Distinct Effects of p19 RNA Silencing Suppressor on Small RNA Mediated Pathways in Plants

RNA silencing is one of the main defense mechanisms employed by plants to fight viruses. In change, viruses have evolved silencing suppressor proteins to neutralize antiviral silencing. Since the endogenous and antiviral functions of RNA silencing pathway rely on common components, it was suggested that viral suppressors interfere with endogenous silencing pathway contributing to viral symptom development. In this work, we aimed to understand the effects of the tombusviral p19 suppressor on endogenous and antiviral silencing during genuine virus infection. We showed that ectopically expressed p19 sequesters endogenous small RNAs (sRNAs) in the absence, but not in the presence of virus infection. Our presented data question the generalized model in which the sequestration of endogenous sRNAs by the viral suppressor contributes to the viral symptom development. We further showed that p19 preferentially binds the perfectly paired ds-viral small interfering RNAs (vsiRNAs) but does not select based on their sequence or the type of the 5’ nucleotide. Finally, co-immunoprecipitation of sRNAs with AGO1 or AGO2 from virus-infected plants revealed that p19 specifically impairs vsiRNA loading into AGO1 but not AGO2. Our findings, coupled with the fact that p19-expressing wild type Cymbidium ringspot virus (CymRSV) overcomes the Nicotiana benthamiana silencing based defense killing the host, suggest that AGO1 is the main effector of antiviral silencing in this host-virus combination

An Evaluation-driven design approach to develop learning environments based on full-body interaction

The development of learning environments based on full-body interaction has become an increasingly important field of research in recent years. However, the design and evaluation strategies currently used present some significant limitations. Two major shortcomings are: the inadequate involvement of children in the design process and a lack of research into what meanings children construct within these learning environments. To tackle these shortcomings we present an evaluation-driven design approach, which aims at analyzing situated interpretations made by children. These interpretations are then used to guide and optimize design in an iterative process of design and assessment. This evaluation-driven design method was applied in the development of the EcoSystem Project, a full-body interaction learning environment for children aimed at supporting learning about environmental relationships. The application of this iterative approach proved to be highly effective both in facilitating continuous improvements in the proposed design and in reducing misconceptions by children using the environment. Moreover, experimental evaluation reported significant learning gains in children. This suggests both the potential of using full-body interaction to support learning and the effectiveness of our evaluation-driven approach in optimizing design solutions through the analysis of children’s interpretations.We thank the Spanish Ministry of Economy and Competitiveness (Grant TIN2014-60599-P) to support the project. We also thank all the participants from local schools for their time and motivation during the participatory design workshop. We are also very grateful for the valuable information and materials on environmental education provided by experts from Fàbrica del Sol, Ecoserveis, Aula Ambiental de la Sagrada Família, Societat Catalana d‘Educació Ambiental (SCED) and Centre de Suport a la Innovació i la Recerca Educativa (CESIRE)