Characterisation of the Fusarium graminearum-Wheat Floral Interaction

Fusarium Ear Blight is a destructive fungal disease of cereals including wheat and can contaminate the crop with various trichothecene mycotoxins. This investigation has produced a new β-glucuronidase (GUS) reporter strain that facilitates the quick and easy assessment of plant infection. The constitutively expressed gpdA:GUS strain of Fusarium graminearum was used to quantify the overall colonisation pattern. Histochemical and biochemical approaches confirmed, in susceptible wheat ear infections, the presence of a substantial phase of symptomless fungal growth. Separate analyses demonstrated that there was a reduction in the quantity of physiologically active hyphae as the wheat ear infection proceeded. A simplified linear system of rachis infection was then utilised to evaluate the expression of several TRI genes by RT-qPCR. Fungal gene expression at the advancing front of symptomless infection was compared with the origin of infection in the rachis. This revealed that TRI gene expression was maximal at the advancing front and supports the hypothesis that the mycotoxin deoxynivalenol plays a role in inhibiting plant defences in advance of the invading intercellular hyphae. This study has also demonstrated that there are transcriptional differences between the various phases of fungal infection and that these differences are maintained as the infection proceeds

Heritability and Artificial Selection on Ambulatory Dispersal Distance in Tetranychus urticae: Effects of Density and Maternal Effects

Dispersal distance is understudied although the evolution of dispersal distance affects the distribution of genetic diversity through space. Using the two-spotted spider mite, Tetranychus urticae, we tested the conditions under which dispersal distance could evolve. To this aim, we performed artificial selection based on dispersal distance by choosing 40 individuals (out of 150) that settled furthest from the home patch (high dispersal, HDIS) and 40 individuals that remained close to the home patch (low dispersal, LDIS) with three replicates per treatment. We did not observe a response to selection nor a difference between treatments in life-history traits (fecundity, survival, longevity, and sex-ratio) after ten generations of selection. However, we show that heritability for dispersal distance depends on density. Heritability for dispersal distance was low and non-significant when using the same density as the artificial selection experiments while heritability becomes significant at a lower density. Furthermore, we show that maternal effects may have influenced the dispersal behaviour of the mites. Our results suggest primarily that selection did not work because high density and maternal effects induced phenotypic plasticity for dispersal distance. Density and maternal effects may affect the evolution of dispersal distance and should be incorporated into future theoretical and empirical studies

Agir

Ce numéro se tourne vers l’action et l’amélioration des situations de travail, des thèmes chers à la revue PISTES. Il est question de différents types d’intervention pour agir sur les conditions d’exercice du travail, mais aussi pour accompagner le développement des personnes

Financiarisation et travail

Le “Corpus” de ce numéro de La Nouvelle Revue du Travail est consacré aux interdépendances entre la financiarisation de l’économie et les transformations contemporaines du travail. L’entrée privilégiée ici est la gestion, ses acteurs et ses dispositifs, instances intermédiaires grâce auxquelles le macro-économique conforme le microsocial, à travers les métamorphoses imprimées au travail. C’est en particulier autour de l’étude critique des actes désormais omniprésents de mesures physiques et de valorisations comptables des activités de travail conduits par les managers (ou les gestionnaires) que s’est construit ce numéro. Dit autrement, les articles ici rassemblés cherchent à éclairer les différentes manières dont les impératifs de rentabilité financière sont réinterprétés en termes de décisions de rationalisation du travail et marquent les organisations contemporaines – qu’elles soient publiques ou privées – du même réductionnisme calculatoire, sans oublier les réactions ou les résistances des personnels concernés. Procéder à un tel choix, c’est renouer avec une ambition initiale de la sociologie, quand Durkheim et les membres de L’Année sociologique discutaient les impensés anthropologiques de l’économie politique, ou quand Weber, Sombart ou Marx nous invitaient à nous intéresser à la comptabilité pour comprendre comment le capitalisme entraînait le travail dans les voies qui étaient les siennes