The Times They Are A-Changin’: Heterochrony in Plant Development and Evolution

Alterations in the timing of developmental programs during evolution, that lead to changes in the shape, or size of organs, are known as heterochrony. Heterochrony has been widely studied in animals, but has often been neglected in plants. During plant evolution, heterochronic shifts have played a key role in the origin and diversification of leaves, roots, flowers, and fruits. Heterochrony that results in a juvenile or simpler outcome is known as paedomorphosis, while an adult or more complex outcome is called peramorphosis. Mechanisms that alter developmental timing at the cellular level affect cell proliferation or differentiation, while those acting at the tissue or organismal level change endogenous aging pathways, morphogen signaling, and metabolism. We believe that wider consideration of heterochrony in the context of evolution will contribute to a better understanding of plant development

EL TELETRABAJO EN TIEMPOS DE COVID: LOS RIESGOS PSICOSOCIALES

Este documento analiza la modalidad laboral del teletrabajo como fenómeno en auge tras la pandemia de la COVID-19 que tuvo inicio en 2020, así como los riesgos que pueden derivar del mismo para los teletrabajadores. Como marco teórico, se expone su trayectoria histórica y legislativa en España, prestando mayor atención a la legislación más reciente e impulsada por la crisis sanitaria. Posteriormente se analizan los aspectos positivos y negativos que presenta esta modalidad y los riesgos psicosociales que provoca en los trabajadores, así como las diferentes opiniones encontradas en cuanto pros y contras en la salud psicosocial de los teletrabajadores, complementando todo ello con un cuestionario que ayude a entender y poner en contexto los aspectos previamente investigados en el marco teórico.<br /

El teletrabajo en tiempos de covid: los riesgos psicosociales.

Este documento analiza la modalidad laboral del teletrabajo como fenómeno en auge tras la pandemia de la COVID-19 que tuvo inicio en 2020, así como los riesgos que pueden derivar del mismo para los teletrabajadores. Como marco teórico, se expone su trayectoria histórica y legislativa en España, prestando mayor atención a la legislación más reciente e impulsada por la crisis sanitaria. Posteriormente se analizan los aspectos positivos y negativos que presenta esta modalidad y los riesgos psicosociales que provoca en los trabajadores, así como las diferentes opiniones encontradas en cuanto pros y contras en la salud psicosocial de los teletrabajadores, complementando todo ello con un cuestionario que ayude a entender y poner en contexto los aspectos previamente investigados en el marco teórico.<br /

El Teletrabajo en tiempos de Covid: los riesgos psicosociales

Este documento analiza la modalidad laboral del teletrabajo como fenómeno en auge tras la pandemia de la COVID-19 que tuvo inicio en 2020, así como los riesgos que pueden derivar del mismo para los teletrabajadores. Como marco teórico, se expone su trayectoria histórica y legislativa en España, prestando mayor atención a la legislación más reciente e impulsada por la crisis sanitaria. Posteriormente se analizan los aspectos positivos y negativos que presenta esta modalidad y los riesgos psicosociales que provoca en los trabajadores, así como las diferentes opiniones encontradas en cuanto pros y contras en la salud psicosocial de losteletrabajadores, complementando todo ello con un cuestionario que ayude a entender y poner en contexto los aspectos previamente investigados en el marco teórico.<br /

Developmental role of the tomato Mediator complex subunit MED18 in pollen ontogeny

[EN] Pollen development is a crucial step in higher plants, which not only makes possible plant fertilization and seed formation, but also determines fruit quality and yield in crop species. Here, we reported a tomato T-DNA mutant, pollen deficient1 (pod1), characterized by an abnormal anther development and the lack of viable pollen formation, which led to the production of parthenocarpic fruits. Genomic analyses and the characterization of silencing lines proved that pod1 mutant phenotype relies on the tomato SlMED18 gene encoding the subunit 18 of Mediator multi-protein complex involved in RNA polymerase II transcription machinery. The loss of SlMED18 function delayed tapetum degeneration, which resulted in deficient microspore development and scarce production of viable pollen. A detailed histological characterization of anther development proved that changes during microgametogenesis and a significant delay in tapetum degeneration are associated with a high proportion of degenerated cells and, hence, should be responsible for the low production of functional pollen grains. Expression of pollen marker genes indicated that SlMED18 is essential for the proper transcription of a subset of genes specifically required to pollen formation and fruit development, revealing a key role of SlMED18 in male gametogenesis of tomato. Additionally, SlMED18 is able to rescue developmental abnormalities of the Arabidopsis med18 mutant, indicating that most biological functions have been conserved in both species. Significance Statement Pollination is a key development process in the life cycle of flowering plants. Genetic and molecular characterization of a tomato mutant have led to the identification of POD1 gene encoding the Mediator complex subunit MED18 whose function is required for tapetum tissue degeneration, a crucial step for pollen development. Furthermore, we show that MED18 fulfils an essential role in tomato, ensuring proper gene regulation during pollen ontogeny.This research was supported by the Spanish Ministry of Economy and Competitiveness (grants AGL2015-64991-C3-1-R, AGL2015-64991-C3-2-R, AGL2015-64991-C3-3-R, BIO2013-43098-R, BFU2016-77243-P and BIO2016-77559-R) and Junta de Andalucia (grant P12-AGR-1482).Pérez Martín, F.; Juan Yuste-Lisbona, F.; Pineda, B.; García Sogo, B.; Del Olmo, I.; Alché, JDD.; Egea, I.... (2018). Developmental role of the tomato Mediator complex subunit MED18 in pollen ontogeny. The Plant Journal. 96(2):300-315. https://doi.org/10.1111/tpj.14031S300315962Allen, B. L., & Taatjes, D. J. (2015). 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