth at acclimating temperatures results in a lower but more durable induction. The differential expression of the four EguCBF1 genes under these cold regimes suggests that there is a complementary regulation. The high accumulation of the CBF transcript, observed in response to the different types of cold conditions, might be a key for the winter survival of this evergreen broad-leaved tree.

Two CBF (CRT/DRE-binding factor) homologues isolated from Eucalyptus gunnii were designated EguCBF1a and EguCBF1b and belong to a gene family which includes at least five members. Both promoter and coding sequences were found to exhibit the main characteristics of a CBF transcription activator gene and, as expected, the corresponding protein targeted the nucleus. Gene expression was quantitatively analysed using real-time reverse transcription-polymerase chain reaction (RT-PCR) after a short exposure to different environmental conditions or along a two-step cold acclimation programme with either short or long daylengths. A very strong and fast response to cold was observed, with dark conditions and cold intensity (down to 0 degrees C) having a positive effect on the magnitude of induction. The two genes under study exhibited several similar features such as light response. However, interestingly, their regulation by cold proved differential and complementary as EguCBF1a was more transiently induced by a direct and intense exposure while EguCBF1b responded to milder treatments and exhibited a longer (i.e. which started earlier and finished later) time course. During acclimation, the short daylength positively affected the freezing tolerance in the same way as it positively affected the CBF transcript accumulation, suggesting a potential involvement of these genes in the adaptive response. Although very quick after the first signal, the up-regulation of the two EguCBF1 genes unexpectedly lasted throughout the chilling culture, and new inductions were seen during the thermoperiod transitions. Using a quantitative and highly sensitive measurement of gene expression combined with the application of a cold treatment consistent with natural environmental conditions, this study provides new information on the regulation of CBF-like genes by cold in planta.

Regeneration problems are one of the main limitations preventing the wider application of genetic engineering strategies to the genus Eucalyptus. Seedlings from Eucalyptus grandis x Eucalyptus urophylla were selected according to their regeneration (adventitious organogenesis) and transformation capacity. After in vitro cloning, the best genotype of 250 tested was transformed via Agrobacterium tumefaciens. A cinnamyl alcohol dehydrogenase (CAD) antisense cDNA from Eucalyptus gunnii was transferred, under the control of the 35S CaMV promoter with a double enhancer sequence, into a selected genotype. According to kanamycin resistance and PCR verification, 120 transformants were generated. 58% were significantly inhibited for CAD activity, and nine exhibited the highest down-regulation, ranging from 69 to 78% (22% residual activity). Southern blot hybridisation showed a low transgene copy number, ranging from 1 to 4, depending on the transgenic line. Northern analyses on the 5-16 and 3-23 lines (respectively one and two insertion sites) demonstrated the antisense origin of CAD gene inhibition. With respectively 26 and 22% of residual CAD activity, these two lines were considered as the most interesting and transferred to the greenhouse for further analyses.

The effects of cinnamyl alcohol dehydrogenase (CAD, EC.1.1.1.195) down-regulation on lignin profiles of plants were analysed in four selected transgenic lines of tobacco (Nicotiana tabacum L. cv. Samsun) exhibiting different levels of CAD activity (8–56% of the control). A significant decrease in thioacidolysis yields (i.e. yield of β-O-4 linked monomers) and in the ratio of syringyl to guaiacyl monomers (S/G) was observed for three transgenic lines and the most drastic reduction (up to 50%) was correlated with the lowest level of CAD activity. Higher lignin extractability by mild alkali treatment was confirmed, and, in addition to a tenfold increase in C6-C1 aldehydes, coniferyl aldehyde was detected by high-performance liquid chromatography in the alkali extracts from the xylem of transgenic plants. In-situ polymerisation of cinnamyl aldehydes in stem sections of untransformed tobacco gave a xylem cell wall coloration strikingly similar to the reddish-brown coloration of the xylem of antisense CAD-down-regulated plants. Overall, these data provide new arguments for the involvement of polymerised cinnamyl aldehydes in the formation of the red-coloured xylem of CAD-down-regulated plants.