Touch induces ATP release in Arabidopsis roots that is modulated by the heterotrimeric G-protein complex

Amongst the many stimuli orienting the growth of plant roots, of critical importance are the touch signals generated as roots explore the mechanically complex soil environment. However, the molecular mechanisms behind these sensory events remain poorly defined. We report an impaired obstacle-avoiding response of roots in Arabidopsis lacking a heterotrimeric G protein. Obstacle avoidance may utilize a touch-induced release of ATP to the extracellular space. While sequential touch stimulation revealed a strong refractory period for ATP release in response to mechanostimulation in wild-type plants, the refractory period in mutants was attenuated, resulting in extracellular ATP accumulation. We propose that ATP acts as an extracellular signal released by mechanostimulation and that the G-protein complex is needed for fine-tuning this response

Involvement of auxin pathways in modulating root architecture during beneficial plantmicroorganism interactions

A wide variety of microorganisms known to produce auxin and auxin precursors form beneficial relationships with plants and alter host root development. Moreover, other signals produced by microorganisms affect auxin pathways in host plants. However, the precise role of auxin and auxin-signalling pathways in modulating plantmicrobe interactions is unknown. Dissecting out the auxin synthesis, transport and signalling pathways resulting in the characteristic molecular, physiological and developmental response in plants will further illuminate upon how these intriguing inter-species interactions of environmental, ecological and economic significance occur. The present review seeks to survey and summarize the scattered evidence in support of known host root modifications brought about by beneficial microorganisms and implicate the role of auxin synthesis, transport and signal transduction in modulating beneficial effects in plants. Finally, through a synthesis of the current body of work, we present outstanding challenges and potential future research directions on studies related to auxin signalling in plantmicrobe interactions

Guide pratique de suivi du transplanté hépatique

International audienceSi l’amélioration des techniques chirurgicales et l’immunosuppresison ont permis le développement avec succès de la transplantation d’organe solide, les complications médicales au long cours persistent et sont responsables d’un déclin de la survie dès la première année après la greffe. Les complications liées au greffon (rejet, récidive de la maladie initiale, thrombose vasculaire), tumorales (cancer de novo ou récidive), cardiovasculaires, infectieuses et rénales sont les principales causes de décès après transplantation hépatique. La prévention, le diagnostic et le management de ces complications restent un véritable défi pour tout praticien prenant en charge ces patients. Une meilleure gestion des facteurs tels que le diabète, la dyslipidémie, l’hypertension artérielle et l’insuffisance rénale, peut avoir une incidence sur la mortalité à long terme. Un suivi standardisé associé à un dépistage organisé des complications médicales et chirurgicales sont donc indispensables afin d’adapter précocement la prise en charge et ainsi améliorer la survie après la greffe