Responses to hydric stress in the seed-borne necrotrophic fungus Alternaria brassicicola

Alternaria brassicicola is a necrotrophic fungus causing black spot disease and is an economically important seed-borne pathogen of cultivated brassicas. Seed transmission is a crucial component of its parasitic cycle as it promotes long-term survival and dispersal. Recent studies, conducted with the Arabidopsis thaliana/A. brassicicola pathosystem, showed that the level of susceptibility of the fungus to water stress strongly influenced its seed transmission ability. In this study, we gained further insights into the mechanisms involved in the seed infection process by analyzing the transcriptomic and metabolomic responses of germinated spores of A. brassicicola exposed to water stress. Then, the repertoire of putative hydrophilins, a group of proteins that are assumed to be involved in cellular dehydration tolerance, was established in A. brassicicola based on the expression data and additional structural and biochemical criteria. Phenotyping of single deletion mutants deficient for fungal hydrophilin-like proteins showed that they were affected in their transmission to A. thaliana seeds, although their aggressiveness on host vegetative tissues remained intact

Aides au diagnostic à base d'intelligence artificielle pour l'architecture de surveillance PSAD

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Méthodes d'intelligence artificielle pour le diagnostic

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Water deficit enhances C export to the roots in A. thaliana plants with contribution of sucrose transporters in both shoot and roots

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Attentional bias and response inhibition in severe obesity with food disinhibition: a study of P300 and N200 event-related potential

International audienceBACKGROUND/OBJECTIVE: In obesity there is growing evidence for common mechanism between food intake regulation and substance use disorders, especially more attentional bias and less cognitive control. In the present study we investigated whether severely obese subjects with or without disordered eating exhibit electroencephalographic (EEG) event-related potential (ERP) modifications as observed in substance abusers. SUBJECTS/METHODS: A total of 90 women were included; 30 in the normal-weight (NW) group (18.5 \textless BMI \textless 24.5 kg/m(2); no food disinhibition or restriction on the Three-Factor Eating Questionnaire) and 60 participants with BMI \textgreater/= 35 kg/m(2) were separated into two groups (n = 30): without food disinhibition (disinhibition score \textless/=8; ObFD- group) and with food disinhibition (score \textgreater8; ObFD+). Clinical and metabolic parameters as well as compartmental aspects (Eating Disorders Inventory-2, EDI-2) were assessed. Participants underwent an ERP recording with an auditory oddball paradigm. RESULTS: The mean +/- SD P300 amplitudes in Pz were significantly (p \textless 0.05) lower in ObFD- (12.4 +/- 4.6) and ObFD+ (12.5 +/- 4.4) groups than in the NW group (15.8 +/- 5.9). The mean +/- SD N200 amplitude in Cz was significantly lower in the ObFD- group (-2.0 +/- 5.4) than in the NW group (-5.2 +/- 4.2 vs; p = 0.035). N200 Cz amplitude was correlated with EDI-2 Binge eating risk score (rho = 0.331; p = 0.01), EDI-2 Body Dissatisfaction score (rho = 0.351; p = 0.007), and Drive for Thinness score (rho = 0.26; p = 0.05). CONCLUSIONS: The present study provides evidence for reduction of P300 and N200 amplitude in obese women and that N200 amplitude may be related to more disordered eating and eating disorder risk. This leads to consider attentional bias and response inhibition as core mechanisms in obesity and as possible targets for new therapeutic strategy

Genome‐wide transcriptional responses to water deficit during seed development in Pisum sativum , focusing on sugar transport and metabolism

International audienceAgriculture is particularly impacted by global changes, drought being a main limiting factor of crop production. Here, we focus on pea (Pisum sativum), a model legume cultivated for its seed nutritional value. A water deficit (WD) was applied during its early reproductive phase, harvesting plant organs at two key developmental stages, either at the embryonic or the seed‐filling stages. We combined phenotypic, physiological and transcriptome analyses to better understand the adaptive response to drought. First, we showed that apical growth arrest is a major phenotypic indicator of water stress. Sugar content was also greatly impacted, especially leaf fructose and starch contents. Our RNA‐seq analysis identified 2001 genes regulated by WD in leaf, 3684 genes in root and 2273 genes in embryonic seed, while only 80 genes were regulated during seed‐filling. Hence, a large transcriptional reprogramming occurred in response to WD in seeds during early embryonic stage, but no longer during the later stage of nutritional filling. Biological processes involved in transcriptional regulation, carbon transport and metabolism were greatly regulated by WD in both source and sink organs, as illustrated by the expression of genes encoding transcription factors, sugar transporters and enzymes of the starch synthesis pathway. We then looked at the transcriptomic changes during seed development, highlighting a transition from monosaccharide utilization at the embryonic stage to sucrose transport feeding the starch synthesis pathway at the seed‐filling stage. Altogether, our study presents an integrative picture of sugar transport and metabolism in response to drought and during seed development at a genome‐wide level

Characterization of AgMaT2, a Plasma Membrane Mannitol Transporter from Celery, Expressed in Phloem Cells, Including Phloem Parenchyma Cells[OA]

A second mannitol transporter, AgMaT2, was identified in celery (Apium graveolens L. var. dulce), a species that synthesizes and transports mannitol. This transporter was successfully expressed in two different heterologous expression systems: baker's yeast (Saccharomyces cerevisiae) cells and tobacco (Nicotiana tabacum) plants (a non-mannitol-producing species). Data indicated that AgMaT2 works as an H+/mannitol cotransporter with a weak selectivity toward other polyol molecules. When expressed in tobacco, AgMaT2 decreased the sensitivity to the mannitol-secreting pathogenic fungi Alternaria longipes, suggesting a role for polyol transporters in defense mechanisms. In celery, in situ hybridization showed that AgMaT2 was expressed in the phloem of leaflets, petioles from young and mature leaves, floral stems, and roots. In the phloem of petioles and leaflets, AgMaT2, as localized with specific antibodies, was present in the plasma membrane of three ontologically related cell types: sieve elements, companion cells, and phloem parenchyma cells. These new data are discussed in relation to the physiological role of AgMaT2 in regulating mannitol fluxes in celery petioles

Structural details in Li3PS4: Variety in thiophosphate building blocks and correlation to ion transport

International audienceLi3PS4 is an attractive solid-electrolyte material that possesses high RT ionic conductivity (10(-4) S.cm(-1) ) but the effects of specific synthesis parameters on the material's local structure and transport properties still demand clarifications. Herein, we highlight the substantial effects of cooling breaks in the mechanochemical synthesis procedure on the formation of a variety of PxSya- moieties and on the transport properties of Li3PS4, through Raman and impedance spectroscopy measurements. We show that ball-milled Li3PS4 (with no subsequent annealing), which is often regarded as ``amorphous/glass/glassy Li3PS4 ``, is not fully amorphous using X-ray diffraction and transmission electron microscopy. Upon subsequent annealing for 1 h above 190 degrees C, beta-Li3PS4 is crystallized and our P-31 magic angle spinning nuclear magnetic resonance spectra suggest that 3 distinct PS43- moieties form, which we refer to as amorphous-, beta-and gamma-type units. Herein, we present a hypothesis to explain the correlation between the ionic conductivity and the distinct PS43- units as a function of the annealing temperature. Our results consolidate the recent reports noting that crystallization of beta-Li3PS4 is not necessary to obtain a high conductivity in ball-milled Li3PS4. Finally, we introduce a phase mixture between beta-Li3PS4 and gamma-Li3PS4 synthesized at 200 degrees C, which is the lowest synthesis temperature yet for gamma-Li3PS4

Protein farnesylation is involved in nitrogen starvation adaptation in Arabidopsis

International audienceNitrogen is an important element that controls plant growth and yield. Recently we showed that protein farnesylation is involved in nitrate-driven root architecture organization in Arabidopsis. In this study, we aimed to deeper investigate the role of this post-translational maturation in plant responses to nitrogen, by studying the metabolic and phenotypic adaptations of the era1.8 mutant (enhanced response to abscisic acid 1; i.e. lacking protein farnesylation activity) to various NH4NO3 supplies. WT and era1.8 plants were grown on low-nitrogen substrate supplemented with 0, 2 or 10 mM NH4NO3, and were analyzed for biomass production and carbonand nitrogen-related metabolites. Our results showed that compared to WT, era1.8 developed exacerbated responses to N starvation, i.e. a higher root/shoot ratio, a higher anthocyanins content and a higher carbon/nitrogen ratio. Moreover, transcriptomic analyzes revealed an over-expression of several genes related to nitrogen starvation adaptation in era1.8 and pointed out two genes encoding uncharacterized farnesylated proteins. At 2 and 10 mM NH4NO3, although the era1.8 mutant displayed a higher biomass, its metabolism and gene expression are comparable to that of WT. Overall, our results show that era1.8 develops exacerbated responses to nitrogen starvation with specific metabolic balances, highlighting that protein farnesylation participates to plant adaptation to nitrogen nutritional stress

Disruption of the Sugar Transporters AtSWEET11 and AtSWEET12 Affects Vascular Development and Freezing Tolerance in Arabidopsis

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