GIGANTEA adjusts the response to shade at dusk by directly impinging on PHYTOCHROME INTERACTING FACTOR 7 function.

For plants adapted to bright light, a decrease in the amount of light received can be detrimental to their growth and survival. Consequently, in response to shade from surrounding vegetation, they initiate a suite of molecular and morphological changes known as the shade avoidance response through which stems and petioles elongate in search for light. Under sunlight-night cycles, the plant's responsiveness to shade varies across the day, being maximal at dusk time. While a role for the circadian clock in this regulation has long been proposed, mechanistic understanding of how it is achieved is incomplete. Here, we show that the clock component GIGANTEA (GI) directly interacts with the transcriptional regulator PHYTOCHROME INTERACTING FACTOR 7 (PIF7), a key player in the response to shade. GI represses PIF7 transcriptional activity and the expression of its target genes in response to shade, thereby fine-tuning the magnitude of the response to limiting light conditions. We find that under light/dark cycles, this function of GI is required to adequately modulate the gating of the response to shade at dusk. Importantly, we also show that this circuit primarily operates in epidermal cells, highlighting the relevance of tissue-specific clock-output connections for the regulation of plant development in resonance with the environment.

Genetic and Phenotypic Analyses of Carpel Development in Arabidopsis.

Carpels are the female reproductive organs of the flower, organized in a gynoecium, which is likely the most complex organ of the plant. The gynoecium provides protection for the ovules, helps to discriminate between male gametophytes, and facilitates successful pollination. After fertilization, it develops into a fruit, a specialized organ for seed protection and dispersal. To carry out all these functions, coordinated patterning and tissue specification within the developing gynoecium has to be achieved. In this chapter, we provide different methods to characterize defects in carpel morphogenesis and patterning associated with developmental mutations, as well as a list of reporter lines that can be used to facilitate genetic analyses.

Consenso venezolano para el uso de la resonancia magnética en el diagnóstico y seguimiento de pacientes con esclerosis múltiple / Venezuelan consensus guidelines on the use of magnetic resonance in diagnosis and follow up of patients with multiple sclerosis

Introducción. El uso de la resonancia magnética (RM) en el diagnóstico y seguimiento de pacientes con esclerosis múltiple (EM) se ha incrementado considerablemente durante los últimos años. Diversos grupos de trabajo internacionales han intentado clarificar y normativizar el uso de la RM tanto en el momento del diagnóstico como durante el seguimiento de los pacientes. Sin embargo, en muchas ocasiones se extrapolan datos de otras regiones que no contemplan la realidad de cada lugar o son difíciles de implementar. Objetivo. Elaborar un consenso venezolano para el uso de la RM en el diagnóstico y seguimiento de pacientes con EM. Desarrollo. Un grupo de expertos de Venezuela, conformado por neurólogos y radiólogos, mediante metodología de ronda de encuestas a distancia y reuniones presenciales, llevó adelante la elaboración del consenso pretendido para el uso de la RM en el diagnóstico y seguimiento de pacientes con EM en Venezuela. Se establecieron 17 recomendaciones basadas en la evidencia publicada y en el criterio de los expertos que participaron. Las recomendaciones se enfocaron en el papel de las técnicas convencionales de RM, así como en el de la medición de la atrofia cerebral en pacientes con EM, tanto en el momento del diagnóstico como durante el seguimiento. Conclusión. Las recomendaciones establecidas en el presente consenso permitirán optimizar el cuidado y el seguimiento de los pacientes con EM en Venezuela (AU)

Introduction. The clinical use of magnetic resonance (MR) in patients with multiple sclerosis (MS) has advanced markedly over the past few years. Several groups around the world have developed consensus guidelines about the role of MR in MS at diagnosis and during follow up. However, in some regions is difficult to extrapolate the recommendations. Aim. To provide recommendations for the implementation of MR in MS patients at diagnosis and follow up in Venezuela. Development. A group of experts from Venezuela that included neurologists and radiologists, by using the online surveys methodology as well as face to face meetings developed the intended consensus for the use of MR during the diagnosis and follow up of MS patients in Venezuela. Seventeen recommendations were established based on published evidence and the expert opinion. Recommendations focused on the role of conventional MR techniques and brain atrophy measurement in MS patients both at diagnosis and during follow-up. Conclusions. The recommendations of this consensus guidelines attempts to optimize the health care and management of patients with MS in Venezuela (AU)