The Wor1-like Protein Fgp1 Regulates Pathogenicity, Toxin Synthesis and Reproduction in the Phytopathogenic Fungus Fusarium graminearum

WOR1 is a gene for a conserved fungal regulatory protein controlling the dimorphic switch and pathogenicity determents in Candida albicans and its ortholog in the plant pathogen Fusarium oxysporum, called SGE1, is required for pathogenicity and expression of key plant effector proteins. F. graminearum, an important pathogen of cereals, is not known to employ switching and no effector proteins from F. graminearum have been found to date that are required for infection. In this study, the potential role of the WOR1-like gene in pathogenesis was tested in this toxigenic fungus. Deletion of the WOR1 ortholog (called FGP1) in F. graminearum results in greatly reduced pathogenicity and loss of trichothecene toxin accumulation in infected wheat plants and in vitro. The loss of toxin accumulation alone may be sufficient to explain the loss of pathogenicity to wheat. Under toxin-inducing conditions, expression of genes for trichothecene biosynthesis and many other genes are not detected or detected at lower levels in Δfgp1 strains. FGP1 is also involved in the developmental processes of conidium formation and sexual reproduction and modulates a morphological change that accompanies mycotoxin production in vitro. The Wor1-like proteins in Fusarium species have highly conserved N-terminal regions and remarkably divergent C-termini. Interchanging the N- and C- terminal portions of proteins from F. oxysporum and F. graminearum resulted in partial to complete loss of function. Wor1-like proteins are conserved but have evolved to regulate pathogenicity in a range of fungi, likely by adaptations to the C-terminal portion of the protein

Species-specific Fungal DNA in Airborne Dust as Surrogate for Occupational Mycotoxin Exposure?

Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small dust masses obtained by personal sampling, which is needed for inhalable exposure measurements. Specific and sensitive PCR detection of fungi with mycotoxin-producing potential seem to be a good surrogate for occupational exposure measurements that include all fungal structures independent of morphology and cultivability. Results should, however, be interpreted with caution due to variable correlations with mycotoxin concentrations

A spatial temporal analysis of the Fusarium graminearum transcriptome during symptomless and symptomatic wheat infection

Fusarium head blight of wheat is one of the most serious and hazardous crop diseases worldwide. Here, a transcriptomic investigation of Fusarium graminearum reveals a new model for symptomless and symptomatic wheat infection. The predicted metabolic state and secretome of F. graminearum were distinct within symptomless and symptomatic wheat tissues. Transcripts for genes involved in the biosynthesis of the mycotoxin, deoxynivalenol, plus other characterized and putative secondary metabolite clusters increased in abundance in symptomless tissue. Transcripts encoding for genes of distinct groups of putative secreted effectors increased within either symptomless or symptomatic tissue. Numerous pathogenicity‐associated gene transcripts and transcripts representing PHI‐base mutations that impacted on virulence increased in symptomless tissue. In contrast, hydrolytic carbohydrate‐active enzyme (CAZyme) and lipase gene transcripts exhibited a different pattern of expression, resulting in elevated transcript abundance during the development of disease symptoms. Genome‐wide comparisons with existing datasets confirmed that, within the wheat floral tissue, at a single time point, different phases of infection co‐exist, which are spatially separated and reminiscent of both early and late infection. This study provides novel insights into the combined spatial temporal coordination of functionally characterized and hypothesized virulence strategies

The Predicted Secretome of the Plant Pathogenic Fungus Fusarium graminearum: A Refined Comparative Analysis

The fungus Fusarium graminearum forms an intimate association with the host species wheat whilst infecting the floral tissues at anthesis. During the prolonged latent period of infection, extracellular communication between live pathogen and host cells must occur, implying a role for secreted fungal proteins. The wheat cells in contact with fungal hyphae subsequently die and intracellular hyphal colonisation results in the development of visible disease symptoms. Since the original genome annotation analysis was done in 2007, which predicted the secretome using TargetP, the F. graminearum gene call has changed considerably through the combined efforts of the BROAD and MIPS institutes. As a result of the modifications to the genome and the recent findings that suggested a role for secreted proteins in virulence, the F. graminearum secretome was revisited. In the current study, a refined F. graminearum secretome was predicted by combining several bioinformatic approaches. This strategy increased the probability of identifying truly secreted proteins. A secretome of 574 proteins was predicted of which 99% was supported by transcriptional evidence. The function of the annotated and unannotated secreted proteins was explored. The potential role(s) of the annotated proteins including, putative enzymes, phytotoxins and antifungals are discussed. Characterisation of the unannotated proteins included the analysis of Pfam domains and features associated with known fungal effectors, for example, small size, cysteine-rich and containing internal amino acid repeats. A comprehensive comparative genomic analysis involving 57 fungal and oomycete genomes revealed that only a small number of the predicted F. graminearum secreted proteins can be considered to be either species or sequenced strain specific

Comparative genomics of a plant-pathogenic fungus, pyrenophora tritici-repentis, reveals transduplication and the impact of repeat elements on pathogenicity and population divergence

Pyrenophora tritici-repentis is a necrotrophic fungus causal to the disease tan spot of wheat, whose contribution to crop loss has increased significantly during the last few decades. Pathogenicity by this fungus is attributed to the production of host-selective toxins (HST), which are recognized by their host in a genotype-specific manner. To better understand the mechanisms that have led to the increase in disease incidence related to this pathogen, we sequenced the genomes of three P. tritici-repentis isolates. A pathogenic isolate that produces two known HSTs was used to assemble a reference nuclear genome of approximately 40 Mb composed of 11 chromosomes that encode 12,141 predicted genes. Comparison of the reference genome with those of a pathogenic isolate that produces a third HST, and a nonpathogenic isolate, showed the nonpathogen genome to be more diverged than those of the two pathogens. Examination of gene-coding regions has provided candidate pathogen-specific proteins and revealed gene families that may play a role in a necrotrophic lifestyle. Analysis of transposable elements suggests that their presence in the genome of pathogenic isolates contributes to the creation of novel genes, effector diversification, possible horizontal gene transfer events, identified copy number variation, and the first example of transduplication by DNA transposable elements in fungi.Overall, comparative analysis of these genomes provides evidence that pathogenicity in this species arose through an influx of transposable elements, which created a genetically flexible landscape that can easily respond to environmental changes

L'AMATEUR D'INDICES OU LA METHODE CLINIQUE DU DETECTIVE DANS LES ROMANS DE CONAN DOYLE, AGATHA CHRISTIE ET GEORGES SIMENON.

LA METHODE DES ENQUETEURS DANS LES ROMANS POLICIERS CLASSIQUES SE FONDE SUR LE MODELE HOLMESIEN LUI-MEME ISSU DE LA FORMATION MEDICALE DE CONAN DOYLE. L'ETUDE DE LA METHODE D'INVESTIGATION DE TROIS ENQUETEURS EMBLEMATIQUES - SHERLOCK HOLMES, HERCULE POIROT ET LE COMMISSAIRE MAIGRET - SE FAIT EN DEUX TEMPS. D'ABORD UN INVENTAIRE DES MODELES DU DETECTIVE - LECTEUR, CHASSEUR, SAVANT, MEDECIN - QUI FAIT DE HOLMES UN MEDECIN SPECIALISTE TENTE PAR LES SCIENCES PSYCHIQUES ET MONTRE L'IMPORTANCE FONCTIONNELLE DU MEDECIN DANS LES RECITS DE DETECTION. PUIS UNE ETUDE SYNTHETIQUE DE LA METHODE A PARTIR DU MODELE D'INVESTIGATION DE LA CLINIQUE HIPPOCRATIQUE : OBSERVATION, RAISONNEMENT, SAVOIR. L'OBSERVATION, FONDEE SUR UNE REPRESENTATION DE L'INDICE EN' LESION, EST PARCOURUE PAR L'IMAGINAIRE DE L'AUTOPSIE ; LE RAISONNEMENT, QUI CONSISTE A ETABLIR DES LIENS, S'APPUIE SUR UN SAVOIR PREETABLI QUI FONCTIONNE COMME UN INTERTEXTE. LE SAVOIR, ENVISAGE DU POINT DE VUE DU COMPAGNON DE L'ENQUETEUR, L'AMI MEDECIN, INSCRIT L'INVESTIGATION DANS LA DYNAMIQUE DE LA RIVALITE FRATERNELLE ET SITUE LES RECITS DE DETECTION DANS LE MYTHE GEMELLAIRE. ON VOIT AINSI QU'A LA SUITE D'UN HOLMES MEDECIN ET SORCIER, SITUEA L'INTERSECTION DE LA DECOUVERTE DES MICRO-ORGANISMES ET DE L'EMERGENCE DES SCIENCES PSYCHIQUES, POIROT PRATIQUE UNE CLINIQUE HOLMESIENNE SYSTEMATIQUEMENT APPLIQUEE, PUIS DEVIEE VERS L'ETUDE DES DISCOURS, TANDIS QUE MAIGRET MET EN OEUVRE UNE CLINIQUE INVERSEE. LA METHODE SCIENTIFIQUE DU DETECTIVE EST EN FAIT UN ART ANCESTRAL, LA CLINIQUE, QUI INFLUE SIGNIFICATIVEMENT SUR LA FORME ET L'ECRITURE DES RECITS DE DETECTION.MULHOUSE-SCD Lettres (682242101) / SudocSudocFranceF

Les poésies érotiques d'Evariste Parny

Ce volume fait partie de la collection «Analyses textuelles» (dirigée par Éric Lysøe et Anna Soncini Fratta) qui tire son origine des «Seminari Pasquali di analisi testuale» fondés en 1984 par Ruggero Campagnoli (Université de Bologne). Ces séminaires réunissent chaque année, durant deux ou trois jours, des chercheurs autour d’une oeuvre représentative de la littérature française du XVIe au XXIe siècle