Impact of high atmospheric carbon dioxide on the biotic stress response of the model cereal species Brachypodium distachyon

Losses due to disease and climate change are among the most important issues currently facing crop production. It is therefore important to establish the impact of climate change, and particularly of high carbon dioxide (hCO2), on plant immunity in cereals, which provide 60% of human calories. The aim of this study was to determine if hCO2 impacts Brachypodium distachyon immunity, a model plant for temperate cereals. Plants were grown in air (430 ppm CO2) and at two high CO2 conditions, one that is relevant to projections within the coming century (1000 ppm) and a concentration sufficient to saturate photosynthesis (3000 ppm). The following measurements were performed: phenotyping and growth, salicylic acid contents, pathogen resistance tests, and RNAseq analysis of the transcriptome. Improved shoot development was observed at both 1000 and 3000 ppm. A transcriptomic analysis pointed to an increase in primary metabolism capacity under hCO2. Alongside this effect, up-regulation of genes associated with secondary metabolism was also observed. This effect was especially evident for the terpenoid and phenylpropanoid pathways, and was accompanied by enhanced expression of immunity-related genes and accumulation of salicylic acid. Pathogen tests using the fungus Magnaporthe oryzae revealed that hCO2 had a complex effect, with enhanced susceptibility to infection but no increase in fungal development. The study reveals that immunity in B. distachyon is modulated by growth at hCO2 and allows identification of pathways that might play a role in this effect

Problèmes méthodologiques liés à la comparaison internationale des niveaux de vie dans une perspective historique : application à l'Europe de 1820

The objective of this thesis is to indentify the methodological problems in international comparisons of life levels in historical perspective and particularly in Europe in 1820. European societies have undergonedeep changes at the beginning of the XIX's implying various consequences on life levels. This thesis is organized in two parts. The first part compares methodologies of specialists like P. Bairoch and A . Maddison. The second part presents and studies P. Bairoch's physical indicators methodology applied in the Europe at the beginning of the XIX's. Two types of result come out of the first part. Fisrt, we show the importance of the aggregation of the output sets on the basis of Purchasing Power Parities (PPA) to convert the sectoral output value to a common currency. Second, new personal methodologies are satisfactory. Moreover, L. Prado's methodology is particularly effective. The second part emphasises physical indicators like efficient in the determination of life level in 1820. We use wheat , agricultural productivity, consumption of coal, iron and cotton, per capita and a set of demographic data. This macroeconomic is completed by a microeconomic study using prices, nominal and real wages. Finaly, the Huma Development Index (version III) shows that United Kingdom's life level was superior of 30% on the French in 1820.L'objectif de cette thèse consiste à identifier les problèmes méthodologiques liés à la comparaison internationale des niveaux de vie dans une perspective historique et ce, dans le cadre de l'Europe de 1820. La thèse est organisée en deux parties - la première partie met en perspective les méthodologies adoptées par les spécialistes de série longues tels P. Bairoch et A. Maddison. La seconde s'intéresse à approfondir la réflexion de P. Bairoch par la recherche d'indicateurs physiques de niveau de vie et d'écarts relatifs dans le cadre de l'Europe de 1820. La première partie permet de mettre en évidence deux types de résultat. Le premier montre l'importance du mode d'agrégation des données par les parités de pouvoir d'achat. La seconde démontre la cohérence des nouvelles méthodologies d'estimation de niveau de vie telles que celles élaborées personnellement et la méthode par itération de L. Prados de la Escosura. La seconde partie met en évidence l'existence d'indicateurs indirects de nature physique, complémentaire des agrégats " classiques " de compatibilité nationale, tels que le rendement de blé, la productivité du travail agricole, la consommation de fer par habitant ainsi qu'un ensemble de variables démographiques. Cette analyse macroéconomique se complète alors par une réflexion fondée sur les inégalités de revenus puis sur les pouvoirs d'achat de grand intérêt. En appliquant l'indicateur de développement humain (version III), nous avons finalement établi que la Grande-Bretagne avait en 1820 un niveau de vie supérieur de 30 % environ à celui de la France

A single mutation in the 15S rRNA gene confers nonsense suppressor activity and interacts with mRF1 the release factor in yeast mitochondria

We have determined the nucleotide sequence of the mim3-1 mitochondrial ribosomal suppressor, acting on ochre mitochondrial mutations and one frameshift mutation in Saccharomyces cerevisiae. The 15s rRNA suppressor gene contains a G633 to C transversion. Yeast mitochondrial G633 corresponds to G517 of the E.coli 15S rRNA, which is occupied by an invariant G in all known small rRNA sequences. Interestingly, this mutation has occurred at the same position as the known MSU1 mitochondrial suppressor which changes G633 to A. The suppressor mutation lies in a highly conserved region of the rRNA, known in E.coli as the 530-loop, interacting with the S4, S5 and S12 ribosomal proteins. We also show an interesting interaction between the mitochondrial mim3-1 and the nuclear nam3-1 suppressors, both of which have the same action spectrum on mitochondrial mutations: nam3-1 abolishes the suppressor effect when present with mim3-1 in the same haploid cell. We discuss these results in the light of the nature of Nam3, identified by [1] as the yeast mitochondrial translation release factor. A hypothetical mechanism of suppression by "ribosome shifting" is also discussed in view of the nature of mutations suppressed and not suppressed

Overexpression of a Cytochrome P450 Monooxygenase Involved in Orobanchol Biosynthesis Increases Susceptibility to Fusarium Head Blight

International audienceFusarium Head Blight (FHB) is a cereal disease caused primarily by the ascomycete fungus Fusarium graminearum with public health issues due to the production of mycotoxins including deoxynivalenol (DON). Genetic resistance is an efficient protection means and numerous quantitative trait loci have been identified, some of them related to the production of resistance metabolites. In this study, we have functionally characterized the Brachypodium distachyon BdCYP711A29 gene encoding a cytochrome P450 monooxygenase (CYP). We showed that BdCYP711A29 belongs to an oligogenic family of five members. However, following infection by F. graminearum , BdCYP711A29 is the only copy strongly transcriptionally induced in a DON-dependent manner. The BdCYP711A29 protein is homologous to the Arabidopsis thaliana MAX1 and Oryza sativa MAX1-like CYPs representing key components of the strigolactone biosynthesis. We show that BdCYP711A29 is likely involved in orobanchol biosynthesis. Alteration of the BdCYP711A29 sequence or expression alone does not modify plant architecture, most likely because of functional redundancy with the other copies. B. distachyon lines overexpressing BdCYP711A29 exhibit an increased susceptibility to F. graminearum , although no significant changes in defense gene expression were detected. We demonstrate that both orobanchol and exudates of Bd711A29 overexpressing lines stimulate the germination of F. graminearum macroconidia. We therefore hypothesize that orobanchol is a susceptibility factor to FHB

Impact of high atmospheric carbon dioxide on the biotic stress response of the model cereal species Brachypodium distachyon

International audienceLosses due to disease and climate change are among the most important issues currently facing crop production. It is therefore important to establish the impact of climate change, and particularly of high carbon dioxide (hCO 2 ), on plant immunity in cereals, which provide 60% of human calories. The aim of this study was to determine if hCO 2 impacts Brachypodium distachyon immunity, a model plant for temperate cereals. Plants were grown in air (430 ppm CO 2 ) and at two high CO 2 conditions, one that is relevant to projections within the coming century (1000 ppm) and a concentration sufficient to saturate photosynthesis (3000 ppm). The following measurements were performed: phenotyping and growth, salicylic acid contents, pathogen resistance tests, and RNAseq analysis of the transcriptome. Improved shoot development was observed at both 1000 and 3000 ppm. A transcriptomic analysis pointed to an increase in primary metabolism capacity under hCO 2 . Alongside this effect, up-regulation of genes associated with secondary metabolism was also observed. This effect was especially evident for the terpenoid and phenylpropanoid pathways, and was accompanied by enhanced expression of immunity-related genes and accumulation of salicylic acid. Pathogen tests using the fungus Magnaporthe oryzae revealed that hCO 2 had a complex effect, with enhanced susceptibility to infection but no increase in fungal development. The study reveals that immunity in B. distachyon is modulated by growth at hCO 2 and allows identification of pathways that might play a role in this effect

A <em>Brachypodium</em> UDP-glycosyltransferase confers root tolerance to deoxynivalenol and resistance to <em>Fusarium</em> infection

International audienceFusarium head blight (FHB) is a cereal disease caused by Fusarium graminearum, a fungus able to produce type B trichothecenes on cereals, including deoxynivalenol (DON), which is harmful for humans and animals. Resistance to FHB is quantitative, and the mechanisms underlying resistance are poorly understood. Resistance has been related to the ability to conjugate DON into a glucosylated form, deoxynivalenol-3-O-glucose (D3G), by secondary metabolism UDP-glucosyltransferases (UGTs). However, functional analyses have never been performed within a single host species. Here, using the model cereal species Brachypodium distachyon, we show that the Bradi5g03300 UGT converts DON into D3G in planta. We present evidence that a mutation in Bradi5g03300 increases root sensitivity to DON and the susceptibility of spikes to F. graminearum, while overexpression confers increased root tolerance to the mycotoxin and spike resistance to the fungus. The dynamics of expression and conjugation suggest that the speed of DON conjugation rather than the increase of D3G per se is a critical factor explaining the higher resistance of the overexpressing lines. A detached glumes assay showed that overexpression but not mutation of the Bradi5g03300 gene alters primary infection by F. graminearum, highlighting the involvement of DON in early steps of infection. Together, these results indicate that early and efficient UGT-mediated conjugation of DON is necessary and sufficient to establish resistance to primary infection by F. graminearum and highlight a novel strategy to promote FHB resistance in cereals

DataSheet_1_Identification of beneficial Lebanese Trichoderma spp. wheat endophytes.pdf

Wheat is one of the most important crops in the world. Its production can be influenced by a diversity of beneficial and pathogenic rhizospheric microbes, including fungi. Amongst them, beneficial Trichoderma spp. can be used as alternatives to chemical fertilizers, as they are cheap and harmless to the environment. Our study aimed to isolate, identify, and characterize Trichoderma spp. from Lebanon associated with wheat. Two Trichoderma strains belonging to T. afroharzianum, and T. guizhouense species, were isolated and found to be endophytes, enhancing root growth and producing Indole-3-acetic acid. Inoculation also improved seedling development, and increased plant growth and yield. Furthermore, the two strains inhibit Fusarium growth in vitro. These Trichoderma spp. have thus the capacity to be used as organic fertilizers for wheat.</p

Convergence of patient- and physician-reported outcomes in the French National Registry of Facioscapulohumeral Dystrophy

International audienceFacioscapulohumeral muscular dystrophy (FSHD) is among the most prevalent muscular dystrophies and currently has no treatment. Clinical and genetic heterogeneity are the main challenges to a full comprehension of the physiopathological mechanism. Improving our knowledge of FSHD is crucial to the development of future therapeutic trials and standards of care. National FSHD registries have been set up to this end. The French National Registry of FSHD combines a clinical evaluation form (CEF) and a self-report questionnaire (SRQ), filled out by a physician with expertise in neuromuscular dystrophies and by the patient, respectively. Aside from favoring recruitment, our strategy was devised to improve data quality. Indeed, the pairwise comparison of data from 281 patients for 39 items allowed for evaluating data accuracy. Kappa or intra-class coefficient (ICC) values were calculated to determine the correlation between answers provided in both the CEF and SRQ. Results Patients and physicians agreed on a majority of questions common to the SRQ and CEF (24 out of 39). Demographic, diagnosis- and care-related questions were generally answered consistently by the patient and the medical practitioner (kappa or ICC values of most items in these groups were greater than 0.8). Muscle function-related items, i.e. FSHD-specific signs, showed an overall medium to poor correlation between data provided in the two forms; the distribution of agreements in this section was markedly spread out and ranged from poor to good. In particular, there was very little agreement regarding the assessment of facial motricity and the presence of a winged scapula. However, patients and physicians agreed very well on the Vignos and Brooke scores. The report of symptoms not specific to FSHD showed general poor consistency. Conclusions Patient and physician answers are largely concordant when addressing quantitative and objective items. Consequently, we updated collection forms by relying more on patient-reported data where appropriate. We hope the revised forms will reduce data collection time while ensuring the same quality standard. With the advent of artificial intelligence and automated decision-making, high-quality and reliable data are critical to develop top-performing algorithms to improve diagnosis, care, and evaluate the efficiency of upcoming treatments