The middle class in Argentina: Dynamics, characteristics and implications for public policies

L'Argentine est généralement considérée comme le pays typique de la classe moyenne en Amérique latine. Pourtant, si les crises successives qui ont frappé l'économie argentine au cours des quatre dernières décennies ont manifestement affecté à la fois la taille et la stabilité de sa classe moyenne, les études universitaires manquent quant aux conséquences de ces crises sur la stratification socio-économique et sur les préférences et les attentes de la classe moyenne. Le présent article comble cette lacune en se concentrant sur la période la plus récente. Pour ce faire, nous adoptons un plan de recherche original basé sur une combinaison d'enquêtes quantitatives, fondées sur des enquêtes auprès des ménages existantes et des matériaux qualitatifs originaux, qui vise à : (1) identifier la classe moyenne argentine et sa structure, ainsi que de décrire sa dynamique ; (2) examiner le comportement et les perceptions subjectives du groupe, ainsi que ses attentes en termes de politiques publiques ; et (3) évaluer dans quelle mesure la conception des politiques publiques et des stratégies du marché privé est influencée par la composition et la dynamique de la classe moyenne argentine. Premièrement, notre analyse montre que la tendance à la mobilité ascendante qui a été dominante jusqu'en 2007 et a conduit à l'expansion d'une nouvelle classe moyenne (inférieure) argentine s'est progressivement ralentie et même inversée après 2014. Deuxièmement, la mise en oeuvre d'une analyse en cluster nous a conduit à identifier cinq groupes distincts au sein de la classe moyenne argentine, confirmant ainsi son hétérogénéité. Troisièmement, l'enquête qualitative menée auprès de 40 individus issus de ménages de la classe moyenne à Buenos Aires et Tucuman fournit des comptes rendus détaillés des perceptions et attentes subjectives des différents segments de la classe moyenne argentine. Quatrièmement, notre analyse confirme que la classe moyenne argentine est hétérogène en termes d'orientations politiques. Enfin, une enquête institutionnelle qualitative menée auprès de 12 représentants d'institutions publiques et privées met en évidence la mise en oeuvre récente de programmes publics ou privés spécifiquement dédiés aux ménages de la classe moyenne

Transcriptional markers enable identification of rye-grass (Lolium sp.) plants with non-target -site-based resistance to herbicides inhibiting acetolactate-synthase

Molecular detection of herbicide non-target-site-based resistance (NTSR) classically requires extensively validated NTSR genes. We assessed the feasibility of predicting NTSR phenotypes using expression data of NTSR transcriptional markers, i.e., transcripts which expression levels are statistically correlated to NTSR. Markers were sought by comparative RNA-Seq analysis of untreated NTSR or sensitive plants from four rye-grass populations followed by expression quantification in 299 individual plants with characterised sensitivity to two acetolactate-synthase-inhibiting herbicides. Multivariate analyses were implemented to predict NTSR using combined marker expression data. Nineteen markers (four cytochromes P450, four glutathione-S-transferases, three glycosyltransferases, two ABC transporters, two hydrolases, one aldolase, one peptidase, one transferase and one esterase) expressed significantly higher in NTSR plants were identified. Expression was highest in the most resistant plants. Some markers appeared co-regulated. Combined marker expression data enabled prediction of NTSR phenotypes in individual plants or of resistant plant frequencies in populations. Thus, NTSR detection based on transcriptional markers proved feasible. Accuracy can be improved by identifying additional markers, especially markers associated to NTSR regulation. Additionally, our data suggest that NTSR mechanisms emerged in different populations via redundant evolution, and that NTSR can evolve by selection for higher constitutive expression of whole herbicide-response pathways

Identification de gènes liés à la résistance aux herbicides non liée à la cible chez les Ivraies : vers des tests « moléculaires » de diagnostic

SPEGESTADCT1Identification of genes linked to non-target-site resistance to herbicides in ryegrass : towards "molecular" diagnosis assays. Setting up molecular diagnosis tools would greatly foster preventing and managing non-target-sitebased resistance to herbicides (NTSR). This is currently hampered by the complexity of NTSR genetic determinism, which is largely based upon differences in the expression of an unknown number of genes between resistant and sensitive plants. Identifying NTSR genes is thus a challenging task. Herein, we report the identification of 19 genes which expression patterns are correlated to NTSR to ALS-inhibiting herbicides in rye-grasses (Lolium sp.). We demonstrate the potential of using combined expression data from several of these genes to predict NTSRLe développement de tests moléculaires de détection serait un grand pas en avant dans la prévention et la gestion de la résistance non liée à la cible (RNLC). Les déterminismes génétiques de la RNLC sont cependant complexes, et font largement appel à des différences d’expression d’un nombre inconnu de gènes entre plantes résistantes et plantes sensibles. Leur identification est donc ardue. Dans ce travail, nous décrivons l’identification de 19 gènes dont les profils d’expression sont corrélés à la RNLC à des herbicides inhibiteurs de l’ALS chez les Ivraies (Lolium sp.), et nous montrons le potentiel de l’utilisation des données d’expression combinées de plusieurs de ces gènes pour la prédiction de la RNLC

Transcriptome screening-based identification of candidate genes endowing non-target-site-based resistance to herbicides inhibiting ALS in Lolium sp

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RNA-Seq analysis of rye-grass transcriptomic response to an herbicide inhibiting acetolactate-synthase identifies transcripts linked to non-target-site-based resistance

International audienceNon-target-site resistance (NTSR) to herbicides that disrupts agricultural weed control is a worldwide concern for food security. NTSR is considered a polygenic adaptive trait driven by differential gene regulation in resistant plants. Little is known about its genetic determinism, which precludes NTSR diagnosis and evolutionary studies. We used Illumina RNA-sequencing to investigate transcriptomic differences between plants from the global major weed rye-grass sensitive or resistant to the acetolactate-synthase (ALS) inhibiting herbicide pyroxsulam. Plants were collected before and along a time-course after herbicide application. De novo transcriptome assembly yielded a resource (LOLbase) including 92,381 contigs representing potentially active transcripts that were assigned putative annotations. Early effects of ALS inhibition consistent with the literature were observed in resistant and sensitive plants, proving LOLbase data were relevant to study herbicide response. Comparison of resistant and sensitive plants identified 30 candidate NTSR contigs. Further validation using 212 plants resistant or sensitive to pyroxsulam and/or to the ALS inhibitors iodosulfuron + mesosulfuron confirmed four contigs (two cytochromes P450, one glycosyl-transferase and one glutathione-S-transferase) were NTSR markers which combined expression levels could reliably identify resistant plants. This work confirmed that NTSR is driven by differential gene expression and involves different mechanisms. It provided tools and foundation for subsequent NTSR investigations

Characterisation of rye-grass (<em>Lolium</em> sp.) transcriptome-wide response to ALS-inhibiting herbicides

International audienceNon-target-site-resistance (NTSR) to herbicides is a major cause for failure in the chemical control of a number of weeds, and is especially widespread and important in grass weeds. Although several gene families have been shown to be involved in NTSR (cytochromes p450, glutathione-S-transferases, glycosyl-transferases, ABC transporters, esterases…), the genetic determinants of NTSR are still poorly known to date. NTSR is part of the response of weeds to herbicides. To unravel NTSR, it is thus of interest to firstly characterise the processes involved in herbicide stress response in grasses. For this purpose, we implemented a comparative whole-transcriptome sequencing (RNA-seq) of resistant and sensitive plants of Lolium sp. before and after the application of an herbicide inhibiting ALS. The expression of transcripts encoding a total of 81,663 potential peptides was monitored over a time-course experiment ranging from before herbicide application to 48 hours after herbicide application. Comparison among experimental modalities allowed to identify Gene Ontology biological processes and molecular functions with a potential role in herbicide response and in NTSR. The role of the main gene families known to be involved in herbicide detoxification was confirmed in this study. We identified additional processes regulated by the herbicide application (e.g., transcripts involved in plant defence, in drug response, in the regulation of gene expression, in the branched amino-acid biosynthesis pathway, in photosynthesis or in excretion transport). Several transcripts with an expression pattern differentiating herbicide-resistant and herbicide-sensitive plants were also identified that are candidates of interest for NTSR diagnosis purposes

ALOMYbase, a resource to investigate non-target-site-based resistance to herbicides inhibiting acetolactate-synthase (ALS) in the major grass weed <em>Alopecurus myosuroides</em> (black-grass)

International audienceBackground: Herbicide resistance in agrestal weeds is a global problem threatening food security. Non-target-site resistance (NTSR) endowed by mechanisms neutralising the herbicide or compensating for its action is considered the most agronomically noxious type of resistance. Contrary to target-site resistance, NTSR mechanisms are far from being fully elucidated. A part of weed response to herbicide stress, NTSR is considered to be largely driven by gene regulation. Our purpose was to establish a transcriptome resource allowing investigation of the transcriptomic bases of NTSR in the major grass weed Alopecurus myosuroides L. (Poaceae) for which almost no genomic or transcriptomic data was available. Results: RNA-Seq was performed from plants in one F2 population that were sensitive or expressing NTSR to herbicides inhibiting acetolactate-synthase. Cloned plants were sampled over seven time-points ranging from before until 73 h after herbicide application. Assembly of over 159M high-quality Illumina reads generated a transcriptomic resource (ALOMYbase) containing 65,558 potentially active contigs (N50 = 1240 nucleotides) predicted to encode 32,138 peptides with 74 % GO annotation, of which 2017 were assigned to protein families presumably involved in NTSR. Comparison with the fully sequenced grass genomes indicated good coverage and correct representation of A. myosuroides transcriptome in ALOMYbase. The part of the herbicide transcriptomic response common to the resistant and the sensitive plants was consistent with the expected effects of acetolactate-synthase inhibition, with striking similarities observed with published Arabidopsis thaliana data. A. myosuroides plants with NTSR were first affected by herbicide action like sensitive plants, but ultimately overcame it. Analysis of differences in transcriptomic herbicide response between resistant and sensitive plants did not allow identification of processes directly explaining NTSR. Five contigs associated to NTSR in the F2 population studied were tentatively identified. They were predicted to encode three cytochromes P450 (CYP71A, CYP71B and CYP81D), one peroxidase and one disease resistance protein. Conclusions: Our data confirmed that gene regulation is at the root of herbicide response and of NTSR. ALOMYbase proved to be a relevant resource to support NTSR transcriptomic studies, and constitutes a valuable tool for future research aiming at elucidating gene regulations involved in NTSR in A. myosuroides

Alopecurus myosuroides transcriptome database (ALOMYBase): unravelling the genetic bases of non-target-site-based resistance to herbicides

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